Yeast Washing

I prefer to use liquid yeast in all my brews. While dry yeast will give you enough viable yeast in a dry packet, it doesn't have the consistency from batch to batch that liquid yeast does. However there is a price difference between liquid yeast (~$7) and dry yeast (~$1). In order to start saving a bit of cash, I've decided to start washing my yeast.

Yeast washing is a process by which the yeast is seperated from the trub. The trub is a mixture of hop remnants, dead yeast cells, and other unwanted particulate. By seperating out the trub from the yeast, we are able to reuse our yeast for future batches.

Step 1

Boiling the Jars/Water

Full Sanitized Jars

Seperating Trub in Carboy

The process for washing yeast is quite simple. The first step is to sanitize a few large (I use half gallon) mason jars, as well as 2 or 3 pint jars. I used our boil pot as well as some reverse osmosis water. I boiled the jars and lids for approximately 20minutes. After the boil, I promptly covered the jars with the lids, and set them aside for a day to cool. The nice part about this step is it can be done anytime before the racking in the next step.

Step 2

After racking the beer out of the secondary, I pour the water from all the mason jars into the carboy. The carboy is then shaken in order to agitate the sediment off the bottom. I then lay the carboy on its side. In 20 to 30 minutes trub will have fallen to the bottom of the carboy's side. It is at this point that the carboy is slowly poured into the larger mason jar. The goal of the pouring is to leave most (if not all) of the trub behind in the carboy. Note that the basic premise to this is that trub is heavier then yeast, therefore the trub will fall to the bottom, while the yeast is still suspended. After filling the larger mason jar, I put the jar into the fridge to accelerate the yeast dropping to the bottom. I try to keep the jar refrigerated for at least 48 hours, but for this batch I kept it in there for about a week.

Step 3

After most of the yeast has settled to the bottom of the gallon jar, you should be able to see 3 different layers. The top liquid layer is the mixture of beer and water. The second layer is the yeast, and the bottom layer is the little bit of trub that made it in from the carboy. You can see to the left the before and after pictures of the gallon jars. When the water/beer mixture starts to become translucent, it is time to transfer over to the space saving pint mason jars.

Step 4

Seperating Trub in Gallon Jars

Filled Pint Jars

In order to save space in the fridge, I have to consolidate yeast. This step involves decanting off the water/beer mixture from the gallon mason jars, and then transferring them to the smaller mason jars. This is essentially the same as step two just done on a smaller scale.

The yeast will eventually settle to the bottom of the pint jars in the same way it settled to the gallon jar. This yeast then can be stored for a period of months to be used in another brew. However, reused yeast should likely not be pitched as it is. It is best to create a nice sized starter to make sure you have enough viable yeast. The Mr Malty website has a nice calculator for determining how large of a starter you'll need based on your beer.