Yeast Harvesting: A Novel Approach?

[lstrowge]

I'll add my thanks for posting the original method as well. I've been "attempting" the yeast washing from feremented batches for about a year now and have had mixed resluts. Your's definitely looks to be a better method than I have been doing. One thing that may help with the issue of superheating jars, I have been boiling a quart jar and 4 to 6 jelly jars in water and then capping them full. I recently have had left over jelly jars that I set aside and use that now sterile water to mix for my second washing. I intend to pre-boil/package sterile water/jars for use with your method. Avoiding the microwave altogether. I just have to dip the jar in star san (closed ofcourse) before i uncap and pour.

 

[Brulosopher]

@lstrowge That's a great way to sterilize both water and jar, in fact I've done it before as well. I simply like the the ease of using the microwave. Cheers!

 

[Weezy]

First off, this is *awesome*...thank you! I think I might go about it like UofMontanaAlum suggested about just splitting the first starter up into several jars for refrigeration, rather than pitching any of that original starter. Make new starters from those jars for use. Let's call it an initial harvest.
Secondly,
I'd like to recommend a slight clarification to Step 6 (recommended additions in CAPS):
"Step 6: The next day, decant about 80% of the beer off of the pre-harvested yeast in the larger mason jar, WITHOUT DISTURBING THE YEAST ON THE BOTTOM. LEAVE 20% OF THE BEER TO HELP agitate AND release the yeast from the bottom of the jar. Then simply pour the yeast directly into the previously boiled water in the smaller mason jar."

 

[Brulosopher]

@Weezy Thanks, I appreciate the clarification. Now if I only I had the ability to edit the original article

 

[sethlovex]

Great article bru. I was searching for this info a few days ago, why isn't this article stickied?

 

[Brulosopher]

@sethlovex A few people have suggested it be stickied; I think TxBrew is the person to contact for that

 

[fall-line]

Good post, this is pretty much exactly like what I've been doing since having similarly suspect results with washing. Since my stir plate and flask are capable of growing very large colonies of yeast (much larger than a 5 gallon batch requires), it's easy to just make a little extra for later.
I haven't been transferring to the smaller jar with boiled/cooled water though, I'll give that a try.

 

[Accidic]

Maybe I'm just being really dense here but I'm not really clear on why this is so much easier than "Washing" (read: rinsing) the yeast to begin with. For all intents and purposes it's still seems like the same process, just nailing it from the starter (and likely hopless) rather than the Primary. I'm not knocking it, I've done the same process previously and just used it as a base for a starter when I had two batches that were going to be down near simultaneously but brewed at different times.

 

[Brulosopher]

@ fall-line: The sterilized/de-O2 water part is done only to provide a more hospitable environment for longer term storage. If you use the harvested yeast within 2-4 weeks, I'm not even sure that part is necessary.
@ Accidic: Not dense at all! It's not really the same process because there is not yeast washing (really "rinsing") part to this method. You simply pour .5 liter of wort off of a starter and save it for later. This takes me a whopping 3 minutes. Harvesting and rinsing (multiple times) yeast that has already been used in a beer usually took me at least an hour, as I had to wait for the yeast to stratify, blah, blah. Plus I always ended up with 4 jars, which I'd usually end up tossing 3 of. And yes, I absolutely prefer the fact the yeast I collect using the starter method is hop free, the only junk I collect is a little protein break material from the DME, which is no biggie. Hopefully that clears some things up. Cheers!

 

[Jbear]

Brulosopher - good write up! I've been utilizing pretty this exact practice for the last year or so with outstanding results as well. I don't usually store longer than a couple months, so I actually don't decant my saved culture from under the starter beer and have not had any problems.
Regarding estimating your cell count in the saved slurry that some people have asked about. Here is how I do it: Using the OP's example of 2.5L starter with .5L saved, 20% is kept. So if mrmalty/yeastcalc says my 2.5L has, for example, 220 billion cells, I estimate that I have kept 44 billion and use that + the date for the next batch. Given that is ~1/2 of a smack pack, stepped starters really become your friend.
@Accidic - it seems a lot easier than washing/rinsing to me because there's very little trub to get rid of in 500mL of starter wort, so I don't bother with it. Also, when making a starter I'm already in the kitchen with the stove on so getting a jar ready is easy while waiting around for my starter to boil. With washing I found myself either waiting to rack beers, or racking and just tossing the yeast anyhow because I didn't have various sizes of jars sterilized.

 

[Brulosopher]

@ Jbear - I was thinking similarly regarding the cell count thing, I just didn't want to make the erroneous assumption my thinking was right . It makes a lot of sense to me, theoretically; however, what doesn't make sense is that I end up with more yeast slurry in my jar than I've ever seen in a WL vial, which seems to contradict the idea there are only 40 million good cells in there. Also, I've never stepped up a starter using this method, even on 1.065+ beers, and they all get going within 12 hours and turn out fantastic. I'm admittedly confused... in a good way!

 

[ViperMan]

Question - when you make a starter with an extra .5 liter, do you add 25% more DME?
I'm going to try this out 'cause I'm tired of buying yeast vials all the time...

 

[Jbear]

I don't have a microscope, so all I really have to base my assumptions is doing the math. I do agree with you that my saved batches appear to be at least the size of a vial, if not more. I have always figured it is mainly trub, since we aren't washing/rinsing the sample. Its pretty clean trub, however, being an unhopped all DME wort only boiled for ~5 minutes so I think it blends with the yeast better. This explanation is my personal experience, but unless all the yeast calculators out there are off by 100s of billions - I just don't see how we can have more cells than that.
In practice, I have not done many stepped starters either, because I rarely start it far enough ahead of brew day for the extra chill/decant days. However, I'm brewing more 10 gallon batches these days I am starting to force myself to plan better. As an example starting with 97b cells (the yeastcalc.com default) you can hit 507b cells with a 5L starter. Or you can hit 506b with 2 1.4L starters. (all are stir plate numbers) Over time that 220grams of DME saved will add up!

 

[Brulosopher]

@ViperMan - Not necessarily 25%, as the amount of DME I use ultimately depends on the volume of my starter. Let's say a certain recipe calls for a 2 liter starter, usually I would use 200 grams DME. But if I plan to harvest some yeast from this starter, I'd make it 2.5 liters and add 50 grams more DME. That said, there's been some very good conversation regarding the actual number of cells we're harvesting using this method... see Jbear's comment below
@ Jbear - You make some good points, man. I'm really excited for someone who has the knowledge, skills, equipment, and interest to step up to the plate and count the harvested cells. It's so weird that multiple small volumes of wort will result in more cells than a single flask with even more volume than the multiple combined. Huh.

 

[Jbear]

I stumbled across a fascinating thread that is discussing the very topic of yeast growth in starters. Several people there confirmed what I understood, which is that there is an ideal pitching rate specifically for yeast propagation (which is different then the ideal fermentation pitch rate).
The thread then goes on to question whether sites like Mr Malty or Yeast Calc are accurate, specifically for stirred starters - which both you and I make. Of the science oriented folks, the consensus seems to be they are fairly accurate for still/aerated starters, but some are seeing much larger growth than calculated with a stir plate. And that could certainly explain what you and I see in practice - which is that jar sure looks like more than 40b cells!
Here's the link:
https://www.homebrewtalk.com/f163/stepping-up-yeast-starter-why-393288/

 

[Brulosopher]

@Jbear - Thank you so much for that link, I'm looking forward to perusing it. I'm glad I'm not the only one who seems to think I'm pulling way more than 40-50b cells.

 

[scifi_13]

i think the next starter i make may have this in mind. since i usually go back and forth on 3 or 4 ale yeasts.

 

[RatsoRizzo]

Thanks Bru, been trying to decide the best way to get more than a few brews out of a yeast as I brew small batches and yeast is too expensive at one vial a batch. Think this looks like the best option.
Quick question: when you first pour off 500 ml from the starter and place in the fridge do you have to worry about carb build up in the sealed jar or does the fridge temp stop any fermentation straight away. Don't want any jar bombs in the fridge.

 

[Brulosopher]

@RatsoRizzo - Personally, I've never "worried" about that issue or experienced any problems with it, as I only collect yeast after it is at least almost close to fermented out. Also, mason jars can take some pressure. That said, is it possible to create bombs? Probably, but if your process is good and you're using good jars, I have a hard time seeing how it would happen. Cheers!

 

[Bamsdealer]

The metal on the lid will fail long before the jar does. I know from experience. As far as I can tell, it's not from additional fermentation, mainly CO2 buildup. Just off gas as best you can before you can your yeast. Only one lid bulged in the fridge, the other two failed when I took the yeast slurry out to warm up. Both times I got a faceful of yeast.
Bru, I'm using this method from some 1450. Just now coldcrashing a pint of the starter. The other quart went into a porter I just brewed after work.

 

[oldbullgoose]

Here's a question: I know breweries will use yeast 6-10 times with the best fermentations happening on the third or fourth round of reusing the yeast. What process is going on that improves fermentation and do you get the same effect using this process (which I love...) or might this be an advantage to washing yeast the old fashioned way?

 

[Brulosopher]

@oldbullgoose - Hmm, I haven't a clue, really... but the second and third gens have produced fantastic beer!!

 

[oldbullgoose]

Here's a question: I know breweries will use yeast 6-10 times with the best fermentations happening on the third or fourth round of reusing the yeast. What process is going on that improves fermentation and do you get the same effect using this process (which I love...) or might this be an advantage to washing yeast the old fashioned way?

 

[Brulosopher]

@oldbullgoose - Deja Vu?

 

[barleyfreak]

Great idea. I'm going to try it with my next vial tomorrow. Is there any particular reason the final decant is into a 1/2 pint jar? Would there be a drawback to using pint jars for the final with air space? I possess way more pint than 1/2 pint.

 

[Brulosopher]

@barleyfreak - I don't think it'd matter a single bit, I wrote this up for the person (ahem, myself) who would be purchasing new jars. Actually, if you have the ability and you plan to use the yeast rather quickly, it'd probably be good if you collected a full pint of the starter, which you could then pitch directly into your next batch. Cheers!

 

[humpadilo]

I am pretty new to brewing, 3 months. I think this is really great article and idea. I am deffinately going to start trying this. My wife is just about done with her Medical Lab Tech school and she said she can probably give me a good count of the yeast cells. I think I will try this next week and hopefully post a good count.

 

[Brulosopher]

@humpadilo - I think many of us would truly appreciate a cell count!!!

 

[taekwondd]

I've made a few starters using yeast I've harvested and every single one has been really aggressive. I used to be able to make a 2L starter in my 2L flask but all of the starters I've made with the harvested yeast have blown my foil lid off and made a nice little mess on the counter. I'm assuming it's just because the yeast is much younger than it would be from the vial? I think it's time to buy that 5L flask I've been eyeballing.

 

[mrkrausen]

I love this idea. I've already got a mini fridge filling up with washed yeast as we speak. I wish I would have known about this sooner. And I agree with Taekwondd, I'm gonna need a bigger flask!