Home » Tips Register | Login
« Back to Tips page summary

Tips: Ingredients: Yeast

« Previous TipNext Tip »

Yeast Harvesting/Washing

Submitted by: Special thanks to Alan McKay (Bodensatz) and Denny Conn on November 20th, 2003

There isn’t anything magical about my technique for harvesting yeast… since I don’t think I’ve ever really documented it I thought I’d do so now and post it….

I would describe my technique as a combo of what is on the WyEast site and what Alan describes on Bodensatz (or at least used to – haven’t seen it in a while).



It’s really simple, just long winded to explain…

Reminder: SANITATION SANITATION SANITATION is essential for success.

Prep work:

In large stock pot, put in several quart and/or pint mason (canning) jars. If you put enough in there they won’t rattle around and possibly chip each other.

Put lids/rings in hop bag and place into pot along with the jars. Include a couple extra, just in case. By the way – make sure these are the RIGHT lids for the jars (oops).

Fill jars and pot with water to about 2-3 inches above tops of jars.

Cover with lid.

Bring to boil and let boil for 20-30 minutes.

When done boiling, either let stand or better yet, cool in ice bath in sink until jars are safe to handle using tongs (or whatever).

Remove jars and rings from pot. Leave jars full of water.

Seal with lids and put in fridge to cool for at least several hours.

Note: If you happen to have something that you can store off the remaining water from the pot, this could come in handy. Sanitize and fill, then store this along with the filled jars in the fridge.

This prep work accomplishes several things: Sanitizes jars/lids; sanitizes water; removes O2 from water that the yeast will be in; creates a cool medium for the washing process which makes stratification easier than if using warm water (I know).


Siphon beer out of fermenter.

Pour water from each of the cooled jars into the fermenter. Put lids back on jars to remain sanitized. If you happen to have saved off the extra water and chilled it, add an extra quart or two of this water to the fermenter.

Swirl (not splash) until everything in the carboy is in suspension.

Pour into one large sanitized container – perhaps the one that you had stored the extra water in. I use one of those gallon sized mayo jars like a restaurant uses.

Cover this large jar with cling wrap.

Let stand for anywhere from 15-45 minutes. Thickness of the trub and temp of the water effect how quickly the contents of the jar will stratify.

When you see what looks like a well formed layer on the bottom, that is the crud containing proteins, hops, bee’s knee’s, whatever that’s settled out.

What remains in suspension is the goodies. Start filling your mason jars with this suspended liquid trying not to disturb the layer on the bottom of the big jar too much. But if you do – don’t sweat it.

Label jars with yeast strain and date.

Bingo – you’re done…

There is a trick to this technique that I’ve learned to use… If you are like me and normally make a large starter, you don’t necessarily need a really huge jar slurry for pitching. What I do is when I am filling my mason jars I start filling the big ones first, since the liquid in the Big Jar is ‘thinnest’ at the top and gets ‘thicker’ with yeast as you pour. So you need a bigger sample at the beginning to get the same amount of yeast as you work your way down – get it?

Other than the boiling time for the water, this whole process works out to take about 30 minutes, though I’ve done it in less.

When I do this process for a friend this weekend I’ll try and take pictures. I’ve also got a pale ale I need to keg for a party at Rob’s so I’ll try and remember to snag a few photos of that as well. What would be good to show is the stratification and volumes of yeast in the jars, since this concept threw me when I first started harvesting yeast.

This (and similar) techniques give you enough yeast slurries that you can almost consider yeast as a ‘free’ resource in your brewing costs. Between harvesting and repitching I’ve done 11 batches using the same initial yeast purchase (about 65 cents a batch). I could have just kept going for a long, long time but fell in love with a different yeast and started using it instead.

Think about it: you buy a tube of your favorite yeast, make a starter and brew with it. You harvest 4-6 slurries from the primary… from there you use one to brew again, harvest the slurry, now you have 4-6 more samples as Generation #2… and so on, and so on….

Done properly, yeast harvested like this can be stored for quite a while in the fridge. Don’t let it freeze or you’ll kill the yeast. My last three batches were made using a slurry I harvested back in May (I made a starter of course).


5 Comments Posted
add new comment ]

Re: Yeast Harvesting/Washing Nov 24th 2003, 03:50 am
The only caveat that I would apply would be to only re-use your yeast up to the 4th generation. After that, you could be looking at too much mutation. That being said, if you collect 4 samples from each generation then you have enough yeast for 256 batches.
Comment by: ModlrMike reply to comment
Re: Yeast Harvesting/Washing Nov 27th 2003, 05:46 am
I think washing your harvested yeast is a waste of time! Just save the yeast on the bottom of the carboy in a clean sanitized mason jar. Repitch within a week and if not make a 1 litre starter to get the yeast going and pitch as normal.
Comment by: borny reply to comment
Re: Yeast Harvesting/Washing May 6th 2004, 08:43 pm
My thoughts would be that after several generations you may get mutations but would it not be more of a strain purification to your particular brewstyle especially iof you do a loop back withthe batcheset-al mix gen 3 with 1, 6th with 2 to develop your strain.this would be like selective inbreeding of animals to get to a new breed.
Comment by: robotralph reply to comment
Re: Yeast Harvesting/Washing Feb 3rd 2004, 02:22 am
I have a couple questions on the procedure. First, do you fill the jars to the top so there is no air or is that not a concern? Second, is there any reason you can not use beer bottles and just cap them? I want to try this this weekend so any comments would be very helpful.
Comment by: Randy reply to comment
Re: Yeast Harvesting/Washing Apr 12th 2006, 04:20 pm
first question, how do you seal the jar? if you use the mason jar lid, any change of it exploding?

second question, I wanted to havest yeast from sediment of a store bought beer. should I use the sediment to do a starter then pitch? Any tricks to doing that?


Comment by: Mike reply to comment