Reusing Unwashed Yeast

Dave Greenbaum

Barley Legal Member
During the pandemic, I've made some changes to my brewing process. One is to modify recipes to use what I've got on-hand to minimize trips to the homebrew store. Part of this includes reusing yeast. In White and Zainasheff's "Yeast", it is advised not to reuse yeast without washing it. IOW, once a batch finishes fermentation and is siphoned out of the fermenter, don't rack a new batch directly onto the same yeast sitting at the bottom of the fermeter. I've been ignoring this advice and having tremendous results. Since being furloughed on Fridays, I've been brewing every other Friday. The first batch was a Jarrylo Pale Ale with US-05. I left it in the fermenter for two weeks and on that third Friday, I made a batch of Russian Imperial stout. After flame-out, I started the chiller and racked the Pale Ale into a keg. Once the RIS was chilled, I racked it into the same fermenter. On the fifth Friday, I did the same with an Irish Red Ale, and yesterday, the seventh Friday, followed with an Old Ale. The fermentations (except the first) have been monstrous. The only special precaution I've taken is to taste the prior batch for off-flavors, of which there have been none. Of course, I realize an infection could derail a plan like this, but having a huge population of yeast has worked wonderfully.
 

Frank Hiller Jr.

2018 Brewer of the Year / Interim Events Officer
I’d be interested in flavors you are getting from each batch.

ive read you can use the same yeast for similar style and to go to bigger beers. A big idea my pops does is makes a Scottish light and then we make a wee heavy we pitch on that cake. Same style, bigger beer.
I’d be interested in if anything from the stout affects the irish red...or now the old ale.
Very intriguing Experiment
 

Dan_Ell_Wang_Er

Barley Legal Member
One suggestion for anyone else trying this is to keep as much hop material out of the primary fermentation as you can. You could use hop bag/spider etc, but the extra hop material building up can have an effect of future batches if you're not restricting the hop debris.
I did this one summer a couple years ago when I was brewing more consistently. I brewed 5 beers and cider with 1 satchel of Nottingham yeast. That yeast is already a monster, but batch after batch it went crazy. Think I had a bucket lid blow off too.
Now when I'm doing this, I usually scoop some of the yeast cake out of the bottom before transferring on top, unless I'm aiming for a big brew.
 

Mtorbik

Barley Legal Member
Late to the party on this one... But I have conicals so when I harvest, use a hose to a mason jar. Dump the first bit and then save the rest that comes out. I almost always take from that and do a starter for the next batch. So thats the extent of "washing" it gets. I've used yeast off dark beers into light... And vice versa.

Recently I needed S-05 and couldn't get it in as fast as I needed it. Had a buddy with a beer in the fermenter with coffee and cinnamon in it. Pulled some s-05 from that... Did a small starter and let the cinnamon and coffee chunks settle out.... And then did a 2 Liter starter for a sour. No cinnamon or coffee came through at all
 
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