Saving yeast
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beergolf
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Sticky at the top of this forum....
https://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/
https://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/
Most people refer to it as washing yeast. There is a ton of information on different methods around this forum and it is really easy to do. Do some searches for yeast washing and check out the sticky that beergolf linked too and you'll be in good shape.
EarlyAmateurZymurgist
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If I were you, I would skip washing the yeast with boiled water. No professional brewer washes his/her yeast with boiled water. Washing yeast with boiled water does nothing but invite trouble, as boiled water is nowhere near as sanitary as beer.
All one needs to do is to leave enough liquid behind in one's primary fermentor to able to swirl the solids into suspension. As with the yeast washing process, one should wait a few minutes for the heaviest fractions of the trub and dead yeast cells to settle out after swirling before decanting the liquid into a well-cleaned and sanitized container. One should wipe the lip of the fermentor over which the "crop" will be poured with grain or 91% isopropyl alcohol before decanting the liquid (think about what a nurse or doctor does before he/she inserts a needle into one's arm).
Contrary to what most homebrewers have been led to believe, the culture needs some of the protein from the trub to remain healthy and beer is a much better environment for the culture than water, as the pH and the presence of alcohol deter bacteria growth. The widespread practice of washing yeast with boiled water in the homebrewing community can be traced back to Papazian's book. To the best of my knowledge, the practice appears in no professional brewing text. Professional brewers only wash their yeast when they want to kill off infection from house microflora. The solution that professional brewers use to wash yeast lowers the pH of the culture to 2.2, which is significantly lower than that of tap water. The pH of tap water is at least 7.0 in most most municipalities (most municipalities buffer their water supplies to prevent corrosion of their pipes).
All one needs to do is to leave enough liquid behind in one's primary fermentor to able to swirl the solids into suspension. As with the yeast washing process, one should wait a few minutes for the heaviest fractions of the trub and dead yeast cells to settle out after swirling before decanting the liquid into a well-cleaned and sanitized container. One should wipe the lip of the fermentor over which the "crop" will be poured with grain or 91% isopropyl alcohol before decanting the liquid (think about what a nurse or doctor does before he/she inserts a needle into one's arm).
Contrary to what most homebrewers have been led to believe, the culture needs some of the protein from the trub to remain healthy and beer is a much better environment for the culture than water, as the pH and the presence of alcohol deter bacteria growth. The widespread practice of washing yeast with boiled water in the homebrewing community can be traced back to Papazian's book. To the best of my knowledge, the practice appears in no professional brewing text. Professional brewers only wash their yeast when they want to kill off infection from house microflora. The solution that professional brewers use to wash yeast lowers the pH of the culture to 2.2, which is significantly lower than that of tap water. The pH of tap water is at least 7.0 in most most municipalities (most municipalities buffer their water supplies to prevent corrosion of their pipes).
k_mcarthur
Well-Known Member
Look up plating and slanting yeast. I only buy yeast when I need a new strain. Takes some planning, a week before brew day I take a scraping from the plate and start stepping it up. Don't have to worry about counting generations or store multiple quart jars in fridge.
WoodlandBrew
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Agreed. Skip the "yeast washing" It's just a waste of time and yeast. See here for details:
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html
http://woodlandbrew.blogspot.com/2013/01/yeast-washing-revisited.html
And if you want to isolate yeast check this out:
http://woodlandbrew.blogspot.com/2012/12/isolating-single-yeast-strain-by-plating.html
http://woodlandbrew.blogspot.com/2013/01/how-to-harvest-yeast-from-bottle.html
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html
http://woodlandbrew.blogspot.com/2013/01/yeast-washing-revisited.html
And if you want to isolate yeast check this out:
http://woodlandbrew.blogspot.com/2012/12/isolating-single-yeast-strain-by-plating.html
http://woodlandbrew.blogspot.com/2013/01/how-to-harvest-yeast-from-bottle.html
EarlyAmateurZymurgist
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+10,000
I maintained a yeast bank on agar slants for ten years before I took an eleven-year hiatus from the hobby. I am currently in the process of rebuilding my bank. I currently have six different yeast cultures in my bank, and I am in the process of adding a seventh culture (see https://www.homebrewtalk.com/f163/plating-yeast-432004/). None of my cultures are available through the U.S. homebrew trade, which is the beauty of maintaining one's own yeast bank on agar slants.
jordanmills
Well-Known Member
Rinsing, not washing.
k_mcarthur
Well-Known Member
Interested in trading slants? If so pm me.
This would seem to contradict your claim: http://woodlandbrew.blogspot.com/2013/01/abv-effects-on-yeast.html
WoodlandBrew
Well-Known Member
Im sorry,
That blog post may be a little misleading. My book is written better.
I agree with most of what EAZ is saying. There is no need to perform "homebrew yeast washing" which is better described as "yeast rincing.". I have seen that decanting the slurry can reduce the non-yeast particles and does seem to take some bacteria with it. "The Professional Brewer" mentions this technique very briefly and I could dig it up if you would like.
my experiments on alcohol effects on yeast do show degradation at high alcohol levels, but keep in mind these tests were done at ambient air temperatures. They show the effect of the alcohol on the yeast sitting at the bottom of a fermentor better than the effects in the refrigerator.
That blog post may be a little misleading. My book is written better.
I agree with most of what EAZ is saying. There is no need to perform "homebrew yeast washing" which is better described as "yeast rincing.". I have seen that decanting the slurry can reduce the non-yeast particles and does seem to take some bacteria with it. "The Professional Brewer" mentions this technique very briefly and I could dig it up if you would like.
my experiments on alcohol effects on yeast do show degradation at high alcohol levels, but keep in mind these tests were done at ambient air temperatures. They show the effect of the alcohol on the yeast sitting at the bottom of a fermentor better than the effects in the refrigerator.
But in the end wouldn't decanting beer and exchanging for boiled water increase long term viability and reduce bacteria levels? I've ditched the traditional yeast rinsing approach, but I do decant the beer once the yeast slurry compacts in the jars. I believe another of your posts mentions that bacteria levels in tap water are pretty low; I would think boiled tap water would preferable.
WoodlandBrew
Well-Known Member
Yes, I think boiled water is better than beer for storing yeast, but don't want to discount all of what EAZ said. He has some good ideas.
When I mentioned yeast washing, I was merely pointing the OP towards search terms that would turn up more results. I didn't mean to imply that it is the only (or even the best) way to save/re-use yeast.
No, really... MOST people refer to it as washing. Some people refer to washing as strictly acid washing. But MOST people equate washing with rinsing, unless specifically qualifying it with an "acid" in front. Then, it's a different thing. Take the very first link shared in this thread, for example!!
The link in my sig is not that same link, but it does highlight specific posts. For anyone interested in yeast rinsing/washing, I'd suggest to focus on wolverinebrewer's posts. His only real secret is to use an autosiphon instead of decanting. Other great ideas spread throughout that thread are to use a wedge in order to minimize the carrying over of trub.
Perhaps you could elaborate on why EVERY professional brewer who writes a book talks about yeast rinsing/washing??
And could you definitely elaborate on how you can reason that boiled water is nowhere near as sanitary as beer, which originally came from boiled water?? Also, see the graph and its source, below...
It definitely takes more than "a few" minutes. I think that 20 minutes is too short. Wolverinebrewer suggested 30. My brew partner is incredibly impatient, so we always went with around 25 minutes.
Not bad. But, ideally... one should use an autosiphon instead of increasing the chances of transferring the trub, which you DON'T want.
Perhaps you could explain this, then?
http://woodlandbrew.blogspot.com/2013/01/abv-effects-on-yeast.html
And if you use a sanitized autosiphon, as is done with every other racking step in the brewing process, what is the chance of taking bacteria along with your yeasty water??
I have seen no evidence to the contrary.
How long after you begin refrigeration do you decant the liquid beer once the yeast slurry has compacted??
I do believe that the answer to this question certainly affects the integrity of the yeast for future generations. But EAZ has made excellent posts elsewhere about wanting to toss off the least flocculent yeast, because that is the yeast most likely to mutate into a respiratory-deficient mutant (aka: "petites")... however, I have neither seen, nor heard any verified evidence of this happening on the homebrew scale. EAZ mentions that breweries do indeed get rid of the bottom and top layers of trub in their conicals... but perhaps that is only for mid-range flocculent yeasts? My thinking is that they do it that way because that is the nature of preserving yeast integrity when using a conical in a mass-brewing fashion. On the homebrew scale, neither saving yeast cakes, nor rinsing/washing yeast in mason jars allows you to choose the middle of the pack. So if you keep the bottom and middle, while getting rid of ONLY the highly flocculent yeast, the future yeast generations will NOT perform well [or at least not as expected] in future fermentations. My theory is that if you really want to decant that beer, you need to let it settle for 3-7 days until the beer is actually clear. Yeast rinsing/washing can allow you to pitch the entire mason jar (it's just boiled water, which you just put in your wort!!) immediately without ditching the least flocculant yeasties, which I'm really thinking that you'll want to keep around.
Would prefer some real evidence one way or another, tho, because this is just my theory and haven't really given much thought on the importance of these least flocculant yeasties until the past week or so.
jordanmills
Well-Known Member
That may be how they refer to it, but that doesn't mean that's what they're doing.
Language is not created by one man.
Language means whatever the community wants it to mean. I see it referred to as washing over rinsing by a ratio of 4:1, so when someone mentions washing I know what they mean. If they say acid washing, I also know what they mean.
Context is key.
jordanmills
Well-Known Member
That's not an excuse to promote ignorance, especially in a group so generally receptive of learning.
It isn't promoting ignorance. It is making an effort (and a small one at that) to understand what people are trying to communicate.
There is nothing magical about the term "wash" that inherently makes it mean something other than what people most often mean when they say they washed their yeast.
EarlyAmateurZymurgist
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Beer has a lower pH than water. It also has alcohol. Both of these attributes make beer far less hospitable to bacteria growth than boiled water. Most public water supplies are buffered into the alkaline range to prevent pipe corrosion. While boiling can precipitate the buffering agent, one is left with a liquid with a pH of at least 7.0.
Boiled water is also not absolutely sterile, which makes rinsing yeast with boiled water a poor brewery practice. The only absolutely sterile water is autoclaved water.
RCCOLA
Well-Known Member
This makes a lot of sense to me. Here's why:
I was prepping for my last brewday and checked my pH buffer solution. The pH 7 buffer was discolored and looked as if something was floating in it. It had a big blob of mold or bacteria in it. It had been mixed from a powdered capsule and a freshly opened bottle of distilled water in a new specimen bottle and kept covered when a sample wasn't being poured into my pH meter cap. The pH 4(acidic solution) was fine. Low pH protected it from bacterial growth.
I harvested some yeast a couple months ago and put it in a sanitized Mason jar. Very clean slurry. After it settled, I decanted it and poured boiled and cooled water on top of it. I had to off-gas the jar every 5 days or so, sometimes it had quite a bit of pressure built up in the jar, stored at ~38F.
Something was deteriorating (or growing)in that jar to produce the gas.
Makes me wonder if water with pH lowered to ~4.0 with phosphoric acid would be a good medium to cap the yeast slurry with.
See post #16 of this thread...
Are you able to explain the yeast viability decreasing with more alcohol present over time.... much, much faster than boiled water present??
http://woodlandbrew.blogspot.com/2013/01/abv-effects-on-yeast.html
Day 70 of saved yeast with pure water = 86% viability
Day 70 of saved yeast with 5% ABV = 44% viability
Day 70 of saved yeast with 6% ABV = 28% viability
Day 70 of saved yeast with 7% ABV = 15% viability
Day 70 of saved yeast with 9% ABV = 1% viability
Nobody's arguing that boiling isn't absolutely sterile, but it is pretty much the BEST option available, which is why homebrewers boil their water before adding their sugars and hops. Releasing hop proteins is best done at around 180-190 degrees, and I'd imagine those are ideal temps for releasing sugars from grains, too, but I've only done extract brews so far. But if autoclaving were necessary, then we would hear about it more often. The typical sanitation process works for most people. Boil water. Boil jars. Sanitize all other equipment that could potentially come even remotely close to touching the wort/beer. People who do this will rarely ever have a problem.
The reason to boil water is to remove the oxygen and put the yeast to sleep, ASAP. It works. There's absolutely NOTHING to worry about, other than spores, which I'd imagine is a very low possibility of making it into anyone's rinsed/washed yeast. The original yeast washing thread is very long, and I don't remember any empirical examples of infections, even from spores. Maybe there was one, but I doubt it was due to boiling the water and jars. Plenty of people just boil the water and sanitize the jars. No problems.
I really wish I had a copy of Yeast in front of me again so I could review why it is suggested in the book to wash/rinse yeast. Surely, all the professionals who write these books don't just mention yeast washing because it's an outdated technique.
Are you able to explain the yeast viability decreasing with more alcohol present over time.... much, much faster than boiled water present??
http://woodlandbrew.blogspot.com/2013/01/abv-effects-on-yeast.html
Day 70 of saved yeast with pure water = 86% viability
Day 70 of saved yeast with 5% ABV = 44% viability
Day 70 of saved yeast with 6% ABV = 28% viability
Day 70 of saved yeast with 7% ABV = 15% viability
Day 70 of saved yeast with 9% ABV = 1% viability
Nobody's arguing that boiling isn't absolutely sterile, but it is pretty much the BEST option available, which is why homebrewers boil their water before adding their sugars and hops. Releasing hop proteins is best done at around 180-190 degrees, and I'd imagine those are ideal temps for releasing sugars from grains, too, but I've only done extract brews so far. But if autoclaving were necessary, then we would hear about it more often. The typical sanitation process works for most people. Boil water. Boil jars. Sanitize all other equipment that could potentially come even remotely close to touching the wort/beer. People who do this will rarely ever have a problem.
The reason to boil water is to remove the oxygen and put the yeast to sleep, ASAP. It works. There's absolutely NOTHING to worry about, other than spores, which I'd imagine is a very low possibility of making it into anyone's rinsed/washed yeast. The original yeast washing thread is very long, and I don't remember any empirical examples of infections, even from spores. Maybe there was one, but I doubt it was due to boiling the water and jars. Plenty of people just boil the water and sanitize the jars. No problems.
I really wish I had a copy of Yeast in front of me again so I could review why it is suggested in the book to wash/rinse yeast. Surely, all the professionals who write these books don't just mention yeast washing because it's an outdated technique.
By "freshly opened bottle of distilled water", I assume you mean you DIDN'T boil the water??
I do think that EAZ has a point that any "yeast" that doesn't fall to the bottom within a day after being refrigerated in boiled water [with no oxygen], very likely isn't any yeast that you want to keep around, and is in fact, a "respiratory deficient mutant" (i.e. - "petities").
But for long term storage, boiled water trumps beer, and that's why it's recommended in every homebrewin book out there.
RCCOLA
Well-Known Member
I did not. And neither did I boil it in the pH 4.0 solution. The 7.0 grew something, the 4.0 did not. Both had anti-mold drops added to them.
Did you read what I proposed? Water with pH lowered to pH 4.0.
EarlyAmateurZymurgist
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The alcohol is also keeping bacteria and mold at bay. Decreased viability is better than an infected culture. Yeast cells are going to lose viability no matter what one does under home brewery conditions. The name of the game is to keep the culture as clean as possible. Storing the culture under fermented beer versus boiled water accomplishes that task.
By the way, your laser like focus on maintaining viability is causing you to ignore critical data that the author included in his blog posting:
"The top two sets of data, for 0% ABV and 4% ABV show very little drop in viability over time, but notice at about day ten there seems to be significant drop. This corresponds to the time I also started noticing mold cells growing with the yeast. Unfortunately, daily measurements created dozens of opportunity for contamination."
This data supports my thesis. It is more important to keep a culture clean than it is to maximize viable cell count at the cost of contamination. The opportunity for infection was present when all samples were taken. Yet, only the low alcohol samples became infected with mold. Low alcohol beer also tends to be less acidic beer because low alcohol beer tends to be lightly hopped. Hops lower the pH of beer, which, in turn, makes it tougher for unwanted microflora to gain a foothold. Brewers yeast strains have been domesticated to survive under the hostile conditions imposed by beer.
Minimizing the introduction of bacteria is of course going to accomplish the task of minimizing the introduction of bacteria. Absolutely no argument there.
But my laser like focus is not on the contamination present in boiled water.
My focus is on that last line that you didn't bold --> "Unfortunately, daily measurements created dozens of opportunity for contamination."
THAT is the name of the game.
And SOMETIMES, the name of the game is viability of yeast cells. My buddy and I bottle harvested some Pacman yeast just over 14 months ago, and I'm hoping that because we used boiled water, the yeast viability will not have dropped as fast as if we had left it refrigerated with alcohol. We just made our starter yesterday, so only time will tell, but I think we'll be OK.
The data, outside of the graph, does NOT support your thesis. I really don't understand how the graph says what it says, when the table says what IT says. The wording of that sentence -- "The top two sets of data, for 0% ABV and 4% ABV show very little drop in viability over time, but notice at about day ten there seems to be significant drop." -- could perhaps be referring mostly to the 4% ABV reference numbers?? Only Woodland would be able to explain the disconnect between the graph and the table, IMHO.
Here are two comments of his from this very thread....
I've mentioned this before, but the whole bit about "decanting" the yeast is NOT the optimal way to rinse yeast.
"I have seen that decanting the slurry can reduce the non-yeast particles and does seem to take some bacteria with it."
I'm really not quite sure if that sentence says what it was intended to say... in regards to reducing the non-yeast particles, because saving a yeast cake "can reduce the non-yeast particles", as well. But neither method should take any bacteria with it, provided that you are using a sanitized autosiphon. This is something that he doesn't do on his blog, and that's why he consistently got trub in his yeast, instead of the 100% yeast he should have gotten by not disturbing the trub at all with the autosiphon. You use it with all steps, why not for yeast washing?
Well, I'm not saying that an acidic medium isn't better than a non-boiled medium. What I'm saying is that a boiled medium is just as good as, if not better than, the acidic medium.... particularly in regards to long-term yeast viability.
Also, what did you cover the sample with? Was it sanitized, sterilized?
The only thing that would be fair in this discussion is that you actually use boiled water in your experiment, because NOBODY in the yeast washing thread is forgoing that process.
Rinsing/Washing Yeast
===
PROS:
- Long-term yeast viability, particularly past one month or so.
- Ability to remove ALL prior beer flavors, trub, dead yeast from the prior recipe [particularly useful when making a new recipe].
- Better estimates as to yeast count for next pitch.
CONS:
- Virtually non-existant possibility of adding contamination (because you'll be sanitizing your autosiphon & sterilizing the water and jars).
- A matter of adding a couple extra minutes of actual work to your process, along with waiting time (hour for water to boil and cool, 30 min. for trub to settle, few hours to a day for yeast to settle; however, pitching yeast cake should preferably also wait few hours to a day for yeast to settle and pitch the top liquid with potentially respiratory deficiant mutants (i.e. - "petites")).
===
PROS:
- Long-term yeast viability, particularly past one month or so.
- Ability to remove ALL prior beer flavors, trub, dead yeast from the prior recipe [particularly useful when making a new recipe].
- Better estimates as to yeast count for next pitch.
CONS:
- Virtually non-existant possibility of adding contamination (because you'll be sanitizing your autosiphon & sterilizing the water and jars).
- A matter of adding a couple extra minutes of actual work to your process, along with waiting time (hour for water to boil and cool, 30 min. for trub to settle, few hours to a day for yeast to settle; however, pitching yeast cake should preferably also wait few hours to a day for yeast to settle and pitch the top liquid with potentially respiratory deficiant mutants (i.e. - "petites")).
