Washing or Harvesting Beer Yeast

I’ve spent a fair amount of time online researching homebrewing tips and tricks ever since I started homebrewing about a year ago. One trick that I’ve been dying to try is harvesting yeast. Now, before I wrote a post about how to do this, I put my studies to the test over this past weekend and ended up with very happy yeast fermenting a raspberry oat wheat within 8 hours of pitching.

Many people harvest their beer yeast to save money. Okay sure, it’s a few dollars saved every time you brew… that’s nice. Others harvest yeast because the yeast strain is rare and they have plans to use it again in the near future. My reason is product availability. I don’t have a local homebrew supply store in Myrtle Beach. The closest store is over 2 hours away in North Carolina. I usually have to order supplies online and wait for the better part of a week to get my stuff, and who knows what temperature the yeast was exposed to during the shipping process. I once opened a box last summer only to find my yeast as if it were a hot water bottle – a little upsetting even though a cool pack was placed in with the yeast. I’d much rather just open my own fridge and grab some of my own. So that’s why I chose to harvest my own… now onto how to do it.

First thing to do is boil some mason jars: 1 large, 1500 mL jar and 3 small, pint sized jars. After all the jars and lids boil for 10 minutes or so, carefully remove them and let them cool. Fill them with the boiling water and let them cool for a few hours. Next, open each of them and pour the room-temperature water into the fermentor (in my case, a glass carboy). Swirl the carboy so you get all the yeast and trub off the bottom. You’re trying to get everything that’s caked to the bottom back into suspension. Once it’s all nicely mixed, lean the carboy on its side and let it rest for about 15 minutes. This will allow the heavier particles to sink. We don’t want any of this. The lighter stuff that’s still in suspension is your sleepy yeast that we want to save. Now that some of the junk is filtered out, go ahead and pour the milky liquid into the large ball jar, leaving the bottom sediment behind. Fill up the jar most of the way. Let that rest for another 15-20 minutes or so and you will once again see some of the heavier particles sink to the bottom. By this point, you can fill each of the pint jars with the cloudy liquid and seal them up. Put them in the fridge, and you’re done.

12-24 hours later, you should see a well-defined yeast cake at the bottom of the jar. This is what you would pitch into a yeast starter for your next batch of beer. I poured the top liquid off before I pitched mine into the starter.

From what I’ve read, other homebrewers have successfully pitched their own yeast up to 6 months after it was harvested from another batch. One thing I don’t understand is that a lot of people don’t think it’s worth the time to harvest original dry yeast. Most of the beers I have brewed in the past have been with Safale US-05 (dry) and from what I understand, it’s the same strand as Safale-1056, so why not harvest it? I followed the steps above and tried it for the first time this weekend with a yeast starter and had active fermentation within hours. I’ll probably harvest it again for a 3rd generation.

Have you ever tried washing your own yeast? Join in on the conversation with some tips or techniques if you have anything to share.

Boiling mason jars
Trub at the bottom of the primary fermentor
Rinsing yeast

4 thoughts on “Washing or Harvesting Beer Yeast

  1. Well I couldn’t have read this article at a better time. I am actually planning to harvest yeast for the first time from my Bell’s Two Hearted yeast culture. I pitched it into a big batch of IPA I made and I want to harvest the cake to be used in the future. For sure going to use some of the techniques from your article. Hopefully I capture enough Bell’s yeasties for many Two Hearted clones to come! Now off to the store for some mason jars.

    1. It was ridiculously easy Alex. Tipping the carboy on its side definitely makes all the differences to let the initial heavy particles settle out. Let me know how it works for you.

  2. Worked like a charm! I got three nice little yeast cakes in the fridge now. That step of laying down the fermenter, I think that was really helpful. Thanks!

    1. Nice! Glad it worked out for you Alex. I have to say that it’s nice having your own supply of yeast and the savings certainly add up.

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