How to Re-Use Yeast to Make Beer

Several batches of beer can be brewed from the same yeast.

Re-using yeast in the beer brewing process is not just a step towards greener living, but also an effective way of saving money without sacrificing beer quality. Ron Page, brewmaster of City Steam Brewery in Hartford, Connecticut, considers it a necessity, as it keeps costs down and makes it possible to keep prices within reason. The task requires a brewer with a seasoned palate, to ensure that the yeast is discarded before it is overused.

Things You'll Need

• Active fermenter
• 3 qt.-sized jars, sterilized and half-full of sterile water
• Cold storage

Instructions

1. Remove ale yeast during the primary fermentation and lager yeast during the secondary. After siphoning or pouring off the current brew, add a small amount of sterilized water to the carboy and gently swirl to lift the dregs. Pour a cup to a pint of this liquid into one of the sterilized jars.

2. Gently agitate until the ingredients are visibly separated. Pour the top layer of yeast off into a second jar and agitate a second time. Allow the contents of the jar to settle for about half an hour, long enough that the layers seem pure and have not begun to remix. Pour off the top layer of water and bits of hops and discard, then pour the second layer of suspended yeast into the third jar.

3. Store the third jar in a refrigerator, as close to 32 degrees as possible. For the first few days, open the jar once or twice a day to release gases produced by the yeast until it enters dormancy. Allow the yeast to come to room temperature gradually prior to repitching it. Use washed yeast within two weeks to a month.

Tips & Warnings

• Page recommends using an ale yeast between six and twelve times and lager yeast only three to five times. Monitor the flavor of the brews for any drop-off in taste quality, indicating the yeast should be discarded.

• Sanitize everything that comes into contact with the yeast thoroughly.

References

• Home Brew Digest: Yeast Information and Technique Resource
• Brew Your Own: Harvesting Yeast Techniques