How to reuse beer yeast?

In this brief article, we will answer the question, “How to reuse beer yeast?” and the steps and tips to harvest yeast for reusing it.

How to reuse beer yeast?

You can reuse beer yeast through a technique known as yeast harvesting. In yeast harvesting, the yeast left in the beer is reused multiple times which can be cost-effective and useful too.

How to harvest yeast?

It is easy to harvest yeast. You need not be an expert brewer to perform the harvesting. Just follow these simple steps.

  • Start sterilizing the water in the first step. You can use 1 liter of water for this purpose. Boil the water for 10-15 minutes. After the water boils, switch off the stove and allow the water to cool at room temperature.
  • After the water cools, place them in a fridge. Do not place the hot water directly in the fridge. Allow it to cool at room temperature before placing it in the fridge.
  • In a sanitizer solution, place three mason jars. Sanitize them well. At least one jar should be able to occupy the slurry present in the fermenter along with large quantities of water (4 times water).

If you do not have a sanitizer solution, you can sterilize the jars in clean boiling water.

  • Clean the carboy’s rim by sanitizing them. These steps would prevent the yeast from being infected.
  • Shake the fermenter containing the yeast sediment to break the layer of trub. If you are unable to break the trub easily, use sterile water. You can also add a bit of yeast along with sterile water and try breaking the trub again by shaking them.
  • After you have swirled or shook the fermenter, transfer the liquid to the mason jar. Seal the mouth of the jar by covering it with a lid.
  • The trub should remain in the bottom after separating from the yeast. The trub would have a dark brown color while the yeast would be of a lighter color. Filtering out your hops is important to achieve this separation.
  • Look at how much trub is present in the jar. If you have very little trub then it is fine. If the trub is present in the bottom of the jar, scoop out the white layer present above as that is the yeast.
  • It is essential to separate the yeast from the trub. If you find a lot of trub in the jar, separate the white portion (yeast) into another jar and the liquid to another jar. Shake the jar and wait for 25-30 minutes. 

You can keep repeating this process to obtain a healthier yeast without the trub.

  • After you have completed this process, close the lid of the jar and place it in the fridge. You would find that the yeast has settled to the bottom of the jar.
  • To reuse the yeast, take out the jar and pour the contents of the jar onto another jar. Be careful to remove only the top portion above the yeast and leave the yeast behind.
  • Shake the yeast and use it as a starter or as a fresh pack.

How many times can beer yeast be reused?

You can use the yeast for 5-6 generations. Some individuals also use till ten. It is usually a matter of what one prefers. It is important to note that with each generation, more bacteria get introduced to the yeast. 

Can plain water be used to sanitize instead of boiling water?

No, plain water is not as effective for sanitizing as boiling water. Boiling water also lacks oxygen because it is effective in sterilizing and this would help in preventing the yeast from getting infected too.

What tips need to be kept in mind before harvesting yeast?

  • Before using the yeast for harvesting, it is imperative to check for the color of the yeast as well as the smell of the yeast. There should be no unpleasant smell coming from the yeast.
  • The yeast you plan to use should have a thicker and creamier texture. It should also not contain excessive amounts of trub too.
  • If the beer was highly hopped, then you might not be able to reuse the yeast more than once.
  • Look at the alcohol content of the beer also before reusing the yeast. If the alcohol content is more than 6.5% in the beer, then avoid reusing the yeast.
  • Try on finishing the reused yeast within a month and make sure to keep it in the fridge. If the taste gives off a weird odor, discard it.

Other FAQs on beer that you might be interested in.

Other FAQs about Yeast that you may be interested in.

What is the economic importance of fermentation by yeast?

What does yeast come from?

What is the difference between pizza yeast and regular yeast?

What are the products of fermentation in yeast?


In this brief article, we have answered the question, “How to reuse beer yeast?” and the steps and tips to harvest yeast for reusing it.