Money Saving Tips – Repitching YeastWednesday, November 26th, 2008
Update 11/12/2011: Check out the article on Bad Batches to see why you might want to avoid re-pitching yeast, or if you do so, make sure to understand the risks involved.
Did you know you can save ~10% on your next batch of home brew by re-pitching yeast? Some brewers buy new yeast for each batch. That is a good way to guarantee results provided the yeast is within the expiration date and has been refrigerated properly. However, at $7 a hit that comprises about 20% of the cost of the batch! With a little planning in terms of recipes and beer styles you can easily cut this in half or a third. It is a normal thing to do. The commercial breweries reduce their costs by repitching over and over.
Harvesting the yeast cake at the bottom of a finished primary fermentation vessel is easy. After siphoning off the beer into the secondary or bottling bucket the yeast will be left behind. Pour the yeast slurry (also called the yeast cake) into a sanitized container for safe keeping. You may need to loosen it up with some clean water. The yeast can be saved for several weeks in the fridge. It can be siphoned into regular 12oz bottles and capped, or put in a jar with an airlock.
The yeast can also be repitched immediately if you rack or bottle your old batch while you are cooling your new batch.
Do not repitch yeast that came from a contaminated batch, or had a weak or incomplete fermentation. Any yeast that had a healthy fermentation will work for this technique and it can be repeated many times. The maximum I have heard is ten times. That is getting up there and would limit choices of beer styles. Yeast can be a big factor in flavor and body. See a complete list of yeast strains by clicking here.