How Many Times Can You Reuse Yeast? Here Is My Experience

By Simon in Beer Brewing

While being a homebrewer materials can go to waste, what a shame. However, some materials can actually be reused, such as yeast. But be aware, there are some certain precautions to deal with.

How Many Times Can You Reuse Yeast? There are different ways to reuse yeast on, but one rule of thumb is to only reuse your yeast five or six times. You may be able to use it more than that, but that’s a risk you shouldn’t take.

Are you a beer brewer and would you like to reuse your yeast, but need more knowledge before action? Do not despair. This post will take you through reusing of yeast, how to clean it, how to store it, and much more.

How To Reuse Yeast? And How To Clean It?

It’s a shame to throw out yeast after every use, and what a waste when you can reuse it. Not only you can save a lot of money, but you can also jump start the next batch with a much larger pitching volume.

Overall, there are two methods to collect yeast for reuse. It all depends on if you are collecting from the secondary or the primary fermentor. By giving a variation between simpleness and predictability, each method has its benefits.

Secondary Collection

It’s much easier to reuse the yeast in the secondary than opening up a new pack of yeast. In this collection, there are fewer trubs than in the primary collection. Thereby you can rack the fresh wort on the top of the yeast cake and already have a fermentation almost immediately.

Do you prefer to start the new batch in a clean carboy? Just pour the slurry into the fresh carboy. But always remember to sanitize the neck and lip of your secondary with a spritz of sanitizer.

Please note that you don’t necessarily need to oxidate the yeast cells. Normally yeast cells need oxygen during the production phase, but in this concentration, they won’t really need to reproduce much.

The easiest method to reduce the yeast here is to immediately pour it into the next batch. But of course, you can also store it for later use.

Primary Collection

The yeast will be more fresh in this stage because it will be closer to its original culture than if you are reusing the yeast from the primary.

But always be aware of this method. It will take a little more effort from you, in terms of separating the viable yeast from the trub.

This process is originally called decanting, but some might just call it washing or rinsing of the yeast.

After you have diluted the mix from yeast and trub, you will have to pour liquid and yeast off the heavier trub. It’s possible for you to choose more decanting steps to reduce the amount of trub further, but this is not necessary.

I will now guide you through with a guide on how to reuse the yeast from the primary collection:

#1 Start sanitizing several glasses or containers.

For this, you will need a large one for the decanting, but also you will need some jars to hold the final collection. Are you going to pour it all in the next batch, you need one more large container.

To dilute the yeast and the trub mixture, you have to boil 2-4 quarts of water, and then cool it down, to sterilize it.

#2 Pour sterilized water into the primary just after you have poured the last beer into the secondary.

Now, to mix the liquid and the sediment, swirl the carboy. After, let the carboy settle for around 30 minutes before moving to the next step.

#3 Thoroughly clean the neck of the primary, and pour the yeast layer and the liquid layer into the firs large container.

You should now be able to see three layers; a layer of liquid, a layer of beige yeast, and a dark layer of trub.

REMEMBER: Be careful here, and leave as much of the dark liquid layer of trub as possible.

Seal the container, either with a sanitized lid or some plastic wrap. Swirl the mixture again and let it settle for around 45-60 minutes.

#4 Repeat step #3

You should be able to see the same three layers of liquid as before, just a bit thinner this time. Now do the same again, by pouring off the liquid and yeast layer, and leave the trub. This time you’re decanting into the storage container. Seal and refrigerate these for later use.

How Do You Store Yeast After Brewing?

You can collect it all in a container or jar, or you can split it up in multiple smaller containers. The yeast should always be stored in the fridge. When you are ready to use the yeast after storing it, always remember to bring your yeast to pitching temperature before use.

REMEMBER: The yeast should not be stored more than 4-6 weeks, even though it might be able to last longer than that.

You should be able to tell when to stop using the yeast. When it starts to have a brown color, the yeast has pretty much died. If the yeast is only a little bit brown, you should be good to go, but if it’s getting darker and browner, do not use it anymore.

What Should You Watch Out For While Reusing Yeast?

As mentioned above, the color is important to pay attention to. Furthermore, you should also pay attention to the smell of the yeast.

Your yeast should look thick and creamy.
Also, it should not have any so-called ‘’off’’ flavor and aromas
It should contain as little trub as possible.
If the yeast smells off sulfur or phenolic, don’t use it, it might have suffered from sanitation issues or some other type of stress.

Bottom line – If you are in any doubt whether your yeast is able to be reused, don’t reuse it. It would be such a shame if you had to throw a whole batch of beer away because you took the chance.

Do you need more information about homebrewing? Check out this post: Is Homemade Beer Dangerous?

Can I Put Too Much Yeast In My Beer?

This is actually an exiting question and a bit cringed. There is a possibility for both over-pitching and under-pitching.

Homebrew that just reeks aromas of cider, alcohol, or solvents of fruit is often caused by under-pitching (by not adding enough yeast).

When not enough yeast is used, the yeast has to work harder to eat the sugar, reproducing, and creates nasty aromas and flavors.

Over-pitching, on the other hand, results in less taste of yeast. That means; adding less yeast produces more yeast flavor and adding more yeast produces less yeast flavor. If that even makes sense?

Also read: Do You Need Sugar To Brew Beer?

What Can Be Reused In Brewing?

While talking about reusing in brewing, it’s basically only the yeast you can actually reuse. But it’s possible for some ingredients to be stored as well.

Fresh ingredients are obviously better, but old ingredients can actually be used for brewing as well. If they are only stored properly, the old ingredients can remain their freshness.

Mainly there are two ingredients there can be used as ‘old’; grain and hops.

Grain

Grain doesn’t have a ‘best before’ date. But of course, the older it gets, the less flavor it contains, which ends out in a boring beer or even nasty flavors. The signs of age are damp, no crunchiness, flavorless or moldy.

Normally the ‘fresh’ grain will last around 20 days or so. But if the grain is stored properly, it can last up to 12 or even 18 months.

You will not have to vacuum seal the grain, although this will make it last even longer.

TIP: Store whole grains cold and dry, to make it last that long

Hops

If the hops are vacuum sealed and stored in the freezer, it can last up to 2 years. But always remember that the hops only are harvested once a year. Therefore you should buy them in the fall, where they will be freshest.

The most substantial signs of aging hops are is they lose their smell, or even gets a cheesy or moldy smell.

The consequence of adding too old hops to the beer is, that the ability for hops to bitter your beer decreases with time.

Are you even more curious about home brewing, try out this post: How Long Can I Leave My Beer In The Fermenter?