Can you Stir the beer during fermentation?

Homebrewing can be a tough subject to get started with, and learning about fermentation and all its intricacies is something you need to master if you want to be able to produce high quality beer at home.

In this article, I will be going over if you can stir the beer while it’s fermenting, if you need to stir it once you pitch the yeast, how the fermentation process is supposed to go, and more.

So, without any further ado, let’s get started!

Can you Stir the beer during fermentation?

Stirring beer while it’s fermenting is not recommended since it can introduce harmful bacteria as well as oxygen into it, resulting in off-flavors and unwanted aromas, as well as a shorter shelf life. A better solution is to shake the fermentor a little, since this is more than enough to reactivate the yeast.

There really are no reasons to stir the beer while it’s fermenting since this could only cause issues. If you have a stuck fermentation, the better solution would be to shake the fermentor, but never open it up and stir.

How is the fermentation process supposed to go?

Once the wort has cooled down and you pitched the yeast, all that’s left to do is close the fermentor (with an airlock or blowoff tube on top) and let the yeast do it’s thing. If everything went according to plan, then you should see a nice thick foam appear on top of the beer, which is known as Krausen and is part of the fermentation process, which lets you know that fermentation is taking place.

All that is left to do now is wait until fermentation has subsided and it’s time to move the beer to a secondary fermentor (unless you’re fermenting your beer under pressure, in which case there’s no need for a secondary fermentor).

Is there a reason to stir your homebrew during fermentation?

Stirring fermenting beer, even if the fermentation is stuck, is never a good idea because it can introduce bacteria as well as oxygen and it should always be avoided. A better alternative would be to shake the fermentor since this can help reactivate the yeast.

There may be numerous reasons responsible for your fermentation not being able to start, such as; The yeast being too old, yeast getting pitched into a wort that is too hot or too cold for that particular yeast strain, lack of oxygen in the initial wort (yeast need oxygen to get the fermentation going), and overall, not pitching the right amount of yeast.

Does stirring stop fermentation?

Stirring the beer while it’s fermenting won’t cause the fermentation process to stop, but it may introduce bacteria and oxygen which could result in off-flavors and unwanted aromas.

In short; Don’t open the fermentor and don’t ever stir the beer.

When pitching the yeast, does it need to be stirred in?

At the moment of pitching the yeast, stirring it in doesn’t add any real benefit, but it can cause a couple of problems, such as the yeast getting stuck to the side of the fermentor preventing it from being used as part of the fermentation, and it increases the risk of beer infection because there’s a higher chance of introducing bacteria.

The only benefit I can think of is that stirring in the yeast may introduce a little more oxygen into the wort, which helps with getting the fermentation started. But other than that, there are a lot more negatives than positives and the fermentation will work regardless.

One recommendation I would give you is to aerate the wort before pitching the yeast. You can do this by either agitating or shaking the fermentor, or by using a whisk. Just make 100% sure to sanitize the whisk before touching the wort with it.

Stuck fermentation? Here’s what to do!

The first thing you need to do is to check if your fermentation is actually stuck, since even though there’s no Krausen, or maybe it has dropped very quickly, this doesn’t mean that fermentation is still not ongoing.

To tell if the fermentation is actually stuck, you first need to have measured the initial gravity of the wort (this is something you always need to do), and then you need to take two separate samples 48hs apart to see if fermentation has stopped or not (you could also take a sample a day for three days).

If the gravity doesn’t change between those two samples, then that means that fermentation has subsided.

If the gravity is still too high but the beer has stopped fermenting, it means that you got a stuck fermentation. If the gravity reached the levels it was supposed to, then it means that primary fermentation is complete.

Here’s what to do when you got a stuck fermentation:

  1. Heat up the Fermentor: A significant drop in temperature can cause the yeast to go dormant and settle to the bottom. Moving the fermentor to a warmer room, using a brew belt, or any other way of heating up the brew, will solve this problem.
  2. Shake the Fermentor: Shaking or swirling the fermentor will stir up the yeast and bring it back into suspension, generally solving the problem.
  3. Add more and better Yeast: Weak yeast or low volumes of healthy yeast will often not be able to ferment a high gravity wort (most common with higher gravity beers).

Can you shake the beer during fermentation?

Softly shaking the fermentor can help reactivate the yeast if the fermentation process is stuck, but other than that, you should avoid shaking the fermentor since this will introduce oxygen, shortening the beer’s shelf life.

Can you move beer during fermentation?

Moving the beer to a warmer or cooler location to achieve a more ideal fermentation temperature is definitely something you can do, just try not to shake it too hard as not to introduce too much oxygen in the process.

Should you stir the beer before bottling?

Stirring beer before bottling is not recommended since all the yeast and protein sediment will be stirred back into the beer and make its way into the bottle. The beer will also come into contact with oxygen causing oxidation, making its shelf life shorter.

We generally use a cold crash to force all the yeast, proteins, etc., to drop to the bottom of the fermentor, which would essentially be the sediment I was just talking about. Stirring that back up after we purposely made it drop doesn’t make a whole lot of sense.

What I mentioned about oxygenation is not as big of a problem because when bottling the beer we add sugar, which means that there will be some fermentation going on inside the bottle that will consume the oxygen.

Still, it’s best not to let the beer come in contact with oxygen as much as possible.


Stirring brew while it’s fermenting isn’t a good idea since this might introduce bacteria and oxygen, which might cause the brew to not only have a reduced shelf life, but also to have to be thrown away.

If you’re suffering from a stuck fermentation then you should consider shaking the fermentor a little, or increasing its temperature to the range needed by the yeast you’re using so that the fermentation process can go on unhindered.

I hope this information was useful!

Have a nice day!

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