How to stop fermentation in beer (+ home brewing tips)

In this brief article, we will answer the query, “How to stop fermentation in beer?”, discuss each method and give you some tips for homebrewing.

How to stop fermentation in beer?

Beer fermentation can be stopped by refrigerating, filtering out the yeast, pasteurizing it, or adding Potassium sorbate. Choosing the method depends on why you want to stop the fermentation and all the circumstances involved in the situation.

Usually, beer fermentation stops naturally, without any interventions. However, there are some cases when you need to stop it sooner. 

First, you need to know what beer carbonation is. Carbonation preserves the quality of the beer and provides a specific amount of carbon dioxide (CO2) in the beer. Part of this gas is already formed in fermentation since the yeasts metabolize the sugars.

Chilling the beer

This is the most simple method for stopping fermentation, however, it can not be used for all reasons in circumstances. 

In refrigerator temperatures, the yeast slows its activity and can not operate converting sugar into alcohol.

Filtering the yeast

In some cases chilling the beer is not an option, so another simple method is by filtering the yeast.  

This technique can eliminate the yeast, stopping the fermentation. This process, though, has to be with a sterile filter with at least 5-micron pores, which will ensure that the yeast is completely filtered and the fermentation will actually stop. 

It is important to keep in mind that this method could also reduce the flavor and aroma of your beer.

Beer has always contained some yeast, so it is an expected component of the flavor profile. The yeast filtering process can be more or less noticeable depending on the style of the beer.

Thus, this filtering method is simple but should be avoided.

Adding potassium sorbate

This method does not interrupt fermentation, but it can prevent yeast from reproducing. Thus, this method avoids the acceleration of the fermentation process. 

Adding potassium sorbate may be the most suitable option for the cases when the fermentation has already achieved the target level, so you just want to avoid that the fermentation restarts. 

For using this technique, you may add 5 teaspoons of potassium sorbate mixed into 25 cups of boiling water to each gallon of beer. 

The use of boiling water ensures that it is sterile and completely dissolved in the liquid. 

Pasteurizing the beer

Pasteurization is a sterilization process for foods and beverages which consists of exposing them to a temperature below their boiling point in order to eliminate microorganisms, like yeast.

The beer fermentation stops by this method because the yeast will be dead. 

The ideal temperature to guarantee that the yeasts are dead is around 140 °F (60 °C) for several minutes. The bottles can be submerged in a recipient of hot water until the temperature is reached, then leave them there for several minutes.

Besides the extra effort required, another disadvantage of this method is that the heating process may alter the flavor of the beer. 

Tips for homebrewing

  1. Begin with darker beers.

The best place to begin is with the dark beer since they are typically better at masking possible mistakes that you may have committed. 

  1. Pay attention to the water that you use

It is critical that the water used to make beer at home be chlorine-free. Any amount of chlorine in the water will produce the dreaded off-flavor chlorophenol. 

To avoid the presence of chlorine in water, you should buy water in gallon containers or filter the water with a three-stage filter with one activated carbon filter element to remove chlorine. 

  1. Make notes

Write down all the steps you took, including ingredients, temperatures, and times. This is critical if you want to replicate this recipe and improve the steps you need or replicate a successful recipe. 

  1. Temperature control during fermentation

Brewing yeasts are extremely temperature-sensitive. Each style of beer has its ideal yeast, hence, it has its ideal temperature. A temperature controller is required for yeasts to work in their optimal fermentation range. 

Other FAQs about Beer  that you may be interested in.

Does beer go bad if it gets warm?

Does beer have acid?

Does beer cause constipation?


In this brief article, we answered the query, “How to stop fermentation in beer?”, discussed each method, and gave you some tips for homebrewing.


“How To Stop Fermentation in Beer (4 Different Methods) – Learning to Homebrew.” Accessed December 15, 2021. “Home Brewing Tips: 6 Things New Brewers Should Know,” July 18, 2013.