Yeast Washing Illustrated -- REVISITED!!

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grndslm

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I see much confusion in the original thread that has persisted throughout a 142 page thread. I actually read ALL the posts, and THIS is condensed knowledge one must realize to have success with yeast washing.

--- NOTES ---

+ Technically, this is called "yeast rinsing", not "yeast washing". Yeast washing involves using acid(s). However, I will continue to call this yeast washing, because that's what the majority of users here refer to it as.

+ Not only is yeast washing good for storage of approximately 1 year [or so] in the fridge, but it also cleans a yeast cake that will be "re-used" for an entirely different recipe.

+ If there is anything that is confusing at all from the original "Yeast Washing (Illustrated)" thread, it would have to be at what point do you refrigerate?? The guide is actually quite clear, but in the thread, some people are refrigerating the large jar or not refrigerating the small jars. If you can understand at what point do you want to refrigerate, then you can understand yeast washing.

+ Also, decant means "to pour slowly".

+ Be careful when boiling the glass jars. If you allow them to form "dry pockets" underneath an upright jar, it will likely scorch your pot.

+ Can you forgo boiling the glass jars and just use star san and bottled water? Probably so, because others have reported success. However, boiling sterilizes, which I think goes one step past sanitizing. Boiling the water also removes some oxygen, which causes the yeast to rest easier.

+ Some people put their carboys on their side after adding the boiled & cooled water. This means that tipping only minimally disturbs the trub. Others, who use Ale Pale buckets, have had success in adding the water, then just pouring to an entirely different container (1 or 2 gallon jug?) that is easier for pouring. Others have had much success with siphoning. Just do whatever is easiest for you to leave the trub behind. It's really that simple.

+ When filling your final jars, make sure there is NO HEADSPACE!!! Just have a bit extra boiled & cooled water ready, in case!

+ You can use jars, tubes, & vials as small as you can get with an extra step of decanting, but leaving a slight bit of water to swirl the yeast around.

+ There are some highly flocculant strands of yeast that will actually fall quicker than the trub. For these strands, you have to move a bit quicker when trying to separate the yeast from the trub.

+ **Nobody** can answer how much yeast YOU are collecting. There is a WIDE range of volume (mililiters) that you could be collecting, affected by numerous variables, such as how much beer you leave in the carboy [before adding water], what type of yeast you use, how long the yeast has been in the primary, etc. You MUST use Mr. Malty's calculator to figure out how many yeast cells YOUR washed yeast has.

+ Someone said that they pitched one of their final jars, which had been in the fridge for about a month, WITHOUT A STARTER... and it was fermenting in 12 hours. The typical recommendation throughout the thread has been that up to a week, a starter isn't necessary... but DME is a lot cheaper than the time and money put into a spoiled wort, which is why it is virtually always recommended.

+ The range people will keep washed yeast [for a yeast starter] in their fridge can vary from 6 to 24 months, but I think that the VAST majority of people will discard past 1 year. If you plan on keeping past 1 year, then you need to look into yeast freezing. Use glycerine or glycerol, NOT glycol!!

+ Here are some of my favorite posts from the original thread...

Actually what you missed is contained in the photos of the process. When you pour the contents of the fermenter into the big bottle as it sits in the bottle for about an hour you will get basically three layers. You have to look for them to understand. There is the muddy water layer that takes up the vast majority of the bottle. Good stuff here - you want this. 2. a secondary layer layer of yeast at the bottom of the bottle. Good stuff here too and 3. If you look closer at that sedimented layer it itself is divided in two with the bottom layer being slightly darker . This is the bad stuff that you do not want to go on to the next bottle.

The OP does not tell you to refrigerate the first big bottle. YOu do not refridge until the process is complete and you are storing it. Otherwise the yeast will fall out of solution onto the trub and it will be harder to separate.

Your whole purpose here is to catch the lighter yeast while they are still in suspension and the heavier debris has precipitated to the bottom. You should be pouring cloudy liquid to your next step, not beer looking stuff. If it looks like beer you waited far too long.

I just posted my own yeast washing experience with pictures. A poster thought it might be helpful to post a couple of my pictures here, so here I am :)

This is what it looked like after I had added the water to my fermenter, swirled and let it sit for the 20 minutes. I put it on its side to make pouring off easier (note the towel underneath to keep it from rolling. I'm not going to be responsible for a sudden rash of glass fermenters rolling off counters to their doom). There was a definite delineation between the trub and yeast.

washing5.jpg


And after I poured off the top part into the 1/2-gallon growler and let that sit for 20 minutes. Again, a clear layer of trub, but a much smaller percentage this time.

washing7.jpg


-Joe

What is the proper nomenclature for the generations? Is the smack pack/vial the '1st generation' or is the first harvested yeast the 1st gen?

I just grew a starter with some SmackPack->Harvest->Harvest yeast (2nd gen? 3rd gen?) and it was the healthiest starter I've ever had. Good stuff. I have gotten about 10 batches out of one smack pack of 1007 german ale now. All of them have turned out very nice. Thanks for this post! Another nice addendum would be the brew strong podcast on yeast washing.

I've modified my technique a bit now. I dont throw any water into the carboy, just use the beer thats in there to swirl it up. Then I pour as much of the trub as I can into my half gallon glass milk jar, leave that in the fridge overnight, then decant that and rinse in there (pour in the sterile water, shake like mad), then settle that for 20-30m and decant the free liquid into 3-4 half-pint jars. This has been working great for me. I really like yeast washing, it's fun!

A full Pint = 473 mL (from the calculator I am using....varies on what country you are in, for what a "Pint" is)

So a half pint is 260 ish.... lets say you can actually fit 125 mL of slurry in a half pint jar, with wort on top. Also - this is washed yeast.

The Mr. Malty calculator says not to go below 10% for a "non-yeast percentage" with washed yeast. Lets be conservative and say washing yeast is hard, and you are at 20% non-yeast.

I'm leaving the yeast concentration slider in the middle. Defaults are good. I don't know what thin or thick slurry is.

I harvested my yeast 1 week ago, to use today. That makes the viability at 83%.

For a 1.048, 5 gallon batch, I would need 98 mL of slurry. Lets round that up to 120 mL. That 22 mL increase, increases the estimated yeast count from 168 billion, to 207 billion. Everyone here agrees it is hard to estimate the number of viable yeast cells in your slurry, so over estimate.

This still means if you are using a half pint jar, depending on the measurement of actual washed slurry, you should be good. Technically, if it is only a week old and using these calculations, it is equal to a new yeast vial that has had a starter. If its older then a week, you may want to use less and use a starter, whatever. (And most will say here, always use a starter)

But depending on your method, half a pint jar is fine, and could be setup to be ready for a 5 gallon batch.

Unwashed yeast cakes don't last long in the fridge in my experience. The literature ("Yeast") suggests keeping unwashed yeast for up to a week. I tried to save an unwashed cake for 3 months and it was completely dead when I tried to revive it on my stirplate with 1.030 wort. So if you expect to brew within a week, go for it. But if you want to store yeast for months and months without worry, wash it. It only takes 30-40 minutes (during which you can walk away and do whatever you want) if you have some boiled, canned water just sitting in the back of your fridge.

Baby food jars.

It's an extra step, but after the pint jars sit in the fridge for a couple of days or a week, I just decant most of the liquid and pour off into the sterilized baby food jars. TONS of space saved. Cheers y'all!
Good score .. storage space is a challenge, so I switched to these

I'm confused and I tried to search through all these pages on this thread to no avail so hopefully some experienced person won't mind helping me out. In the above statement you say that by mixing the trub with water the heavier hop particles and other junk settle back to the bottom of the jar. Then in the next sentence you say that if you pour the liquid off the stuff thats settled you'll have mostly yeast. That doesn't make sense. So when I see those pictures, I can clearly see stuff has settled but I don't know what the yeast is, the stuff that settled or the stuff on top. I think i saved mostly the stuff on top and now i'm worried that i threw all the yeast out and I'm saving junk!
You are confusing the layers during washing (keep the liquid, throw away the solid settled layer) with the layer left after putting the washed yeast in the fridge (the settled layer is the yeast). While you are washing the yeast stay in suspension longer than the trub and other junk, so when you shake it up and let it settle the trub sinks. You then decant the liquid containing yeast and water into a new container. When you put that in the fridge overnight the yeast will finally settle and you will see a creamy white layer that is your yeast.

So I have a question about calculating how big a starter to make. I'm looking at the Mr. Malty Pitching Rate Calculator. I go to the repitched slurry tab, I assume.

Should I just use the default settings on the two sliders? That is, how do I know my yeast concentration and my non-yeast percentage?
You only use the "repitch from slurry" tab if you are using washed yeast. But you also need to input your OG, gals, and harvest date of slurry. Once you do this, you will see the # of cells you need (in billions) and the quantity of thick yeast (in ml.) that you will have to build up to to have an adequate pitching amount. Since I generally use washed yeast, I'm only concerned with the milliliter amount. For instance a 5 gal. 1.060 batch using slurry harvested on Feb. 6, needs 208 bill. cells.
Since I only use the thick yeast that has settled in the bottom of my pint jars, I move the "yeast conc." tab all the way to the right. Notice that the ml. quantity goes down to 111 ml. This helps me because now I know exactly how much I need without any liquid. I don't worry about the bottom tab because when you move this back and forth, it only changes your yeast quantity a little bit. Since my samples are pretty clean, I just leave the tab in the center and use that number. Looking at my example here I have about 40-50 ml. of the yeast on the bottom. Since I basically need to double the amount I will do a 1200-1500 ml. starter and it will get me close. When I add the yeast to the starter, I dump all of the top liquid down the drain first.
This is my way of doing it but there can be many others. This just works for me. Hope it helps.

View attachment 51361

I love the look of Wolverinebrewer's washed yeast. Looks like 100% yeast. How and how many times was that washed?
Only once.
My process is easy and takes about 45 minutes including the 30 minute wait time for the trub to settle. Anyone can do this.
I learned how to wash from this thread but using this method I found that I was getting too much trub and small amounts of yeast. Also, I could never get it clean because of the wave action resulting from pouring from the jars. So now I do not pour from jars.
After bottling, I always want to fill 8 pint jars. In order to get the highest concentration of yeast suspended, I only boil and cool 140 ounces of water and add that to the fermenter with the yeast cake. I put the top on and shake until the cake is all broken up and in solution. The liquid will be greenish. Let it set 30 minutes. The heavier green trub will settle out and you should see only peanut butterish color liquid. Now you can siphon that off into your jars. Sanitize an auto siphon and put a 24" hose on the end. Either boil or sanitize your jars. Put the black tip of the siphon just under the liquid and pump on the siphon while keeping the outlet hose in one of the jars. This process is easier if you have a helper because its hard to hold the hose and operate the siphon but it can be done with one. Once the yeast is flowing, use one hand to slowly lower the siphon keeping it just under the surface. Use the other hand to move the hose from jar to jar. Once all 8 jars are filled the siphon should be just above the green trub. If done right, the tip of the siphon should not have disturbed the trub layer. Now, take a sanitized paper towel and wipe off the rims of the jars. Then dry off your still boiling lids and place on the jars and add the rings. After three days the yeast will settle completely and be nice and clean.
I do want to say that that pic. is either S-04 or US-05 because that is what I use most often. I can't comment on whether my method works for other yeast strains.

It will work for you.
Remember, time is your friend. Yeast will stay suspended for quite awhile so if you need to give the trub more time to settle, it shouldn't be a problem. Just don't rush and cut it too short.
And if you can do this without moving the fermenter and disturbing the trub, your jars will come out very clean.....as long as you don't suck any up. :)
One more thing. Determine how many jars you are using and only boil about 16 ounces of water more than you need to make sure you get a high concentration of yeast in each jar.

And sanitize well!
 
This is a great comprehensive post. It will definitely help people who don't have time to read through all 140+ pages. I found myself trying to go back through that thread the other day after washing WLP002...stuff drops like a brick!
 
This is a great comprehensive post. It will definitely help people who don't have time to read through all 140+ pages. I found myself trying to go back through that thread the other day after washing WLP002...stuff drops like a brick!

That is definitely one area I would like to expand on.

What is the best way to separate those "highly flocculating" strands from the trub??

There was actually another thread (only 2 pages long, tho!) dedicated to that subject, but I didn't copy it down. The information in there wasn't very definite, and I wasn't exactly planning on doing this until I got a third of the way through it.
 
Very cool of you to take the the time to do that. Please don't be offended when I say...S-T-R-A-I-N-S.
:D
 
That is definitely one area I would like to expand on.

What is the best way to separate those "highly flocculating" strands from the trub??

There was actually another thread (only 2 pages long, tho!) dedicated to that subject, but I didn't copy it down. The information in there wasn't very definite, and I wasn't exactly planning on doing this until I got a third of the way through it.

Not sure, I think the consensus I saw was that you were gonna keep a little trub no matter what and the best plan of attack was to minimize the trub and cold break that goes into the fermenter. Thats if you know you are going to rinse it ahead of time.
 
Everything you need to know about "rinsing" . . .
Except for this.
+ Also, decant means "to pour slowly".
Decanting has nothing to do with speed. You can pour off the liquid as fast or slow as you like as long as you get seperation and don't disturb the sediment.

Just saying, because after this thread, it's clear that the obvious is not always so obvious. Very possible that someone might pour the entire solution, but do it slowly.
 
Very cool of you to take the the time to do that. Please don't be offended when I say...S-T-R-A-I-N-S.
:D
You have a suggestion for a strainer that separates the yeast from trub & broken down pellets??

Except for this.
Decanting has nothing to do with speed. You can pour off the liquid as fast or slow as you like as long as you get seperation and don't disturb the sediment.
It looks like you may be technically correct... :mug:

Google -- define:decant
de·cant /diˈkant/
Verb
1. Gradually pour (liquid, typically wine or a solution) from one container into another, esp. without disturbing the sediment.
2. Empty out; move as if by pouring.
 
I think the only real question I have that was never asked in the original thread is...

- If one were brewing beer around yeast rinsing (strange, I know), what would be the optimum time to rack to the secondary, yielding the greatest volume of salvagable yeast possible in the primary??

As close to the "end" of vigorous fermentation as possible? 7 days? 10 days?
 
Even if you are brewing around yeast rinsing your first obligation is to make sure the yeast have fully fermented the beer. I'd say as soon as the fermentation is done might be an optimal time to harvest the yeast.
Honestly, I don't think there will be any appreciable increase in viability of the yeast whether you harvested right after fermentation or kept the beer in the primary for the whole time and then harvested.
Harvesting yeast after the beer has been in the primary, for what ever time the beer requires, has worked for many people including John Palmer and Jamil Zainasheff.
 
First off, great thread (and great original thread).

So I want to reuse some yeast from one of my saisons I brewed this spring.

I made a 10% wort solution with 500 ml of water. Pitched the dregs from 2 bottles into the solution. Let it sit about 2.5 days (yeast became active again).

I just swirled up the solution and let the trub settle out. Made a 1 quart starter with 4 oz of DME, and decanted the small solution into the new big one today.

I don't want to use this yeast for another month or two, so I want to wash it.

I know how to wash, the question is just WHEN should I do so? Wait 2-3 days for the starter to get going then wash? I don't want to dilute the yeast too much, and want to harvest 2-3 pints full. Also, how would I have any idea how much yeast i would actually have after washing?

Thanks!
 
All I can tell you is... I would want to plan on letting the yeast separate for 3 to 7 days before decanting the "beer" on top.

We decanted the beer after just one day, because we were in a hurry. We could have gotten twice as much as we did, I'm sure.... had we let it sit for a few more days.
 
southside2234 said:
.. the question is just WHEN should I do so? Wait 2-3 days for the starter to get going then wash?
Also, how would I have any idea how much yeast i would actually have after washing?
1) depends how quickly that particular yeast flocc out.. a lot of factors.. like the poster above me said, longer allows you to gather more yeast.
2) Note #10 or 11 in the OP answered this.. no one here knows. When it is done, you can measure it.

good luck!
 
I am interested in starting to wash my yeast but I admit, I haven't taken the time to read thru any of the 140 pages of the original thread this OP was referencing to so forgive me if my answer to my question is in there.

My question involves when to wash my yeast? I watched a video where they said that you should do it when racking from primary to secondary. My question is, what if you don't transfer from primary to secondary? Most of my brews I keep in my fermenter bucket from the time I rack the wort until I rack to my bottling bucket. Will this be OK or would I have to start racking my beer to a secondary vessel if I wanted to start washing my yeast?
 
I am interested in starting to wash my yeast but I admit, I haven't taken the time to read thru any of the 140 pages of the original thread this OP was referencing to so forgive me if my answer to my question is in there.

My question involves when to wash my yeast? I watched a video where they said that you should do it when racking from primary to secondary. My question is, what if you don't transfer from primary to secondary? Most of my brews I keep in my fermenter bucket from the time I rack the wort until I rack to my bottling bucket. Will this be OK or would I have to start racking my beer to a secondary vessel if I wanted to start washing my yeast?
IIRC, if you want to keep your yeast in PRIME / OPTIMUM health for as many generations as possible... you will want to transfer to secondary.

As with anything else brew related, however... there's always somebody who will say that it's possible. I once saw a thread of a guy who used ordinary, rusty 55-gallon steel drums to brew beer in... but I don't think I'd do it myself.

Then again, optimum beer result will be to forgo secondary and keep it in primary as long as possible, primarily to prevent oxidation... which I'm sure you're aware of.

Perhaps the proper answer to your question is actually.... a cheap 15-gallon conical fermenter with yeast catcher???

There must be a reason that the pros use conical fermenters, and your question could very likely be the culmination of their knowledge into a PRIME / OPTIMUM solution. . . . .
 
That is definitely one area I would like to expand on.

What is the best way to separate those "highly flocculating" strands from the trub??

There was actually another thread (only 2 pages long, tho!) dedicated to that subject, but I didn't copy it down. The information in there wasn't very definite, and I wasn't exactly planning on doing this until I got a third of the way through it.


Not sure, I think the consensus I saw was that you were gonna keep a little trub no matter what and the best plan of attack was to minimize the trub and cold break that goes into the fermenter. Thats if you know you are going to rinse it ahead of time.

I just experience this with a lager yeast. In the second jar, Some white yeast settled at the bottom then trub then cloudy liquid. I poured off the cloudy liquid into another jar and saved it, then discarded the trub and saved the white yeast at the bottom as well and recombined them when I pitched.
 
So if you keep your yeast for say, 6 months, should the starter be bigger, longer or both? I don't plan on keeping mine much past 3 months but I wonder if a 24 hour starter is long enough to get where I need to. So far, I've made 1 beer with 3 week old yeast and it's perfect. But moving forward, I feel very intimidated working with this yeast. I guess time will tell and my confidence will grow as well.
 
Beer-lord....

Good beer will be had with a starter, designed around estimates from the Mr. Malty Calculator [or similar] and a little bit of your own intuition and scientific understandings.

No need to rush good beer, my man.
 
Awesome culmination of information, nice work! I read the original thread, and others, and the advice in this summary really helped.

It would be awesome if the forum had the ability to vote for posts. Then it could be sorted by highest vote count to bring more meaningful info forward.

Sticky would be a good idea. :)
 
Great compilation of questions! Just curious, what happens if I left some head space? I didn't realize that we were supposed to fill it all the way up. Thanks.
 
If you fill it all the way up there is no oxygen to get mixed in with the water (beyond what it will have nearly no matter what you do). On the upside, some of this oxygen gets eaten by the lid that it's in contact with and creates rust... On the downside... The liquid is in contact with the rust.... It doesn't seem to be problematic or harmful though.

Leaving headspace will definitely increase the amount of oxygen that the water can absorb. My impression is this is far less desirable than having the potential rust (which hopefully is minimal if you have followed the instructions). You could try doing it under CO2 perhaps and eliminate some of this alternatively. If CO2 is all that is in the headspace you shouldn't have any issues with it.

In any event, people have done it with success either way. No headspace is just trying to create the optimum conditions.
 
Thanks all for the helpful tips on this subject! I gave it a try yesterday when transferring a Cali Common to secondary. At first I thought I had too much trub in my mix, but looking at it today after it had a bit longer to settle it looks better.

View attachment 102847


The bottom layer was all one color until I moved the jar for better lighting for the pic. That created the white-ish layer in the middle.
 

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OK, so my buddy and I got some yeast from a local brewery today. They filled up a peanut butter jar about 20% or so, and my buddy's like.... "Let's just pitch it!!" I said, "Hell no!"

We get home, I boil enough water for 2 small glass jars and 1 larger jar. The intent was to put the washed yeast in the 2 smaller jars and just have the larger jar for a slight extra in the washing process, as well as to have some for when we wake the yeasties tomorrow or whenever we decide to brew. Threw in the water from the 2 smaller jars and just enough extra. Not sure how I decided on how much extra water to add (guess it just looked right), but it ended up being the perfect amount in the end, really. I tilted the peanut butter jar on its side so the trub would fall to the corner of the jar, with there being a rubber slip-free mat on one side and put a rag underneath the opposite corner holding the peanut butter jar at an angle. The trub all fell in the corner as planned after a very short time, like a few minutes. Definitely less than 10 min. My buddy is very impatient and encouraged me to decant into the two glass jars. Don't think there was any urgency, but I did feel like most of the trub had settled already in that very short period of time, considering this is only a peanut butter jar we're talkin about washing in.

Anyway, after just 5 hours we've already got plenty of pure white yeast for two 5 gallon batches. I'd say there's at least 3 tablespoons in each jar, and the top liquid is still cloudy.

Now my real question is.... HOW IMPORTANT IS IT TO WAIT UNTIL THE TOP LIQUID IS CLEAR???

My buddy is, of course, rushing our process so that we can brew tomorrow morning. I said we shouldn't do it until tomorrow night, at the absolute earliest. 5 PM will be the 24 hour mark.

My theory is that you want the top liquid / beer to be as clear as possible, because you want the least flocculant yeast to remain with the most flocculent yeast that have already bottomed out after 5 hours.


One of Wolverinebrewer's posts in my OP states:

"After three days the yeast will settle completely and be nice and clean."

So my question is can yeast make it longer than 24 hours?? If there are yeast that can keep on "kicking" for more than 24 hours in a fridge, then wouldn't those be some of the most healthy and important yeast that you'd want to settle before decanting the top liquid???

Any thoughts on this?
 
Anyway, after just 5 hours we've already got plenty of pure white yeast for two 5 gallon batches. I'd say there's at least 3 tablespoons in each jar, and the top liquid is still cloudy.

Now my real question is.... HOW IMPORTANT IS IT TO WAIT UNTIL THE TOP LIQUID IS CLEAR???

My buddy is, of course, rushing our process so that we can brew tomorrow morning. I said we shouldn't do it until tomorrow night, at the absolute earliest. 5 PM will be the 24 hour mark.

My theory is that you want the top liquid / beer to be as clear as possible, because you want the least flocculant yeast to remain with the most flocculent yeast that have already bottomed out after 5 hours.

One of Wolverinebrewer's posts in my OP states:

So my question is can yeast make it longer than 24 hours?? If there are yeast that can keep on "kicking" for more than 24 hours in a fridge, then wouldn't those be some of the most healthy and important yeast that you'd want to settle before decanting the top liquid???

Any thoughts on this?

You make some valid points, but my questions are 1) will it make a big difference in the beer if you out the liquid in too? If not just pitch it all in. 2) what yeast is it? If it's a really strong fermenter like the California ale yeast, you'll be fine pitching slightly higher flocculating yeast.
 
You make some valid points, but my questions are 1) will it make a big difference in the beer if you out the liquid in too? If not just pitch it all in. 2) what yeast is it? If it's a really strong fermenter like the California ale yeast, you'll be fine pitching slightly higher flocculating yeast.
Awesome questions.

We just pitched the whole jar (half pint?). It got 97% of the trub out that we wanted out. But 10 minutes to settle in the peanut butter jar was still not enough for it all to settle. Still recommend 20 to 30 minutes to truly separate yeast from trub.

We'll have to figure out what type of yeast it is, tho. Forgot to ask that. :cross:
 
I've been trying to find out when the preferred time to pitch the top liquid (beer) after the yeast has been refrigerated.

EarlyAmateurZymurgist has suggested that you don't want what's in that liquid after a day or so??

https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/index42.html#post5512428
Preferably, one doesn't want to carry the least flocculent yeast over to the next fermentation. In a pure culture, the least flocculent yeast cells tend to be respiratory-deficient mutants.

The photo shown below contains a plate that I streaked from a yeast culture that was harvested from a bottle of bottle-conditioned beer. The small colonies are more than likely respiratory-deficient mutants (a.k.a. petite mutants or simply "petites"). The colonies in the rectangle are the reference culture.

PlatedYeast_zps10c1ab8c.jpg

https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/index43.html#post5512863
It's common knowledge that the least flocculent fraction of a pure culture is composed mostly respiratory-deficient mutants. That's why crops are taken from the middle of the yeast layer in the cone of a conical fermentor.

A Wiki entry on petite mutation (I know, Wiki is not a citable source):

http://en.wikipedia.org/wiki/Petite_mutation

A seminal paper on respiratory-deficient mutants is:

Respiratory Deficiency in Brewing Yeast Strains-Effects on Fermentation, Flocculation, and Beer Flavor Components. José R. Ernandes, John W. Williams, Inge Russell, and Graham G. Stewart

So anywhere from a few hours to a day seems totally acceptable and actually preferred when washing yeast. Because the boiled water should have no oxygen, the REAL yeast should fall to the bottom rather quickly... and actually keeping whatever is still floating around in there past a day more than likely IS a mutant!!

I think he and I will have to agree to disagree, however, that just pouring the yeast cake into jars is more beneficial than washing yeast.... https://www.homebrewtalk.com/f163/saving-yeast-432059/index2.html#post5516364

http://woodlandbrew.blogspot.com/2013/01/abv-effects-on-yeast.html
ABV+vs+Time+yeast.png
 
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