When I initially started tinkering with the idea of harvesting yeast from starters, I was unable to find references to anyone else using a similar method. Since I wrote about it, I’ve heard from a number of folks who had been using a similar process, hence I take no credit for developing this method and appreciate all the feedback I’ve received.
Here is the most updated version of how I harvest yeast from starters.
STEP 1
Make your starter at least 24-36 hours before you plan to pitch, I’ve learned that older strains tend to take a bit more time than more recently harvested yeast, so plan accordingly. Using a good yeast calculator, overbuild your starter by 100 billion cells. BrewUnited’s Overbuild Harvest function makes this so incredibly easy, you can even download a spreadsheet version. Usually, the extra amount will be less than or right about 1 liter.
STEP 2
After at least 24 hours on the stir plate (longer if shaken or using older yeast), you can harvest the yeast. Since I like to crash and decant, I always harvest my yeast the night before I brew. To do this, sanitize an appropriately sized Mason/Ball jar using whatever sanitizer you prefer, remove your flask of starter from the stir plate, secure the stir bar using a magnet, and fill the sanitized jar with the proper amount of slurry.
I usually give the flask a good swirl before transferring to ensure homogeneity. Loosely cover the jar with a sanitized lid and place it in the fridge for 24+ hours. This is also the point I’ll move my flask to the cold ferm chamber to crash overnight.
STEP 3
Place the jar in the fridge and pull it out a few hours before you make your next starter. That’s basically it!
Previously, I encouraged people to replace the beer on top of the yeast with pre-boiled and chilled water if they planned to store it for longer than a couple weeks. However, I’ve recently been made aware of some fairly convincing evidence suggesting this is both unnecessary and potentially harmful to the yeast. I started leaving the starter beer on top of the harvested cake and I’ve experienced no noticeably negative impact. For these reasons, I no longer plan to replace the beer with boiled water and recommend others follow suit.
After some time in the fridge, a nice layer of creamy yeast will be sitting at the bottom of the jar.
F.A.Q.
How many generations of yeast can be harvested before it goes bad?
I’ve only anecdotal evidence, so keep that in mind. At the writing of this article, I have two strains of yeast, WLP090 San Diego Super Yeast and WLP002 English Ale Yeast, both have been harvested 13 times. The 12th beer each fermented tasted great with no noticeable differences compared to the original vial. I’ve used this method successfully with ale, hybrid, and lager strains.
What makes this method any better than rinsing (“washing”) yeast?
To start with, I personally think it is much easier and far less time consuming. Additionally, the yeast fermented a wort of ~1.040 OG that had no hops in it, so it is arguably less stressed and ultimately cleaner. I also like that I’m only harvesting a single jar of yeast as opposed to multiple jars that would eventually end up in the trash.
How much yeast is actually being harvested using this method?
I don’t know. I wish I knew, but I’ve yet to find anyone with the know-how to do an official count. As I mentioned before, I’ve been assuming 100 billion cells, though I fully accept this number is likely way off. Still, it has worked great for me.
If you have any more questions or comments, please do not hesitate to ask. Cheers!
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343 thoughts on “Yeast Harvesting”
I’ve recently started washing my yeast in the carboy after racking, but that can be fairly time consuming. This seems like a better method for harvesting yeast, since there is greater control over the yeast growth conditions — potentially ensuring more consistent results between the generations of yeast. Not to mention the time savings.
I’ll be sure to use this method going forward! Thanks for sharing, and cheers!
Once do it, I trust you’ll never go back to rinsing yeast. Cheers!
As for cell counts, I am also very curious about this. I was guessing somewhere around 1.5 – 2 Billion cells / mL dense sediment for ale strains like WLP001. Really hope /u/AIDSGRENADES is able to tell you more!
We’ve been chatting, he’s been working his ass off on this. Last we talked, he mentioned his initial calculations were off and that we may actually be getting closer to 100bil cells.
I’ve been using 2.0 Billion/mL for regular ale yeast, and 2.5 Billion/mL for english and lager yeasts and it has been working out a bit closer. Might even be able to go up to 2.5 and 3.0 but I’m happy being a big conservative.
I’m really excited to have stumbled onto your blog and this method. We share the common interest of simplicity and efficiency.
With the strains that I have brought in from The Yeast Bay and such, I look forward to be able to reap the benefits as you’ve discussed here.
I’m really glad you found a like the blog, thank you so much for reading it!
A quick article on your starter process might be a nice addition to this.
An article on how I make a starter? Hmm, I just figured everyone was already doing that. I use Kai’s stir plate setting at http://www.yeastcalculator.com to determine how large of a starter I need, then add an additional 500 mL to that to pull off later. I then mix 10 g DME per mL of water (so a 2.5 L starter would have 250 g DME), boil it for 10 minutes, chill it, pitch yeast, and put it on the stir plate. Perhaps updating the post with a brief “how-to” might be helpful for some, thanks for the idea!
Just at little comment about the DME amout. 1mL equals 0,001l so 10 grams/mL would be 25kg, like (50lb). 10 grams DME per 100 ml water is the right amount.
I’m curious what the impetus was for this comment, as I couldn’t find a typo anywhere in the post.
The article was fine, my comment was about your explanation about making a starter above.
“. I then mix 10 g DME per mL of water (so a 2.5 L starter would have 250 g DME), boil it for 10 minutes, chill it, pitch yeast, and put it on the stir plate.”
Excellt blog BTW, I’ve just brew a lager using your lager method, still waiting for the results.
Anyone been following this thread as it seems to relate? Thoughts?http://www.homebrewtalk.com/f163/cold-hard-truth-about-rinsing-yeast-boiled-water-451925/
Haven’t seen it and I can’t access HBT from work, but I’m very interested. If you’re up for it, perhaps you could email me some of the more interesting details (brulosopher@gmail.com)? Cheers!
So your article only shows you pulling one jar… what do you do then? Could you just pull 5 jars at once? How long would they stay viable in the fridge? Could you then just take the last one and start the process all over? Great thread…
I’m sure you could and I believe people have. What I like about this method, though, is that I’m taking a small portion and using the rest for a batch of beer, thus my fridge does not become chock-full of yeast. If you do split it up like that, use a calculator every time you make a new starter, as viability will decrease over time.
Love the continued excellent posts. I will admin, I never saw the point in decanting the starter beer, so I’m ahead of the curve on this new breakthrough. 🙂
So, just to be sure.. you are agreeing that I could follow your process, then harvest 5 small jars, and use each as a new starting point for the process? And you reasonably expect that each jar has about the same number of cells that you originally started with? If stored in the fridge, with the original green beer, how long do you expect them to be healthy and viable? This is exactly what I was looking for, thanx!
I sort of agree, but not exactly. If I were propagating yeast with plans to split the entire starter up into smaller portions without using any to pitch into a larger batch, here’s what I’d do:
1. Using http://www.yeastcalculator.com, determine how large of a starter I would need to make to get to 500 billion cells based on the expiration date of yeast vial/pack.
2. Once the starter is completely fermented out, divide the entire volume by 5 to roughly determine the volume containing 100 billions cells (the amount in a typical vial/pack).
3. Clean and sanitize 5 appropriately sized holding vessels (1 pint mason jars would probably work well) then transfer the well homogenized starter solution to each vessel and place them in the fridge.
The key would be ensuring the starter solution is well blended before pouring. Other than that, I think this would work just fine. Cheers!
When it’s time to reuse the 500ml you split off, what are your next steps? Do you decant it before pitching into the new starter?
I usually pull the jar out of the keezer and decant half the liquid while it’s cold (so as to reduce any foaming that occurs as a result of warming), then I leave it on the counter for 3-4 hours to get to room temp. I’ll then calculate my starter size using the date I harvested the yeast and assuming there was 100bil cells. Next, I swirl it all up, throw it into my 70°F starter, and put it on a stir plate.
Thanks for the reply!
Fantastic blog. I started doing this quite some time ago. For what it’s worth these are my only slight differences I do. I chill my boiled in flask started to the same temp as the small jar and then combine them. My hope is to eliminate any shock due to different temps. Also I multiply .089 x the amount in ml of water I use. This is only slightly less than your amount. I do boil for 15 minutes which brings me in at 1.040. Minor differences to be sure. I’ve stopped counting how many time I’ve rebuilt the same yeast. It just doesn’t seem to matter. I’ve brought yeast back to life that was 13 months old. Took a little longer as you say but it works. Usually, as I am boiling my starter I’m also boiling a mason jelly jar, lid and ring for 15 minutes. I lift the boiled jar from the water filled with hot water and cap it until I am ready to pour some starter in it. Of course I pour the water out just prior to adding and capping the new sample which I date and label. Real glad to have found this thread. It’s just always seemed like common sense to do this.
I’m also a microbiologist, if you have any questions shoot me a message. I’ll be posting a lot of stuff about yeast this summer on my blog.
So how long will the yeast be viable when stored this way?
I can only speak from experience, as I’m not a microbiologist, but I’ve successfully used yeast that was harvested from a starter 6 months prior. Just makes sure you take this into account when calculating your starter size at http://www.YeastCalculator.com.
Awesome!! That’s great news. I just harvested my first batch last night, Wyeast 1056. I wish I had known about this a while ago – saves me $6.29 each batch! Thanks for the info!
Awesome information here! I’ve learned from every comment and reply. I’d like to use 1/2 pint jars for my harvested yeast. Why couldn’t you decant the original starter to about half the total, re-stir somehow and harvest into the smaller storage containers? Wouldn’t the cell count be very close to the same?
I see absolutely no reason not to do this, I’ve just been leaving them in the larger jars lately because it’s easier for me. Go do!
Thanks for the quick reply. I’ll respond with any relevant information on my success. I’m starting a log on generations of yeast I harvest and how they preform. Also can’t wait to try your “fast-forward” lager method. Thanks for all you do!
This is exactly what I do. I prefer the 1/2 pint jars because they stack nicely and take up less room.
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I’ve used yeast up to 8 months old with this method.
Any news in the yeast count? Super technique! For the starter, i use some wort that i save in a sanitiZed mason jar after every mash i do. So when i want to do a starter for a recipe i previously brewed, i use the saved wort instead of DME, so this acclimate the starter to the wort it will ferment!
Nothing yet, Jean, hopefully soon. I’ve considered that, but my likely irrational fear of botulism has held me back.
I figured out a way to erase the risk of botulism, when i prepare my starter, i save a part of it. Then, during my mash, i keep the last runnings in a pot which i boil after my batch, i cool it and i pitch it directly in my starter. Ill do this procedure until i get a pressure cooker -_-! Thanks for your great experiment and your professionalism.
Thanks heaps, spent most my morning reading the “cold hard truth” haha.
I’m highly interested in not using a starter (pitching within two weeks) How much harvested yeast is actually needed for a standard 23L 1.045 brew?
I also struggle to understand the yeast calculators.
According to http://www.yeastcalculator.com, a 23L batch of 1.045 wort would require ~250 billion cells. Cheers!
I am definitely going to try this. Isn’t a more consistent method (if you trust your calculator) the following?
1) Use online calculator to figure out how many billion cells you need for your batch of beer based on wort gravity, wort volume and yeast viability. (e.g. a 1 month old pack of liquid yeast pitched into 1 L of wort on a stir plate is enough yeast for 5.25 gallons of 1.050 ale wort – 184 billion cells (mrmalty.com calculator))
2) Adjust the OG artificially upward until the number of cells needed is 184 billion + 100 billion (for your poured off saved yeast for the next batch.) (e.g. adjusting the OG up to 1.079, gives 284 billion cells as the required amount of yeast. the new starter volume required is 2.28 L)
3) Make a starter of 2.28 liters, pitch your liquid yeast pack, grow up.
4) You want 184/284 billion cells for your beer and 100/284 billion cells for your next beer starter, so you swirl the starter thoroughly and immediately pour off 100/284 * 2.28 L = 800 mL of homogenous yeasty wort into a quart mason jar and pour the remaining ~1.5 L of wort into your beer.
Here are the estimates of the number of cells in 500 mL of decanted wort under the following conditions:
OG = original gravity of wort you plan to ferment for your batch (e.g. 30 = 1.030)
volb = volume of batch of beer (e.g. 5.25 = 5.25 gallons)
viab = viability of yeast (76% is one month old and 54% is two months old)
vols = the volume of yeast starter required
yeast = number of total yeast cells in billions that are needed for batch and next starter
500 mL = the number of yeast cells in billions in 500 mL of homogenous wort from the starter made under the conditions listed on the row
OG volb viab vols yeast 500 mL
30 5.25 76% 1.16 212 91
40 5.25 76% 1.7 250 74
50 5.25 76% 2.28 284 62
60 5.25 76% 3.02 320 53
70 5.25 76% 3.79 353 47
80 5.25 76% 4.72 388 41
90 5.25 76% 5.66 420 37
30 5.25 54% 1.82 212 58
40 5.25 54% 2.67 250 47
50 5.25 54% 3.58 284 40
60 5.25 54% 4.73 320 34
70 5.25 54% 2.39 353 74*
80 5.25 54% 2.98 388 65*
90 5.25 54% 3.57 420 59*
*according mrmalty.com, these starters require 2 packs of yeast into the original starter due to the limits on the amount of possible yeast growth
You can have some pretty highly variable yeast counts if you don’t go ahead and calculate out exactly how much of the starter you need to take. If you always use the same OG of wort for your beers and always use the same viability of yeast, you will have consistent results, otherwise, it could vary a fair amount. (This all of course assumes that the mrmalty calculator is pretty accurate and that there is difference in finished beer with pitching rate.) In addition, none of the examples gives 100 billion cells of yeast in the extracted 500 mL volume.
It’s certainly another way of doing it that will likely work great!
Hey, I love your blog. I’m really excited to try this method, but I think I’ve run into a snag with it. I might be making the same point as the previous poster aaron, but I found his comment kind of confusing.
What I’ve found is that this method assumes a linear relationship between starter volume and final cell count, and the calculators available online don’t support that. For example, i need a 900mL starter for the beer I’m brewing on Friday. If I were to increase that by 500mL to reserve a pint of slurry, that would increase the volume of my starter by 55.5% but would only increase my cell count by ~14%. Then if I separated off 500mL of the slurry and pitched the remainder, I’d be underpitching by a pretty substantial margin.
Am I misunderstanding your method?
Thanks for all the great material,
Matt
Good point, one that’s been pointed out by a few people. I wrote it up that way to keep things simple, what I usually do is build my starter to have ~100bil more cells than needed, than harvest that extra amount, which is usually about 1 quart. It’s inexact, to be sure, but I’ve yet to have a problem with this method. Cheers!
Thanks for the response! I ended up doing something similar. I maxed out my 2L flask so I’ll be able to pull off a pint and still have enough to pitch. That pint will not be quite up to 100B cells, but enough to save me from buying another pack next time I brew. Looks like it’s time to invest in a 5L flask…
Cheers man. Keep up the good work with the blog.
I’ve been harvesting yeast from my starters for about month now after seeing this article – thank you for laying it out so well.
I always let my 10:1 ratio starters go for 24-30 hours on a mix plate then pour off enough to fill a pint jar, seal it up and place it in my kegerator (46degF). I just noticed, however, that my first two (of three) jars are bulging the cap. I let the pressure off each and definitely noticed that a fair amount of CO2 had been produced.
Have you experienced this? I wonder if perhaps 46degF is just too warm for the yeast to be stored. Infection is a possibility, but I’ve never experienced issues with my sanitation practices previously.
After I harvest, I’ll cap loosely and leave the jar out of the fridge until all signs of activity dwindle… mason jar bombs can kill!
Since this yields a trub-free slurry, much the same as the original vile, is there any reason you couldn’t just refill the original vile for storage? I understand you’ll have more cells if you have the greater volume of the mason jar, but you’re going to do a new starter for your next brew anyway. And if you store in the vile you have a very repeatable measure of original yeast. Thoughts? Thanks.
I know people who do that, they get what appears to be less slurry, but they’ve reported success.
Hey really like your blog, I’ve been doing this method of yours since this summer. I recently have had the last 3 ‘generations’ of 001 finish high at 1.016, when the first 6 or 7 all finished at 1.010-1.012. should I just buy a new vial at this point? did I somehow damage the yeast? or should I try again and build up a 2step starter or would this just give me an overpitch of used up yeast?
The failure to fully attenuate could be caused by any number of things. What I think would make an interesting experiment would be to compare your harvested yeast (from a starter, of course) to a new vial of 001 in the same wort! If the beers aren’t tasting infected, just a bit sweet, you may want to calibrate your thermometer. I have a friend who went 4-5 batches getting shitty attenuation, thought it was his water or the yeast, then discovered his thermometer was measuring 6°F cool, meaning he was mashing 6°F warmer than he wanted. Something to consider.
Thanks that does give me more to consider. First I’ll calibrate my thermometer for sure. The beers have been great just a tad sweet. I just may do this experiment you suggested too. Appreciate your reply.
I tried yeast washing once; it wasn’t worth the price of buying new yeast for each batch. But THIS looks like the way to go! I will definitely give it a try on my next batch….
I just harvested some yeast, but forgot that I needed time to cold crash and decant before pitching. Now I have wort (Best Blonde Ale) in the fermenter ready to go, but the yeast I harvested needs time to settle. Would it be better to wait 24 hours and then decant and pitch or pitch the whole thing? The batch is 2.3 gal. and the fermented starter with the yeast is 1 pint.
I’d just pitch it!
Thanks very much for sharing this great idea. Too often I’ve found myself paying way too much attention to yeast flocculation levels and steering clear of highly flocculant yeasts. They’re a pain in the ass to rinse.
Thank you very much for this article. I’ve always wanted to wash my yeast, but the by the time I get past my primary it seems like too much work. I think this I can try and keep up with.
Can you help me with one problem I am having with the calculators? Is the growth rate days? I am confused on how you know when your starter is ready. For example here is what I want to do:
Use a smack pack that has 50% viability (50B cells) for a 1.065 5.5gal batch. If I make a 2L starter the growth rate is 7.6. The helps says that you will want to stay around 1 for growth rate. So do I need to step this up multiple days?
For your example making what looks like a 2.5L starter did you just do that for 24 hours? Or was it stepped up?
Thank you for clarifying this.
Hi Peter,
I can help with your questions (I wrote the yeast calculator that the author links).
Growth rate is just a measurement of how many cells you end up with, compared to how many you started with. If you start with 50B cells, and end with 100B cells, you have a growth rate of 1 (you grew as many cells as you started with). If you end with 150B cells, your growth rate is 2 (you grew twice as many new cells as you started with). And so on.
What the help is saying is that if your growth rate is not *at least* 1, then you are likely wasting your time – you’re probably not going to end up with many more cells than you started with.
Growth rate is not hugely important in stirred starters; note that for still starters (i.e. no stir plate, you are not shaking), it’s tough to get much beyond 3, as it takes a long time and the yeast tend to go dormant.
A 2.5 liter starter is going to yield roughly 403B total cells, for a growth rate of 7.06. The inoculation rate is a little low (20 million cells per ml of starter wort), but I’d personally just do it in one step, as you aren’t too far out of range (optimal inoculation rate is 25-100 million cells per ml).
As for how long does it take? Most stirred starters are done in a day or two. Some yeasts will make a nice, fluffy krausen (just as they would in a beer); some will do very little, though you will usually note that a stirred starter will become more opaque as it progresses, due to the amount of yeast cells in suspension.
I personally tend to let my starters run more in the 2-3 day range, whereupon I cold crash and decant before pitching, but that’s probably overkill.
If you have any other questions, lay them on me!
Hi Peter,
I can help with your questions (I wrote the yeast calculator that the author links).
Growth rate is just a measurement of how many cells you end up with, compared to how many you started with. If you start with 50B cells, and end with 100B cells, you have a growth rate of 1 (you grew as many cells as you started with). If you end with 150B cells, your growth rate is 2 (you grew twice as many new cells as you started with). And so on.
What the help is saying is that if your growth rate is not *at least* 1, then you are likely wasting your time – you’re probably not going to end up with many more cells than you started with.
Growth rate is not hugely important in stirred starters; note that for still starters (i.e. no stir plate, you are not shaking), it’s tough to get much beyond 3, as it takes a long time and the yeast tend to go dormant.
A 2.5 liter starter is going to yield roughly 403B total cells, for a growth rate of 7.06. The inoculation rate is a little low (20 million cells per ml of starter wort), but I’d personally just do it in one step, as you aren’t too far out of range (optimal inoculation rate is 25-100 million cells per ml).
As for how long does it take? Most stirred starters are done in a day or two. Some yeasts will make a nice, fluffy krausen (just as they would in a beer); some will do very little, though you will usually note that a stirred starter will become more opaque as it progresses, due to the amount of yeast cells in suspension.
I personally tend to let my starters run more in the 2-3 day range, whereupon I cold crash and decant before pitching, but that’s probably overkill.
If you have any other questions, lay them on me!
Great thanks! Yes, I misread what the growth rate was. Makes more sense now. Thanks for your help and thanks for the website, it is very helpful.
No problem, Peter. I’m happy to help.
Am fairly new to brewing and am always trying to learn new and better ways to do things – This sounds like a much better alternative to washing and harvesting yeast from your fermenter. Do have one question though – why do you cold crash before pitching – is that to make it easier to decant beer from the yeast cake before pitching?
Thanks in advance
That is exactly why! The cold crash encourages more yeast to drop out, meaning I don’t lose that yeast when decanting… meaning more yeast is pitched. Cheers!
Thanks again for sharing your findings and experiences. I wonder if you can help me by answering a question on stir plate speed.
Using yeast calc.com they show 2 stir plate speeds one is called braukaiser and the other is called white. I imagine the braukaiser setting is a fairly furious spin. The dad’s online yeast calc figures on cells created for a certain volume match up pretty closely to the braukaiser setting.
I have a homeade stir plate with no adjustment and I get roughly a 1.5 to 2 inch vortex from the top of the starter. I’m curious as to yours and and any other brewers out there’s stir plate speeds. Sorry for the long question. Any help would be much appreciated.
My guess is stir plate speed doesn’t really matter that much, but I tend to trust Kai’s calculation a bit more than the others, I believe this is what is used on the HomeBrewDad calculator. My vortex sounds to be about as big as yours 😉
Hi
Just found your blog. I’ve been doing exactly the same thing for over 2 years now, and this works very well. I have made lager from one year old yeast and russian imperial stout from 7 months old yeast without any problem.
Good to find simple time saving methods 🙂
Cheers
Erik
I have been home brewing for just about a year. After my first couple brews, I thought what is this stuff I keep dumping out of my carboy after I rack to my keg. After some research, I decided to start harnessing the power of this beautiful and, more importantly, already paid for, yeast. Subsequently, I started harvesting my yeast. I saw a link to this article on a homebrew blog, and I must say it has. Changed my life. Okay, it might not have been that monumental, but it has changed my home brewing experience. Thank you for this article. I love your blog and read it daily.
Ps. I still have apprehension dumping yeast down the drain after fermentation. Something I will eventually get over.
I share that apprehension… stay tuned 😉
This too has really changed things for me. I now have 5 mason jars (vermont ale included based on your recommendation) in my fridge. My wife isn’t too happy but I don’t have any room in my keezer. What I like about this method over the post-fermentation harvesting is that I don’t have to wash the yeast. So much easier.
I recently was made aware of this method through someone linking to it in a brewing forum I frequent. I have to say I too was attracted by the simplicity of it. There’s really nothing that needs to be changed in your brewing method at all, except making a slightly larger starter. How easy is that?
I tried it on my last batch of beer, but I only used a 200mL jar 🙁 Not the best idea, but I have since bought a few pint (570mL) jars, which I will use in future. Also ordered a 3000mL flask. I have a 5000mL one but it’s a bit cumbersome – I’ll reserve that one for lager yeast starters. Either way, regardless of the size of the jar I used, it was as easy as drinking a glass of beer. 😉 Will definitely be doing this on each batch from now on!
Cheers
Just tried a 16 month old abbey yeast, and no problem making a new starter, just a little slower????
Hi,
I got linked to your site yesterday and have since read most of the content. Thanks for producing such an engaging, informative and useful resource.
I love this idea of over harvesting, I don’t know why I never thought of it before and I’ve been messing around with bottom cropped slurries for ages… Doh!
My question is how to know when to take it off the stir plate? Normally I wait until I think the starter beer is fully attenuated, crash, pour off and pitch. Your method seems to advocate pulling the beer off before it’s fully attenuated -is that right? I can see the advantages to this if it is. When I’ve used WLP002 in the past it floculates into big clumps which sink really fast when it reaches FG. Even when it’s on the stir plate you can see these clumps clearly swirling. If you let the starter get to FG before splitting into the jar for the fridge it would be really difficult to ensure you get about 100B cells in the jar because it all sinks so quickly to the bottom of the flask, even immediately after a good swirl.
However if you split before FG is reached, your cell count could be more of an unknown?
Am I making any sense here?
Thanks again for a great site.
Paul
Hi Paul,
I let it go at least 36 hours or until it appears most fermentation activity has ceased. With 002, which I use often, I’ve found that quickly pouring after a good swirl works fine. It’s certainly not an exact science, but it has worked great for me over the year.
You made total sense! I’m just not sure it’s something to be all too concerned with. Thanks for the compliments and support, I truly appreciate it. Cheers!
Just a quick question, as I’m just getting into the yeast harvesting idea. In Step 1, you state that overbuilding by 100B cells will roughly equate to 1L (~1qt) extra. Your first picture shows a 2.5L starter, but once you take out the harvested yeast, you’re starter still has 2L left, meaning only 0.5L went into the mason jar.
As such, wouldn’t it seem that you maybe only have 1/2 as much yeast in the saved portion? Wouldn’t you want to remove the full volume of extra starter created (i.e. 1L)?
Those pics were taken before I heard back from a guy doing cell counts that 500mL resulted in closer to 70-80bil cells, estimated. I assumed 1L = 100bil because it’s easy and since it’s likely more than 100bil, I don’t risk underpitching.
I’ve never been one for calculations so I rack the lees into 330 plastic bottles which works out about one third lees and the rest beer. I use plastic for safety so that if pressure builds up I know by squeezing the bottle and chill then twist top and let gas out. When I want to use I pour the beer to a glass and its usually good to drink. If not I know I’ve got a wrong ‘un. Otherwise it’s in to the starter. These days because I read too much I only keep for a few months but before I knew better I kept many months. I also reused one strain (Nottingham) for more than a dozen repitchs before I lost my nerve! And none disappointed. I keep my yeast library in a dark and cool corner of my garage. The Camra Guide to Home Brewing,p69, suggests adding 60ppm(whatever that is) Sulphur Dioxide,ie metabisulphide or camden tablet for preservative purposes but thats a bit beyond this simple soul. I think put your courage in your bottle and near enough could well be good enough! Never be afraid to try a new idea.
oops,I mean 330 mils, about half pint or a stubbie,each. I did say I’m not one for numbers. I get about half a dozen of these. Very useful if you’re into 1 gallons brews as you can stretch the original innoculation over several batches.
How many generations would you use from the original vial/pack? Great blog. Love all the exbeeriments!
Thanks! I’ve gone as far out as 18 gens with no issues… then I have the yeast away 🙂
wow….Thanks!
Well, I’m about to go down yet another Brulosopher road as I’ve wanted to get into yeast banking for a long, long time. I’ve been terrified of the risk of “things that can kill you” and think I’ve finally put to rest those concerns with enough anecdotal evidence. That said, I would like to clarify a couple things that I don’t think are super clear. First, it looks like you “never” really seal the jar, right? Just pop a lid on “loosely” (I’m assuming securely, here, to fully cover it) but don’t wrench it down with the ring? Second, I see you’ve successfully used 6 month+ old yeast (my minimal target)…was this with the “new” method (just leave the starter liquid) or the “old” method of replacing the liquid with deoxygenated water? Thanks again for all your work!
I usually seal the jar once it’s been in the fridge overnight, but sometimes I forget. Yep, 6 months old using yeast stores under starter beer.
ok, read through all of this, ok, skimmed it all 😉 I’m building a starter right now from a prev. harvested (11/14) batch (the washing method) I have no idea how many yeast cells I started with. About 1/2 inch densely packed yeast in a 24 oz. mason jar. I’m going to harvest some some from the starter using this method. So what was the approximate cell count for both densely packed yeast/ml, and/or yeast slurry/liter? Thanks!
woops, I meant “yeast slurry/ml”
~1.2 billion cells/ml when densely packed.
Any thoughts on doing this with dry yeast? e.g. Re-hydrating the dry, then pitching it into a starter and following the same process as liquid yeast?
Every tried it?
Never tried it. I don’t think you’d even need to rehydrate it. I’m sure I just it’d work great, though factoring the price of DME, it may be just as cheap to buy a new sachet or just pitch slurry from a prior batch.
Interesting point, I hadn’t considered the cost of DME in the equation 🙂
That’s all I’ve used(with the exception of sediment from a 6 pack of Cooper Pale Ale which I built up to a Starter- it turned out very nice). ie the SALAle/Lager range, Coopers, Sterling, Muntons. I think once they’re hydrated and been through a ferment the same reharvest process applies to both wet and dry yeasts.
What about prior to a ferment? rehydrate > add to starter > harvest? Seems like it produce the same results, but just curious if there’s anything to avoid or reasons not to do it.
I know dry yeast is relatively cheap. but if it’s a strain that’s used often, you can still save $3-4 by harvesting.
I’ve done this a couple of times with W34/70, although I wasn’t harvesting from starters at that point. Noticed no negative effects from it in the finished beer. More recently I’ve put a sachet of US-05 into a starter after rehydrating it, then harvesting it. I only used a tiny jar the first time though, so I ended up putting that harvested yeast through another two starters to grow more of it. Probably stuffed it up in all honesty in this instance haha, but yeah no issues with the dry lager yeast going into a starter. I’d do it again but I’m on a pilsner kick at the moment and using liquid strains.
White and Zanesheif, Yeast,p146 describe rehydrating dry yeast followed by pitching. I would do that unless the yeast packet was a bit old. If you hydrate and put into a yeast starter you can satisfy yourself that there is still life in the yeast! Safer than finding out in the fermenter. I have replicated most half a dozen times or more (24 for Nottingham). Why so many? I regularly make1 gallon brews to experiment with styles. I start with half a packet because its less fiddly. I keep the opened packet in an air tight jar in the refridgerator pending use.
Hi, and congratulations for your article.
I’m a bit confused with your explanations and the photos.
You make 1 l or 1/2 l extra starter? You save 1l or half?
When you brew calculate the starter as the same metod if use a new vial with yeastcalculator.com.?
In other way, for example if I want to do a 11 galon lager batch SG 1053 from a half liter I harveshed 4 months ago. Neast calculator says I need 3 steps with a total of 7 liters of wort. Is a big quantity of DME, and time for the steps…… I’m ok?
Cheers! Apologise me english level
In the Yeast Harvesting article, the photos show me making 500mL more starter than needed, which is then harvested. These days, I tend to make a little more just to ensure high cell counts, though 500mL works just fine.
Thanks a lot
I’m harvesting yeast from a starter for the first time and I forgot to separate what I need to harvest from what I need to pitch tomorrow and cold crashed the whole thing yesterday. Now all the yeast has flocculated to the bottom & I’m brewing tomorrow morning. Any Ideas on how to separate the two?
Thanks.
Sure, this is actually how a buddy of mine does it every time. Just prior to pitching, swirl the yeast slurry to fully homogenize it then pour some into a small mason jar, maybe 1/2 quart or so.
Thanks ! I did it yesterday and it worked perfectly ! This is a great Idea that will save quite a bit of money on yeast.
Would you happen to have a picture of a 500ml Masson jar and overbuilding by 100billion cells.
I’m curious because once it’s cold crashed and in the fridge, compressed, I get about 30ml of yeast, every time. Its nice and compact, and the beer is clear as day. If I use 1.2bill cells/ml it means i’m not getting more than 40bil cells, which almost seems impossible…
When I pour it in and it just starts to hit the bottom, the yeast line reaches past the bottom of the word ‘Masson’ on the jar, and it’s all milky, still, like your image, but once densily packed, i get 30ml or so as mentioned.
It’s on the Yeast Harvesting page, toward the bottom. While we’ve never done precise cell counts, there’s some estimates harvesting the amount recommended in the article will get you between 80-100bil cells.
I may be wrong, but I believe the 1.2bil cells/mL has to do with dense slurry, not necessarily from a starter.
Seeking some clarification. After you make the initial extra large starter, it is my understanding that you pitch a portion into your wort and save a portion to be used for another batch at a later date.
My question goes to your process when you use the saved portion. Do you again make an extra large starter using the saved yeast from the first starter and then pitch a portion and save a portion to be used at a later date? Is that how you are getting multiple generations?
Thank you,
John
That’s exactly right, John! I assume 80bil cells and propagate a new starter based on that and harvest date.
Thank you for the clarification. It’s a good idea that I am definitely going to adopt.
John
Fantastic write up and awesome comments. This is super helpful.
I have a question about yeast viability dates:
With your method, are you resetting the manufacturing date after you make the over-pitched starter? For example, if the manufacturing date was May 1, and you made an over-pitched starter on June 1 – would you put a May 1 or June 1 date on the yeast saved for later?
I am trying to figure out what “manufacturing date” I would calculate starter size and assumed cell count from.
Thanks and great work!
Thanks! I use the latest harvest date as the manufacture date, so June 1 in your scenario. Cheers!
I do this but rather than storing in the fridge, I re-suspend the settled and decanted yeast in 100 mls of wort with 30% glycerine from organic food store (boiled for 15 minutes and cooled). I then dispense into 10 tubes with sanitized turkey baster or sterile pipets and freeze. I break out one tube for a 24 hour 1 L starter. Frozen yeast cell bank.
I just tried the “homebrewdad” calculator in a comparison with the Mrmalty calculator. I then made a starter using what homebrewdad said to use. The resulting yeast mass after chilling in the fridge matches the mrmalty predictions much more closely. I AM using the mrmalty “repitch from slurry” to estimate how many cells I actually grew based upon my volume. Have you just grown up a starter and compared the yeast mass you get without pitching any of it? The homebrewdad calculator gives you great beer, but this one test seems to support the mrmalty calculator accuracy unless the mrmalty estimate of cells/volume is also inaccurate.
I’ll admit I’ve been going mostly off of my anecdotal evidence- BrewUnited calc has never let me down, so I keep using it.
I don’t really care how much yeast i’m growing, just how my beer tastes. maybe the pitching rates required need to be adjusted somehow.
Some results about old yeast. I have collected yeast from starter, and have counted with miroscope live cells from 18 months storage in fridge. In 300 ml, there were 1 billion live cells, 5-7% alive. Made a small starter (100 ml) and the number went to 22 billion, another small starter (400 ml) went to 85 billion cells, next is around 1 liter (not finished yet). Before, I used to make a big starter right away, but I think stepping up is the way to go to get enough cells, at least from very old yeast.
Great information, thanks! I’ve been on a vitality starter kick lately, even with older yeast, it’s been working great.
So, you just take a tube of any age yeast and make a 1L starter and then pitch the old yeast into the starter 4 hours before the pitch time and pitch it all in? How high of a gravity have you used? How about how old of a yeast? lagers?
The yeast should be relatively fresh, the starter should be placed on a stir plate for those 4 hours, the highest OG where I’ve seen this method used was 1.075 and it worked great, I’ve used yeast harvested 3 months prior, and I’ve yet to use the method for lager (it will happen).
Thanks for the great article, I have been washing yeast from the bottom of my fermenter for a while now, and this makes the harvested yeast so much cleaner and easier to work with. I also wanted to say thanks for the link to the Homebrew Dad’s Online Yeast Starter Calculator this is a great calculator which allows the user to design an overbuilt starter to fit their needs. I tied your method this weekend in anticipation of brew this week, I now have my 2lt yeast I am going to pitch crashing in fridge along with the extra so that I can decant that down to a 500ml bottle of harvested yeast ready for the next starter, and just like that done.
Oh and way to represent the Central Valley with your blog.
How does dry hopping affect the harvested yeast? I ferment in a carboy and just throw in the pellets.
Have you ever harvested using a siphon? I ask because I want to harvest before dry hopping and without transferring to a secondary.
I have not. The method discussed on this page involve stealing some yeast slurry from an over-built starter. When I harvest from the cake of a fermented beer, I still don’t rack to secondary, I just pour about a pint or so of slurry into a sanitized jar and toss it in the fridge.
That’s what I do. Just save some slurry, toss it in the next beer. I’ve learned to use plastic sample jars though, as pressures still build up over time. More recently, I pitched 2 packets of abbey yeast into 20 litres of 1.058 wort. One pack was 2.5 years old, the other about 13 months. No starter, just straight in. Beer took a few days to kick off, but kick off it did. A kilo of candii sugar was added midway, and attenuation hit about 84%. I popped another brew on the yeast cake, which kicked off within a few hours, and finished in 2 days. Now I have loads of yeast which I’ll package and hand out to brewing mates.
Prolly dumb question here but I will be doing this on the next batch. In step 2, why do you state “loosely” cover the jar with lid? If so, when do you tighten the lid? Thanks..loving the info here..
The yeast may still be consuming residual sugars in the starter beer, which already contains some CO2. By loosely covering the jar, you’re ensuring it doesn’t… explode. It’s really just a safety measure I take. I usually put the lid on, screw it pretty tight, then back off a quarter turn, just enough to let the gas escape. And I leave it that way until next use.
Thanks Marshall, certainly makes sense. Another question.
The calculator tells me I need a 2 liter starter to get 300 billion cells to overbuild by 100 billion. I save 1/3 of that starter to use in the next starter batch correct? That’s what makes sense to me to get my estimated 200 billion cells into beer and estimated 100 billion harvest correct?
This goes a bit against the recommendations I make in the article, but lately I’ve just been overbuilding by 1 quart and harvesting that amount. But I’ve also been using very fresh yeast, usually only 2-4 weeks since the prior harvest, and my guess is I’m actually getting a bit more than 100bil cells in the jar. It’s sloppy, but it has been working well for me.
The BU calculator should tell you the precise amount to harvest in order to get the predicted 100bil cells.