How To Know When Beer Is Done Fermenting?

Monitoring Fermentation – the Scientific Way – The most accurate way to monitor the fermentation process is to use a brewing hydrometer, Taking specific gravity measurements with a brewing hydrometer not only lets one know when fermentation has finished, it also allows one to determine actual alcohol by volume (ABV) of the fermented product.

These numbers can be used for all sorts of things and we discuss all of this in our article on monitoring fermentation (the scientific way). Remember, it is generally legal to brew beer everywhere in the United States. However distilling high proof alcohol at home for consumption is illegal. Our distillation equipment is designed for legal uses only and the information in this article is for educational purposes only.

Please read our complete legal summary for more information on the legalities of distillation. Kyle Brown is the owner of Clawhammer Supply, a small scale distillation and brewing equipment company which he founded in 2009. His passion is teaching people about the many uses of distillation equipment as well as how to make beer at home. When he isn’t brewing beer or writing about it, you can find him at his local gym or on the running trail.

How long should I let my beer ferment?

I see fermentation duration questions a lot in forums and homebrewing Facebook groups. It’s not necessarily a one-size-fits-all answer, but there are simple guidelines to follow, especially if you want to err on the side of caution. Beer fermentation time is largely dependent on the beer style.

Just to preface this article, a beer’s time to ferment versus time spent in a fermentation vessel are two separate questions with different answers. The short answer: Although most ales ferment in 2-5 days, I always recommend you wait at least 2 weeks before moving to bottles/kegs for the best results.

Lagers on the other hand ferment in 2-3 weeks followed by several weeks or even months to condition. Lagers require a much more rigorous and extended fermentation schedule. Lagers also ferment at much cooler temps (45-55°F.) I’ll be honest, I’ve never actually brewed a lager because I don’t really drink them.

How do you know when to stop fermentation?

When is the Fermentation Over? – The fermentation is considered done when you either reach your desired sugar level or go “dry” at 0° Brix. A wine with 0.2% residual sugar contains two grams of sugar in a liter of wine. Dry wines are typically in the 0.2%-0.3% range, off-dry wines in the 1.0%-5.0% range, and sweet dessert wines are normally 5.0%-10%.

• However this can be a little subjective on taste and a wine with,5% or 5 g/L may taste completely dry depending on the wine.
• In the end there is no “correct” sugar level for your wine, it just comes down to your personal preference.
• Creating a dry wine Fermenting to dryness simply involves letting the yeast continue the fermentation until all of the sugars have been consumed.

If a secondary malolactic fermentation (MLF) is desired, no SO2 is added and ML bacteria are added to the wine (see our Guide to Malolactic Fermentation ). If no MLF is desired then the wine is immediately sulfited (with a thorough stirring) and we proceed to the ageing period (see our Guide to Tasting and Adjusting during Ageing ).

Ferment to dryness, sweeten later: Prior to starting fermentation, a small percentage of the refined and sulfited must can be set aside and put in the freezer (A zip-lock type freezer bag works great for this- remember to squeeze all the air out before sealing it to limit oxidation). This reserved must will be used to sweeten the wine before bottling and is called the “sweet reserve”. The rest of the wine is fermented to dryness. Whenever the wine is to be bottled, the sweet reserve is taken out and added to the dry wine until the desired level of residual sugar has been achieved. A bench trial will help determine the ideal ratios to add (see our Guide to Bench Trials ). The wine is then filtered and bottled (see our Guides to Filtering and Bottling ). Note: household sugar can also be used to sweeten the wine, but depending on the amount used the flavor in the final wine will not be as rich as if you used the original juice. Stopping fermentation before dryness: Once the desired sugar level has been reached the wine is sulfited in the fermenter (with a final stir to distribute the SO2) and immediately chilled to 40° F or below. Depending on how exact you want to be with your chosen RS% level, you may want to start the cooling a little earlier than right when the must is at the desired sugar level. Yeast will still be consuming sugars as they are being chilled. When they finally do get cold enough to stop being active, you may find you have a lower °Brix level than you wanted. To avoid this scenario start cooling 1-2° Brix higher than where you want to end up. Whenever the wine is deemed ready it is filtered and bottled. Note: An active fermentation can also be stopped by adding spirits to the wine, as in Port winemaking. However, unless you are after this kind of specialized winemaking, the added alcohol will make your wine very out of balance and this technique is not recommended for making non-fortified wines with residual sugars.

Is it possible to ferment beer too long?

It’s happened to the best of us. You brew then get busy and totally forget about bottling your beer! You may think it’s no good and should toss it, but hold a sec! We break down how long is too long in this week’s episode. So let’s paint a picture, you brew an awesome Mr.

1. Beer recipe, but then life gets busy.
2. You forget you brewed a batch and then one night you’re sitting there and you realize that your beer has been sitting there for 4 weeks! It’s happened to all of us.
3. Things come up and bottling your homebrew is just not a priority at the moment.
4. A common question we get is from people that have left their beer for to long and are thinking about dumping it.

Before you ever dump your beer always try it. You may think something is bad but when you taste it you could be surprised. It could be totally fine, or if you did get some type of infection it could be a good one that turns your beer into a nice sour! For brewing with Mr.

Beer, we always recommend that you bottle your beer no later than 24 days in the fermenter. You can go longer but the longer your beer sits the more chance you have to get an infection and get off-flavors in your beer. The 24-day mark has always worked well for us. We have gone over in some cases but mostly by a few days.

If I had to put a date on it, I would say you want to bottle your beer around 28 days, or if you cannot bottle it then you would want to rack it into a secondary fermenter to get it off the yeast. The main reason you want to get your beer off the yeast is due to Autolysis.

This happens when the yeast cells die and rupture they release several off-flavors into your beer. So getting your beer off the dead yeast will help prevent those flavors from happening. When you have a brew that has succumbed to Autolysis it will have this burnt rubber taste and smell to it and will most likely be undrinkable.

At that point, you would want to toss it. Now I do want to note that you can keep beer in the fermenter for longer. When you have healthy yeast and good temperatures your beer can sit longer and be fine but the longer it goes the chances of infection will increase.

What does healthy fermentation look like?

This is a question that we get quite often so we wanted to provide some information so you can tell if your brew is good or not. When you are new to brewing the first time you see the fermentation process it can look a little crazy. Each batch you brew will behave and ferment differently than the batch before, so it is possible that your fermentation will always look different.

1. Some people will dump perfectly good beer thinking it has an infection when it does not.
2. So before you decide whether your beer is a dumper, you will want to visually inspect and possibly even taste it to make sure it’s still worth keeping or not.
3. So let’s talk about what fermentation looks like.
4. During fermentation you will get foamy bubbles on the top of your beer, this is called krausen and is perfectly normal for brewing.

Depending on the batch that you are brewing you may get a very high krausen or a low krausen. Some beers might now show much of krausen at all. This all depending on what you are brewing, the ingredients you are using, temperature, etc. One way to always check for fermentation is to see if you have any trub build up on the bottom of the fermenter.

If you do, then your good to go. So just remember that all fermentations will not look the same. Okay so now onto how to spot an infection. An oily sheen on top of your beer that may look kind of like thin white ice sheets with jagged edges is a sign of the beginning of an infection. This infection is usually caused by wild yeast such as Brettanomyces or wild bacteria such as lactobacillus.

In some cases, it could be a combination of these or other bacteria/wild yeast. In more advanced infections, this layer of biofilm called a “pellicle” may look very wavy, sort of like ramen noodles. Or it may look like bubbles with webbing coming off it.

These are different types of infections, but they are caused by similar bacteria/yeast strains. A pellicle is only formed in the presence of oxygen and is a way for the wild yeast/bacteria top protect itself from oxygen because they prefer an anaerobic environment. So you can still have an infection even without the pellicle formation if your beer was free of oxygen exposure during fermentation.

In this case, the only way to know whether it is infected or not is to taste it. Don’t worry about getting sick because none of these wild bacteria, yeast or mold can harm you. If the beer tastes bad or rancid, you might wanna dump it. But in some cases, an infection can result in a pretty good tasting beer.

1. Eep in mind that sour beers, which are all the rage right now, are brewed with these wild yeasts and bacteria.
2. If you are brewing with our LBK and you consistently get infections it is possible that it got into some small scratches or the plastic of the fermenter.
3. In this case, we would recommend replacing your fermenter with a new one.

If your beer is infected with mold, which will be fuzzy and discolored (usually green but can be white or brownish – but always fuzzy), this can typically be skimmed off the beer. Mold only grows on the surface and will not penetrate the beer itself. Mold cannot survive the alcohol in beer.

1. Fortunately, mold usually takes a long time to grow on beer so as long as you’re not leaving it in the fermenter for too long, you shouldn’t have this issue.
2. Proper cleaning/sanitizing, and the proper care of your plastic equipment (only soft cloths for cleaning, nothing that can scratch the plastic) will help prevent these types of infection.

But always keep in mind that even with the best cleaning and sanitizing procedures in place, you can still get infections from time to time. Don’t let this discourage you. Learn from it and keep brewing.

How long is too long for fermentation?

If you are a homebrewer and have been concerned with just letting your beer batch sit in primary or secondary fermentation, this blog post will give you an answer to how long you can let it sit for without any issues. How Long Can I Leave My Beer in the Fermenter? Among most homebrewing enthusiast it is generally considered ill-advised to leave your beer for more than 4 weeks in primary or secondary fermentation.

Can beer ferment in 7 days?

If you are like me the hardest part about homebrewing is waiting for the beer to ferment. It can seem like ages before you get to bottle and then actually drink it! So, I thought it would be a good idea to break down how you can ferment your beer in 7 days.

• The key to doing this is to have your brewing process dialed in to be exact and you need some extra brewing tools.
• First, you need to make sure you are using clean and appropriate water for homebrewing.
• If you are using tap water for example that will have some extra chemicals in it.
• Those could cause some slight off-flavors in your brew which may take a little longer than 7 days to ferment out.

Next, you need to make sure your temperature is on point. Now, this does range depending on the yeast you are using. For example, with our standard Mr. Beer yeast, we have found that the ideal range is right around 72 degrees. It does well a little warm and ferments fast.

• So check the recipe you are brewing, what yeast it is, and make sure you can hold that temperature consistently during the brewing process.
• Regarding temperature, you also need to make sure that your wort is at the proper temperature as well before you pitch your yeast.
• This will help the yeast propagate and fermenter better.

Another factor that will help is that you need to make sure all of your brewing equipment is thoroughly cleaned and sanitized. So if you have all the steps in the brewing process down to a science then you need something to check your brew so you know when it is done.

There are a few things you can use for this. I have some people use the Tilt which connects to an app on your phone to let you know once your beer is done. But if you don’t feel like spending the money you can also use a good old fashion Hydrometer. When you first make your wort and before you pitch your yeast you will take a reading and this is your original gravity.

As the yeast eats the sugars in your wort the gravity will decrease. The way to know that your beer is done fermenting is that your gravity will not change within a 24 hour period. So for example, if you want to ferment for 7 days, you will take a gravity reading on day 6 and if that reading is the same on day 7 then your beer is done and ready to bottle.

With the proper equipment and a dialed-in brewing process, you can ferment a beer in 7 days. A little side tip for you. If you brew your beer in 7 days and you try one after carbonating and conditing and it tastes a little off, then it needs to condition longer. If you have any off-flavors in your brew we recommend letting the bottles sit at room temperature for an additional 7 days and then try one and see how it tastes.

Repeat this process until the off-flavor in your beer is gone. Cheers Robert

Will bubbling stops once fermentation done?

I started a batch of Merlot, it has been in the secondary fermenter under airlock for the last month. It is clearing very nice. How do I determine when the fermentation is done? Thanks, Brandon —– Hello Brandon, Thanks for the great question. Knowing that your fermentation is done before moving forward in the winemaking process is important.

• If the wine gets all the way to the point of bottling, and the fermentation has not finished, one of two things can potentially happen: either the wine corks will begin to pop out of the wine bottles ; or worse yet, if the corks are very snug, you could have bottles exploding.
• During a fermentation sugar is being metabolized into both alcohol and CO2 gas.

This gas is the same stuff that puts the fizzy in beer, soda pop and champagne, and it’s also the stuff that comes through the airlock and creates the bubbling action. A lot of beginning winemakers will use the airlock to make a determination. They see that the airlock is not longer bubbling and figure this is when the fermentation is done. It is very possible for a fermentation to stop and start back up again sometime later. This is known as a stuck fermentation, It is usually caused by some environmental change that the wine yeast does not like – temperature being the most common factor.

The important thing to know is that it is possible to bottle a wine that has stopped bubbling and have it start fermenting again after bottling – in the bottle! This CO2 has no place to go and builds up pressure in the wine bottle and well there’s-your-trouble. This begs the question, if the bubbling action through the airlock is not a solid indicator as to when a wine fermentation is done, then what is? The key to all of this is knowing if there’s still sugar in the wine must.

If there is then there’s still a potential for more fermentation. Fortunately for us winemakers, there is an easy solution. Use a wine hydrometer. A wine hydrometer is what can tell you if there’s still sugar in the wine must. It’s very simple to use and gives a reading instantaneously. By learning how to use a wine hydrometer, you can assure yourself that you will never bottle a wine too soon. You will be able to determine in moments where your fermentation stands. You may be asking yourself at this point, “What if I want sugar in my wine”? If you like your wine with some sweetness to it, not a problem.

Learn about making sweet wines on our website. It’s simple enough to do. You just have to know how to do it properly. Brandon, hope this information helps you out. The hydrometer is the answer to the question: when is a fermentation done ? Happy Winemaking, Ed Kraus —– Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E.C.

Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.

Why does fermentation stop at 15?

Fermentation is the process in winemaking where sugar converts to alcohol. This is where we turn grape juice into an alcoholic beverage. Back in the 1800’s, Louis Pasteur noticed that there was a connection between yeast and fermentation. He recognized the process where the yeast acts as the catalyst through reactions that convert sugar into alcohol.

During fermentation, winemakers have to consider several factors, including sugar content, yeasts, temperature and cleanliness. Sometimes fermentation is done in stainless steel tanks, sometimes it happens inside a wine barrel, sometimes in large wooden vats. In sparkling wines, fermentation even happens in the bottle itself.

During this part of the process, yeasts take the sugars present in the grape juice and turn it into ethanol and carbon dioxide. A key job of a winemaker is to work with a yeast that lives long enough to convert all the sugars into alcohol and CO2. Leftover sugar leads to wines that are too sweet – not balanced. Yeasts Some winemakers use a yeast starter to kick off fermentation. Yeasts are tiny organisms that reproduce through cell division. Winemakers have nearly 2,000 species of yeast to choose from for fermentation. Most winemakers use the yeast called Saccharomyces Cerevisiae.

There are hundreds of other yeasts that can turn grape juice into wine, but can be trickier to use to avoid off flavors. Yeast stops its work during one of two moments – either after all of the sugar in the must has been converted or when the alcohol content reaches 15% alcohol. Fifteen percent is a concentration strong enough to stop the activity of almost all yeasts.

Temperature The temperature of the yeast starter and the must is vital to the success of the wine. Winemakers need to control the heat that’s generated during fermentation. Depending on the kind of wine, fermentation occurs within different temperature ranges.

Lower temperatures mean that fermentation happens more slowly. Higher temperatures can mean a fast fermentation. This can result in killing off your yeasts too early or a “cooked” flavor. Warmer fermentations are usually used for red wines for increased color and tannin. Temperature is key to making sure the chemical processes go ahead as planned.

White wines should be fermented between 64 and 68 degrees F. Red wines can be fermented up to a balmy 85 degrees F. Sometimes, controlling this temperature means that winemakers have to cool their vats. They do this by using built-in cooling systems in their fermentation tanks or like back in France, surrounding the vats with ice.

Cleanliness More than at any other time of winemaking, cleanliness is key during fermentation. Containers and tools need to be sterile during this process. Any additional bacteria can completely derail the fermentation process. Punch Downs and Pump Overs After the yeast is added, carbon dioxide is released during fermentation.

For red wine, this means the skins float up to the surface. Winemaker call this “punch down” or “pump over” to keep the skins soaking in the juice. All the skins and juice is pressed after fermentation is complete. Then it’s racked and aged in barrels. Depending on how strong the force, pump overs extract the tannins in a wine.

Some agitate the wines aggressively and some are gentle sprinklers. In larger vats, pump overs also add oxygen to the mix. Punch downs are a much gentler way to stir in the skins. Punch downs keep the grape skins from pulling out too many tannins. The small amount of oxygen that’s added to the fermentation slows the process.

Fermentation stops when the yeast has either consumed all of the sugar in the must, or the alcohol level has gotten too high for the yeast to survive (that magical 15%). This is one reason that it’s important to know the sugar level of the grapes before fermentation.

Why is my beer still fermenting after 2 weeks?

Has my beer stopped fermenting? This is a common question that crops up amongst new brewers waiting expectantly on their first or second batch of beer. Fortunately it’s an easy question to answer -and a good opportunity to learn what happens during fermentation as well as a bit about using hydrometers.

• Read on! Firstly it’s a good idea to know what to expect of a fermenting batch of beer.
• Most of us know that there should be some vigorous bubbling from the airlock (much to the amusement of family members), and a thick head of yeast on top of the beer.
• This will slow down and eventually subside after a few days, signifying that the time for bottling is soon approaching.

But what is really going on under that lid? To understand what’s really happening in the fermenter we need to understand the basics of what our yeast get up to. These friendly fungi are the ones actually making our beer for us at this point, so their habits and happiness is worth understanding.

1. When pitched to the fermenter, the yeast first acclimatise to their new environment and begin to multiply many times over.
2. The yeast use oxygen during this reproductive phase and this is the reason that brewers shake the fermenter vigorously for several minutes to oxygenate the wort before pitching the yeast.

The yeast do not yet make any alcohol or carbon dioxide at this early stage -they are far too busy populating the contents of the fermenter! This quiet start is referred to as the lag phase and is where we expectantly wait for 12-24 hours for the yeast population to grow, and then begin on the important (and rowdy) task of producing alcohol! Well that’s pretty simple- but you guessed correctly that if the wort is not oxygenated the yeast won’t be able to multiply.

This can happen if a brewer forgets to oxygenate or doesn’t shake the fermenter quite enough ( 4-5 minutes is best), Another important factor is just how much yeast is pitched. A left over half sachet from a few months ago is not going to get the job done! There need to be enough healthy, viable yeast to get off to a strong start populating the wort.

Too few simply cannot multiply enough times. So.always pitch a full rehydrated yeast sachet. The lag phase will be short and the yeast happy and plentiful! The next phase is the vigorous conversion of sugars to alcohol and carbon dioxide. The yeast have run out of oxygen and now turn to sugar for sustenance.

• They can survive without oxygen and enter a new phase known as ‘anaerobic’ (without oxygen).
• The yeast now produce alcohol, flavour compounds called esters and phenols, and work their way through the sugar.
• The carbon dioxide simultaneously produces a large head of yeasty froth on top of the beer and signifies the peak of fermentation.

This busy and productive time is also commonly called ‘primary fermentation’ and is essentially when the magic happens and the young beer is created. Once the primary fermentation has begun in earnest there is not too much that can dissuade the yeast from quitting-excepting really cold conditions- below 16C say.

As a general rule the cooler temperatures result in slower (and perhaps less energetic) primary fermentation times and warmer faster. Often this stage is over very quickly- two to three days is not uncommon with 4-7 being average. But it’s not quite over yet. The last phase of fermentation is where our original question usually arises.

Is the beer almost ready? -What is it doing now?-Should I bottle it this weekend? I’m getting thirsty! After the initial crescendo of primary fermentation, the beer can look like it has completed its job. This is not at all true though. The young beer has now entered its last important phase known as secondary fermentation.

1. At this point the yeast are still consuming any remaining sugars- though at a much slower rate – and also consuming by-products of the primary phase.
2. The yeast is finishing the job thoroughly and also cleaning up after itself! With the sugar almost gone, the yeast finds and breaks down various other compounds which later affect the finished flavour of the beer.

You could see it a gradual finishing or pre- maturation phase. Once the yeast has exhausted its supply of food it begins to go dormant. It clumps together and drops to the bottom of the fermenter, eventually leaving the beer clear(a process called flocculation) English brewers refer to this as the beer ‘dropping bright’,Depending on the yeast this can happen quite quickly or sometimes take a while.

The fermentation is essentially now over, and the beer is beginning to mature. So is my beer ready? Typically, yes, but let’s look at some important time frames and scenarios. Being aware of variables is what is important now. Most advice to home brewers suggests a total fermentation time of 12-14 days.

This is assuming a ‘textbook brew’ with plenty of healthy yeast and fermentation at a suitable temperature ( 17C-24C ). Generally things work out fine within this timeframe and temperature range. The beer is then bottled, undergoes carbonation from a small secondary fermentation (from added priming sugar) and then has a week or three to mature before drinking.

Now that you have a general idea of what’s going on under the lid let’s quickly look at how a hydrometer can help us measure the yeast’s progress, and help calculate the alcohol content of our finished beer. A hydrometer is a useful floating measure that will sink lower or float higher depending on how much dissolved sugar is in our beer.

Most brewers take a gravity reading just before the yeast is pitched, and then again before bottling. As the yeast consumes the sugar, the hydrometer readings will gradually drop (as the hydrometer floats lower). Generally, taking a reading during fermentation is quite unnecessary if things are progressing normally.

Remember, frequently opening your fermenter exposes the contents to bacteria and wild yeast, though if you have a side tap this is a bit less of an issue. There is a good bit of common advice that if one takes a reading for a few consecutive days and gets the same results, the yeast has finished the work –though again this typically this isn’t necessary unless you really aren’t sure.

Measuring the alcohol content is done by taking (and writing down!) a gravity reading just prior to fermentation called the Original Gravity (shortened to O.G.), and then, at the end of fermentation the Final Gravity (F.G.). The F.G.is subtracted from the O.G.

• And multiplied by 0.129 to give the Alcohol by Volume (the same %ABV we see on our commercial beer and wine bottles).
• Here are three examples of some typical strengths of beer, beginning with an average strength.
• Average: O.G.1.048 F.G.1.011.1.048-1.011=0.037 37 X 0.129=4.77% A.B.V.
• Light : O.G.1.034 F.G.1.008 1.034-1.008=0.026 26 X 0.129=3.35% A.B.V.

Strong : O.G.1.069 F.G.1.014 1.069-1.014=0.055 55 X 0.129=7.09% A.B.V In another post I will take a more detailed look at using a hydrometer, but that’s a useful start for now! To round up, let’s quickly look at where a fermentation cycle can go astray, take too long or just seem wrong – and why.

By now you now have a pretty clear idea of the fermentation phases happening inside fermenter as well as some of the possible pitfalls. Here’s a set of easy ‘Best case’ versus ‘Concerned! ‘scenarios to help you! The lag phase: Best case scenario: A full sachet of rehydrated yeast s pitched and begins to ferment (bubbling airlock) after 6-12 hours (or even sooner).

The temperature is within target range specified on sachet (or manufacturer’s website)The wort was vigorously shaken and splashed to aerate it thoroughly. A light froth begins to form on the beer. The lag phase. Concerned! : After 24 hours nothing is happening or there is only very occasional bubbling from the airlock.

Check that the airlock is properly secured- often a slight leak in the airlock’s grommet seal stops it from bubbling as the CO2 is escaping around it.17C to 24C is your ballpark. A quick peak in the fermenter may reveal an actively fermenting beer! Is the fermenter sitting in an icy winter garage or is the temperature really low? Keep the fermenter in a warm enough room.17C to 24C is your ballpark. Did you aerate enough (or possibly forget)? If not, do so immediately- it should help get things going. Under-pitching(not enough) yeast will also slow things down considerably. Consider pitching more yeast. Slow bubbling does mean something is happening – often it will simply get going properly in another few hours. If you have checked through the variables, grab a beer and don’t worry.

Primary Fermentation: Best case scenario: A rocky head of yeast forms on the beer and the airlock is happily bubbling away. Regular bubbling slows right down after three to six days (sometimes sooner), A foam line can be visible from the high ‘krausen’ on some fermenters.

Cold temperatures are your main cause for concern here if the other factors like yeast and aeration have been checked. Move the fermenter to a warmer area. Warm temperature and a low gravity beer can lead to very quick fermentations- as short as 2-3 days. Primary fermentation may have already taken place.

Secondary fermentation. Best case scenario: The airlock slows down to a very occasional bubble. The surface of the beer clears with a few light patches of thin foam here and there. Many brewers use the airlock as an indicator at this point-once activity stops completely the beer is done.

• This works pretty well, just be aware that a very cold spell can also make your yeast go temporarily dormant! At this stage the beer begins to clear of yeast, and after a few days the yeast should have formed a thick visible layer at the bottom and the beer cleared.
• At this time you can bottle within a few days or let it mature for another week or so if you do not have time.

Remember; two to three weeks are the best length of time to wait before bottling. Secondary fermentation. Concerned! : The beer smells ‘off’ or the airlock is persistently bubbling.

A bad smell (and there are many kinds!) or a visible growth on top of the beer means that wild yeast and/or bacteria have got in and wreaked havoc. Pay more attention to sanitizing. It’s not common, but it does sometimes happen-quite often more in summer or autumn when there is a lot of wild yeast floating around. A ‘green apple’ smell is normal for young beer, and a light sulphur smell is also known with some yeast strains. A persistent fermentation can mean two things. Most probably the yeast is simply taking longer to get the job done or, less likely, wild yeast and bacteria have taken residence. Most likely it is the strain of yeast that is simply taking a little longer than usual. If in doubt have a sniff in the fermenter. It should smell initially of carbon dioxide followed by a clean beer/hoppy/slight green apple aroma. If in doubt, a gravity reading will help.

With a little experience and the information here, you will soon always know when your beer is ready. And it’s a very satisfying thing to know too-good luck with your brews! This article is copyright and used with exclusive permission to Beerlab. Nick Birkby 2013 : Has my beer stopped fermenting?

What does a bad ferment look like?

An Unsafe Ferment: –

Visible fuzz, or white, pink, green, or black mold. Get rid of it. This means your ferment was exposed to too much oxygen, bad bacteria was introduced during preparation, or it was too warm. Either way, it shouldn’t be consumed. Extremely pungent and unpleasant stink. This differs significantly from the normal smell of fermented veggies. We had a jar of sauerkraut go bad once in our early fermenting days, and while it looked perfectly fine from the outside, the smell quickly told us it was no good. If it makes you want to gag, discard the whole thing and sanitize your jar. Slimy, discolored vegetables. While bright color changes frequently occur during fermentation, very brown or slimy vegetables are a sign of spoilage. (Note that green veggies like cabbage may brown and pale somewhat.) A bad taste. Remember, even though the taste of fermented veggies is unfamiliar to many of us, it shouldn’t be unpleasant. If the food tastes spoiled, spit it out!

How do you tell if my beer is infected?

The First Signs of a Pellicle – The first thing you’ll notice if your beer has developed an infection is an oily sheen that has suddenly developed on the top of your beer, This sheen can take various forms, but it is usually very thin and has a white tint.

Should you shake fermenting beer?

Home Distiller Production methods from starch to sugars. Moderator: Novice Posts: Joined: Sat Jan 27, 2007 9:37 am by » Wed Mar 28, 2007 8:26 pm Having fits,,convulsing while awaiting fermentation?. No. Sometimes, after racking a batch off, I’ll give the secondary a good shake or twelve.

This creates a much more vigirous reaction out of the air-lock. (in my ignorant thinking this is making more alcohol in a shorter amount of time) I’ll keep this shaking up for about 20-30 mins. That’s about as long as my forearms will allow me. It is really not shaking, rather a swirling motion I give the carboy(roomies have dubbed this activity “the moonshiners boogie” and I’ve since been writting the song to be posted soon) This does seem to give the brew a more active ferment.

My brew buddies, however, urge me not to do this. (they think I’m making beer and this will effect the flavor of the beer greatly) Technically, I am making beer, though my end result is much stronger than thiers. So, I’ve come to you guys (once again) for advice.

Do I continue my “boogie”ing or am I just wasting time and energy? Again, I do this only following a racking so I do not plume up any unwanted sediment back in to the solution that I’ve waited so long to get out. Secondly, if this swirling does increase ferment time, I wonder what would happen if you were to place ferment vessles on some sort of vibrating machine that made this motion continuosly(wonder if the Mrs.

would miss her toy) Like a modified paint shaker or something of the like. Just a late nite inquiry. -Peace “Indulge in that alchemy in which hard cash is transformed into a soft liquid of such potency that even the insolvent becomes dissolved!” -P.D.Q.

Bach Trainee Posts: Joined: Tue May 03, 2005 8:38 am Location: great white north by » Wed Mar 28, 2007 8:48 pm Once you put it to ferment leave it alone to do it’s thing. If you shake it or stir it and introduce o2 you only slow it down. Leave it be, when the bubbles stop it’s done. Give a man a fish and he will eat for a day.

Teach a man to fish and he will sit in a boat all day and drink beer. Swill Maker Posts: Joined: Wed Aug 09, 2006 1:29 am Location: Perth, Aust. by » Wed Mar 28, 2007 9:05 pm I would say that the dissolved co2 from the wash is coming out when you shake it, making it appear like more bubbles are forming.

• Can’t see it making much difference to end result tho Rumrunner Posts: Joined: Sat Mar 04, 2006 1:42 am Location: Nth coast NSW by » Thu Mar 29, 2007 4:15 am I reckon that if you keep the yeast in suspension and the dissolved CO2 to a minimum, the rate of ethanol production might increase.
• You’d have to make sure your airlock didn’t let in any air.

A magnetic stirrer may be an option. Swill Maker Posts: Joined: Wed Aug 09, 2006 1:29 am Location: Perth, Aust. by » Thu Mar 29, 2007 4:18 am I would have thought that dissolved co2 would help, as it drops the pH a little. Rumrunner Posts: Joined: Sat Mar 04, 2006 1:42 am Location: Nth coast NSW by » Thu Mar 29, 2007 4:42 am rangaz wrote: I would have thought that dissolved co2 would help, as it drops the pH a little.

1. It’s also one of the waste products like ethanol so I presume reducing its concentration would help.
2. But what would I know – I’m only an apprentice! Novice Posts: Joined: Sat Jan 27, 2007 9:37 am by » Thu Mar 29, 2007 8:51 pm Interesting responses,.
3. Thanks! ( I knew I liked this forum) First, I only shake ferments just after airlock is added, and no sediment present.

This airlock is a standard plastic air-lock, fitted trough a rubber bung found at any brew shop. Second, during the racking process, I believe(pardon the ignorance), the co2 being released creates preasure inside the vessel, preventing any/most O2 from entering.

(not to mention the fluid filling the vessel) I doubt any O2 is getting in there, allthough I’ve ebeen wrong before. Third, I should not try to post here so late in the drinking hour. If this was to increase ferment time though,, Thanks -Peace “Indulge in that alchemy in which hard cash is transformed into a soft liquid of such potency that even the insolvent becomes dissolved!” -P.D.Q.

Bach Angel’s Share Posts: Joined: Tue Jan 30, 2007 2:47 pm Location: desert mountains of the west by » Fri Mar 30, 2007 9:25 am there are some advantages to shaking and stirring in that you can prevent stratification in the fermenter. degassing will also help drag the equilibrium to toward completion.

Does it hurt to leave beer in fermenter too long?

Homebrewing beer can be a rewarding experience for beer enthusiasts, but sometimes the time to produce that one perfect gallon of beer can be difficult to pace. You know that it’s important to avoid under-fermenting your beer, but is it possible to over-ferment? Homebrew beer cannot over-ferment because once the yeast has consumed all sugar, fermentation will end, a process that normally takes between 1-3 weeks.

Can I bulk ferment for 12 hours?

by Tom Cucuzza – The Sourdough Journey (c) January 2023 Why do some sourdough recipes call for a 30% rise and others a 100% rise? One of the great mysteries of sourdough baking is why some recipes recommend a 30% rise and others recommend up to a 100% rise during bulk fermentation.

Both methods produce very similar results. How is this possible? The difference is due to the dough temperature during bulk fermentation. I have reviewed and tested dozens of recipes and there is a clear correlation between the target bulk rise, and the bulk fermentation dough temperature. Recipes calling for a warm bulk fermentation temperature (e.g., Tartine at 80F/27C) recommend a low percentage rise (30%), while recipes calling for a cool bulk fermentation temperature (70F/21C) recommend a higher percentage rise (75-100%).

The reason is because the dough keeps fermenting in all of the downstream steps after bulk fermentation, until the loaf is baked. Consequently, warm-fermenting dough needs to be cut off earlier in bulk fermentation than cool-fermenting dough. With warm-fermenting dough, you need to “hit the brakes” at a lower percentage rise to prevent the dough from overproofing in the shaping and final proofing steps. Measuring the dough temperature and percentage rise is the most accurate and repeatable method of determining the end of bulk fermentation. But, the dough temperature and percentage rise are inextricably linked. A 100% rise at 70F/21C produces a much different result than a 100% rise at 80F/27C.

The percentage rise alone is a meaningless data point without also knowing the dough temperature. The approximate timing is provided here as a reference, but it is a weak predictor of when bulk fermentation should be cut off. The percentage rise does not lie! You can bulk ferment at any dough temperature, but the combination of dough temperature and percentage rise are the secret to perfect, predictable, and repeatable sourdough fermentation.

But you must measure both. Everyone’s starters and flours are different so your results may differ from these guidelines. If you overproof your dough at these recommended targets, then the next time you bake, reduce your target rise by 10%. If you underproof, then increase the target rise by 10%.

1. By carefully measuring and keeping records of your dough temperature and the percentage rise, you can dial in the optimal target rise within a few bakes.
2. Once you find the right percentage rise for a specific dough temperature, it never changes for that recipe.
3. Continue reading for more important details and examples! PART 1: UNDERSTANDING THE INTERPLAY OF DOUGH TEMPERATURE AND PERCENTAGE RISE To best understand the importance of properly cutting off bulk fermentation, one must consider the entire fermentation chain.

The “end” of bulk fermentation is the “beginning” of the downstream steps in bulk fermentation. The dough temperature and percentage rise at the end of bulk fermentation determine how the dough behaves throughout the remaining steps until it is baked. The Setup for the Fermentation After “Bulk Fermentation” When bakers decide to cut off bulk fermentation, they may believe that somehow the dough hears that message and stops fermenting. It does not. In fact, the dough keeps fermenting at the same or faster rate until the dough temperature cools down to refrigerator temperature (37F/3C) which can take 8-12 hours! Note: This example assumes a cold retard in the refrigerator after shaping, but the same principles apply with countertop proofing at room temperature.

1. The end of bulk fermentation is the beginning of the fermentation “glide path” from shaping until the yeast die-off point during baking.
2. Your decisions and actions at the end of bulk fermentation determine how all the remaining steps will play out.
3. The Downstream Fermentation Steps When a baker cuts off bulk fermentation, this is an arbitrary cutoff point we create in our minds, but the dough keeps fermenting! · During the 40 minutes of pre-shaping, bench rest and final shaping, the dough keeps rapidly fermenting,

Warm dough (80F/27C) can increase in volume by at least 10% during this time. You don’t see this rise because you are handling and shaping the dough, but it is rapidly fermenting. The dough temperature at the time of shaping determines how rapidly the dough will ferment during this 40-minute period.

· When you place your shaped dough in the refrigerator for a cold retard, it can take 8-12 hours for the dough to reach “hibernation” temperature of 37F/3C. During that long cooldown, the dough continues to ferment, particularly in the first few hours when the dough is still above 50F/10C. The dough temperature, when it enters the refrigerator, determines how fast and how much the dough will continue to ferment throughout the cold retard.

· Lastly, as the dough warms up again in the oven during the initial phase of baking, the fermentation process reactivates until the dough temperature reaches the yeast die-off point of 130F/54C during baking in the oven. Experienced bakers always pace their fermentation to leave a little “gas in the tank” for the final burst of fermentation in the oven.

• We will focus primarily on what happens during shaping and the cold retard.
• See Appendix 1: What Happens in the Oven During Baking? for more information on that topic.
• The End Point – The Perfectly Fermented Loaf Every baker’s goal is to have every loaf end up in the same place – a perfect, fully fermented loaf.

You can bulk ferment at a wide range of temperatures, but you need to synchronize your bulk fermentation percentage rise with your dough temperature for optimal results. The key is understanding how your actions at the end of bulk fermentation influence all of the downstream fermentation steps.

1. PART 2: DOUGH TEMPERATURE DETERMINES THE FERMENTATION SPEED As you approach the end of bulk fermentation, you want to focus on two questions: 1) How much has the dough risen? Your dough readily shows how much it is fermenting by the rise in the dough.
2. The percentage rise determines how far along the dough is in the fermentation process.2) What is the dough temperature? Sourdough fermentation is a highly temperature-sensitive, biological process.

Warm dough ferments much faster than cool dough. The dough temperature determines the fermentation speed, Warm Dough (80F/27C) in the Downstream Steps If you are following the Tartine method, for example, and bulk fermenting your dough at 80F/27C dough temperature to a 30% target rise in the dough, consider what happens after the end of bulk fermentation.

After bulk fermentation, the dough spends 40 minutes at room temperature during the shaping steps. During this time the dough is continuing to rapidly ferment, and the yeast population is rapidly reproducing. You do not typically see this rise during shaping because you are handling, shaping and de-gassing the dough – but it is happening.

If your dough remained unshaped for 40 minutes after the end of bulk fermentation you would see it rise at least 10%, sometimes more. So, a 30% rise at the end of bulk fermentation continues to at least a 40% rise before the dough goes into the refrigerator.

After shaping, the warm, shaped dough goes into the refrigerator for the cold retard at a dough temperature of approximately 78F/26.5C (warm dough loses a few degrees of temperature during the shaping process). Many people mistakenly believe that the dough immediately approaches refrigerator temperature once it goes into the refrigerator.

It does not. The dough takes a long time to get down to refrigerator temperature – as long as 12 hours to reach a dough temperature of 37F/3C. During this time the dough keeps fermenting. Cool Dough (70F/21C) in the Downstream Steps If you are following a recipe that calls for cool bulk fermentation at 70F/21C (or lower), these recipes often call for a 75% (or higher) rise at the end of bulk fermentation.

1. Let’s assume 75% in this example.
2. The difference between 70F/21C and 80F/27C may not seem like a lot, but the fermentation rate at 70F/21C is about 50% slower than the fermentation rate at 80F/27C.
3. In other words, warmer dough is fermenting and rising almost twice as fast as cooler dough.
4. Let’s call this the fermentation speed.

During the 40-minute shaping and bench rest, 70F/21C dough will rise only about 5% in volume, or half the fermentation speed of the 80F/27C dough. Warm dough rises at approximately 20% per hour and cool dough rises at approximately 10% per hour as each dough reaches the end of bulk fermentation. An Example: “Hitting the Brakes on a Slippery Road” If you were driving your car on a slippery road and you saw an upcoming stop sign, you need to assess your distance to the stop sign (i.e., how much more the dough needs to rise to be fully fermented), and your speed (i.e., how fast is the dough fermenting) to determine when to hit the brakes.

If you are traveling at 80 mph / 130 kph, you need to hit the brakes much earlier than if you are traveling at 40 mph / 65 kph. That speed difference is the equivalent of the difference in fermentation speed between 80F/27C and 70F/21C. Warm dough is fermenting almost twice as fast as cool dough – so, you need to hit the brakes earlier with warmer dough.

“Hitting the brakes earlier” means cutting off bulk fermentation at a lower percentage rise (e.g., 30%) because the dough is rapidly fermenting and it keeps fermenting in all of the downstream steps. At faster speeds, you need a longer stopping distance to avoid skidding through the stop sign – which would result in an over-proofed loaf.

• PART 4: WHAT HAPPENS IN THE REFRIGERATOR DURING A COLD RETARD? Once your shaped dough is placed in the refrigerator for a cold retard, the warm dough and cool dough continue to behave differently, and to complicate matters, cooling dough does not “show the rise” as visibly as bulk fermenting dough.
• Warm Dough (80F/27C) in the Refrigerator When you place warm dough in the refrigerator for a cold retard, the dough keeps fermenting until the internal dough temperature reaches about 37F/3C.

This can take up to 12 hours. Prior to that time, the dough keeps fermenting as the dough slowly cools through different temperature ranges. The following chart shows the cooling dough temperature in the refrigerator for dough that ended bulk fermentation at 80F/27C. How Does Warm Dough (80F/27C) Behave in the Refrigerator? Phase 1: 80F-70F / 27C-21C Dough Temperature in the Refrigerator – Rapid Fermentation It takes about 60 minutes for warm dough to cool down from 80F to 70F / 27C to 21C in the refrigerator. During this time, the dough doesn’t know it is in the refrigerator.

It keeps fermenting at the same pace as if it were on the countertop at room temperature. In this 60-minute time period, warm dough can continue to rise as much as 20%. You don’t see the rise as readily in the refrigerator because the dough was recently compressed during shaping, and the gasses in the dough begin shrinking as the dough cools down.

Have you ever put a balloon in the refrigerator? It shrinks. The dough is shrinking as it cools, but it also expanding as it ferments. The visible rise in the refrigerator is not exactly indicative of how much the dough is continuing to ferment, but I have done experiments on unshaped dough throughout the cold retard process to approximate the percentage rise that occurs in the refrigerator.

1. Phase 2: 70F-50F / 21C-10C Dough Temperature in the Refrigerator – Moderate Fermentation As the dough cools/ down from 70F to 50F / 21C to 10C, the dough keeps fermenting, but now at a pace slower than typical bulk fermentation speeds (due to the lower dough temperature).
2. It takes approximately 3 hours for the dough temperature to travel through this temperature range, and the dough continues rising approximately 10-20%.

It is difficult to see and measure this rise in a shaped loaf, but it is fermenting. Phase 3: 50F-42F / 10C-5C Dough Temperature in the Refrigerator – Slow Fermentation Once the dough reaches 50F/10C, the fermentation activity significantly slows down and it takes approximately 3 hours for the dough to travel through this temperature range.

1. There is generally no visible rise in the dough during this 3-hour period, but it is continuing to slowly ferment.
2. If your dough remains in this range (above 42F/5C) for more than 12 hours, it will likely overproof.
3. This occasionally occurs in the summer when refrigerator temperatures may be as high as 45F/7C.

Phase 4: 42F-37F / 5F-3C Dough Temperature in the Refrigerator – Very Slow Fermentation Depending on your refrigerator temperature, the dough takes another 6-8 hours to reach /37F/3C. The dough continues to rise and ferment very slowly during this phase.

1. If you are trying to build more sour flavor in your loaves, this is a good temperature range for longer fermentations.
2. Phase 5: 37F/3C Dough Temperature in the Refrigerator – “Hibernation” When the dough reaches 37F/3C, it is generally considered to be at the “hibernation” temperature.
3. The dough keeps fermenting, but extremely slowly.

You can keep your dough in the refrigerator for days at this temperature.24 hours in the refrigerator at 37F/3C is the equivalent of 30 minutes (maximum) of peak bulk fermentation time. Days at 37F/3C are the equivalent of minutes of fermentation at 80F/27C.

1. How Does Cooler Dough (70F/21C) Behave in the Refrigerator? When you load cool dough into the refrigerator, it behaves differently than warm dough, especially in the first 6-8 hours.
2. Phase 1: 80F-70F / 27C-21C Dough Temperature in the Refrigerator – Rapid Fermentation Because the dough enters the refrigerator at 70F/21C, there is no rapid fermentation phase at warm temperature.

This is a major difference between 80F/27C dough and 70F/21C dough in the refrigerator. Warm dough rapidly rises approximately 20% during the first hour in the refrigerator. Cool dough bypasses this phase. Phase 2: 70F-50F / 21C-10C Dough Temperature in the Refrigerator – Moderate Fermentation Cool dough enters the refrigerator at about 70F/21C, but it behaves differently than the warm-fermented dough at the same temperature.

Warmer-fermented dough typically has a larger, more active yeast population so it more vigorously ferments in this range. The optimal temperature for yeast production and re-production is 75-80F / 25-27C. The cool dough never hits this temperature range during bulk fermentation, so it never reaches its peak production or reproduction rate.

Phases 3-5: 50F-37F / 10C-3C Dough Temperature in the Refrigerator – Slow, Very Slow, Hibernation By the time the 70F/27 dough cools down to 50F/10C, it generally follows the same trajectory as the warmer dough down to 37F/3C. In this range, the fermentation rates are fairly similar.

PART 5: FERMENTATION CURVES AT DIFFERENT TEMPERATURES – AN ILLUSTRATIVE EXAMPLE Based on the information in the prior sections, we can construct an illustrative fermentation curve for 80F/27C dough and 70F/21C dough throughout the entire fermentation cycle. In this example, assume that all dough needs to theoretically rise to 100% to be fully fermented.

We know that we cannot visibly measure the percentage rise through the shaping steps, because of degassing, or in the refrigerator because the gasses shrink at cool temperatures. But if you imagine you could accurately measure the percentage rise throughout the process, this is what the percentage rise curves would look like over a 24-hour cycle. Cool Bulk Fermentation – 70F/21C Dough: Target Bulk Rise 75% A loaf bulk fermenting at 70F/21C may take 12 hours to reach a target rise of 75%. At the 75% rise, the dough is shaped, where it rises 5% more to approximately 80%. The dough then goes into the refrigerator where its rise curve flattens fairly quickly and it slowly rises to 100% over the next 12 hours.

Warm Bulk Fermentation 80F/27C Dough: Target Bulk Rise 30% A loaf bulk fermenting at 80F/27C ferments much more quickly. It reaches its 30% target rise in 5.5. hours of bulk fermentation. During the shaping process it rises another 10%. Within the first few hours in the refrigerator, it has risen to 75% – the same point where the cool loaf exited bulk fermentation.

In the final few hours of the cold retard, both fermentation curves converge, and the loaves end up at exactly the same level of fermentation. Cool dough requires a higher rise in bulk fermentation (75%) because it cools down and slows down quickly as it enters the refrigerator.

Warm dough starts faster and maintains a warmer temperature in the refrigerator. It continues its very vigorous fermentation rate for a few hours in the refrigerator. FREQUENTLY ASKED QUESTIONS What is the best temperature for bulk fermentation? You can bulk ferment at virtually any temperature between 50-90F / 10-32C.

The key is to synchronize the target percentage rise with your dough temperature. Warm dough requires a low bulk rise and cool dough requires a higher bulk rise. Why don’t I see the dough rising in the refrigerator? As your dough cools down in the refrigerator, the carbon dioxide gasses that inflate the loaf begin to shrink at low temperatures.

So the dough is still “rising” but it is shrinking at the same time. Once the loaf warms up in the oven during baking, the cool gasses expand and produce some of the explosive ovenspring that you see in the first 20 minutes of baking. Is the target bulk fermentation temperature the “ending temperature?” No.

It is the average (and ending) temperature. Bulk fermenting your dough is not like cooking a steak where you are trying to raise the temperature to a desired end point. Bulk fermentation works best if you can maintain your target temperature throughout bulk fermentation.

1. Use tools such as a desired dough temperature calculator and a proofing chamber to maintain a constant dough temperature throughout bulk fermentation.
2. Temperature fluctuations during bulk fermentation can result in uneven dough fermentation with some parts of the dough fermenting faster or slower than others.

The appropriate target percentage rise is more influenced by the ending dough temperature because that temperature influences the fermentation in the downstream steps. Bulk fermentation times generally are driven by the average dough temperature during bulk fermentation.

How do you accurately measure the percentage rise? Use a vessel with milliliter markers on it. Your starting point is the volume in milliliters after you have mixed all of your ingredients. Sometimes the dough is domed on top after mixing and it is difficult to get a good starting measurement. For most country loaf recipes (e.g., Tartine at 75% hydration and 20% starter), the initial starting volume of the dough is equal to 1.5x the flour weight in grams.

For example, a 500g flour-weight recipe typically mixes up to 750 milliliters of initial dough volume. You would then multiply this number times 1 plus the target percentage rise to mark your final volume target. For example, a 50% target rise would be 750 milliliters x 1.5 = 1,125 milliliters.

Many recipes call for the dough to double in volume and don’t specify the target dough temperature? I don’t recommend following those recipes. How can I learn more about this topic? I have dozens of videos on my YouTube channel at The Sourdough Journey on this topic. Here is a good place to start. When is Bulk Fermentation Done?: Episode 8 – Low and Slow,

You can also find more information on this topic at thesourdoughjourney.com If you find the information helpful, please support The Sourdough Journey at thesourdoughjourney.com/donate Appendix 1: What Happens in the Oven During Baking Once your loaves reach the oven, after a cold retard, there is still one last stage of fermentation that occurs in the oven. As your cold dough warms up in the oven, the yeast and lactic acid bacteria reactivate for a short, but powerful, “last gasp” of fermentation until the dough reaches the 130F/54C die-off temperature.

• In a typical bake where a cold loaf is loaded into a preheated oven and Dutch oven, the dough will rise to active fermentation temperature (70F/21C) in about 5 minutes and will continue very rapidly fermenting and producing CO2 for about 15 minutes until the dough temperature reaches 130F/54C.
• At that point, all fermentation finally stops.

For more information on this topic, check out the video, “The Secrets of Ovenspring and Baking Temperature.”

How long should I wait for fermentation to start?

Liquid Yeast – Liquid yeast can be added directly to the wort once the wort cools to a temperature below 80° F. You may decide to do a yeast starter, which is recommended for high gravity/alcohol beers. Read our Making a Yeast Starter article for more info. Here is how you prep an Activator pack:

To activate, locate and move inner packet to a corner. Place this area in palm of one hand and firmly smack package with the other hand to break inner nutrient packet. Confirm inner packet is broken. Shake the package well to release the nutrients. Allow package to incubate and swell for three hours or more at 70-75°F (21-24°C). Use sanitizing solution to sanitize the package before opening. Pitch into your wort or yeast starter that has been cooled to below 80° Signs of fermentation should be evident within 24 hours, depending on yeast strain, brewing procedures and fermentation temperatures.

Note: Do not panic if you pack does not swell. Sometimes the inner pouch can be difficult to break. Just cut off the top and pitch into your wort. It takes a lot to kill yeast, so try the pack anyway.99% of the time everything will turn out just fine.Note: Yeast can take 24 – 72 hours to show signs of fermentation.

• Give the yeast time to work before you start becoming concerned.
• If after 72 hours and no signs of fermentation, add dry yeast.
• If you are not sure if the yeast has worked or not; take a hydrometer reading, or taste the beer.
• If it is very sweet, the yeast has not worked.
• Dry yeast may start in a couple hours, but it can ferment a beer in less than 12 hours.

If you are not sure about the viability of your yeast then make a starter first. This will give you the opportunity to ensure that the yeast is working before you pitch it into your wort. Even if there are only two yeast cells left, that is all you need to ferment a beer.