The cold hard truth about rinsing yeast with boiled water

[EarlyAmateurZymurgist]

This highlights the importance of adding a cryoprotectant to frozen stocks. Deep freezing also suspends metabolic activity of the yeast and any contaminating organisms. In those conditions, bacteria are not growing while the yeast are dormant, the cold affects the entire sample.

There is definite merit in freezing, but I am not convinced that freezing in an consumer-level deep freezer provides any significant long-term advantage over slants. Now, if we are talking about about a freezer that is capable of -80C or lower temperatures, then freezing is the only way to go.

You mentioned the benefit of using 50ml stocks. Are your frozen stocks mostly composed of yeast cells? Or are they 50ml liquid cultures?

 

[Orthobrewsky]

Do you mean something like this? https://www.homebrewtalk.com/f163/c...t-boiled-water-451925/index3.html#post5806534

I admit it's not much, but the best I can do with the equipment I have.

About that post I referenced--I didn't get any comments from EAZ, but I'd be interested in his thoughts. I did what is so often described by homebrewers, specifically a single rinse. I add around a quart of water to about a quart of yeast cake/beer. I like to drink as much of my beer as I can, so I tilted and left very little above the cake when i siphoned. The beer was diluted to around 50% concentration, making it like a very low gravity beer. Based on western civilization being made possible through most everyone drinking very weak beer in lieu of contaminated water, I think the alcohol level should still be toxic or at least inhibitory to most bacteria.

The pH rose a bit, but wasn't so bad and my water is pretty middle of the road on alkalinity, so I think my results are probably pretty average for folks doing a single rinse. Thus, I think most people are keeping the "force field" mostly intact. I wonder if my results cause EAZ to be any less worried about the typical yeast rinser.

It would not be difficult or expensive for folks to rinse with low alkaline water, so that the pH would change little. Otherwise, a drop or two of acid might be a nice precaution. However, I think that if people follow the typical recommendation of trying to reuse yeast within a few days and not go longer than two weeks, there would probably be very little difference in outcomes between these methods.

 

[Bottoms_Up]

But what I haven't seen answered is how to store harvested slurry for several months without agar slants and freezing? Many people have used rinsed yeast successfully up to a year later. But everything I've read says to not use the harvested yeast slurry after 2-4 weeks. I don't brew enough to do that. How can I make my slurry last longer without agar slants and freezing (which I may look at in the future)?

I generally only brew 10 gallons every 3 or 4 months. During that time, I keep the yeast slurry in the fridge, but do a "yeast starter" on it every 6 weeks or so with DME and yeast nutrient to help keep its viability (I use a stir plate and a 2 liter Erlenmeyer flask). Since some have kept yeast alive without doing a starter for many months, I figure that repeating a yeast starter no more than about 6 weeks is more than adequate to keep it quite viable. Also, I calculated the yeast viability, and using 6 weeks seems to be a good compromise, since I do another yeast starter a few days before brewing in any case. Thus I assume that you could keep yeast quite viable for well over a year if you repeat a yeast starter no longer than about every 6 weeks during that time.

I have been using the same lager yeast in this way for well over a year with no noticeable detrimental effects so far. I have been rinsing with some boiled and cooled water, but based on the discussion in this thread, I will change to storing the yeast under beer. In addition, I think it wise to take extra effort to remove as much trub as possible before transferring to the fermenter. Personally, I get very little trub when recovering the yeast. In this way, there's little worry about saving almost all the yeast slurry (I only discard a very small amount from the bottom of the slurry, where the heavier trub, etc. has fallen). Also, I usually pour the slurry into Mason jars after the slurry has settled for no more than about 1 or 2 minutes. This is because I save lager yeast, which settles very rapidly (based on my experience, and the experience of a few others, most ale yeasts seem to stay in suspension for at least 20 or 30 minutes, while lager yeasts generally settle within minutes, and usually before the trub settles - thus, in terms of layers, the white milky layer is at the bottom, the trub layer is above that, and the beer layer is above that).

 

[tagz]

About that post I referenced--I didn't get any comments from EAZ, but I'd be interested in his thoughts. I did what is so often described by homebrewers, specifically a single rinse. I add around a quart of water to about a quart of yeast cake/beer. I like to drink as much of my beer as I can, so I tilted and left very little above the cake when i siphoned. The beer was diluted to around 50% concentration, making it like a very low gravity beer. Based on western civilization being made possible through most everyone drinking very weak beer in lieu of contaminated water, I think the alcohol level should still be toxic or at least inhibitory to most bacteria.

The pH rose a bit, but wasn't so bad and my water is pretty middle of the road on alkalinity, so I think my results are probably pretty average for folks doing a single rinse. Thus, I think most people are keeping the "force field" mostly intact. I wonder if my results cause EAZ to be any less worried about the typical yeast rinser.

It would not be difficult or expensive for folks to rinse with low alkaline water, so that the pH would change little. Otherwise, a drop or two of acid might be a nice precaution. However, I think that if people follow the typical recommendation of trying to reuse yeast within a few days and not go longer than two weeks, there would probably be very little difference in outcomes between these methods.

The procedure you referenced seems like a solid way to go. You are reducing the alcohol to more desirable levels and keeping the pH on the lower end of the spectrum. If you were using boiled RO water, all the better. I'm no scientist but that seems to meet the criteria for safe storage on the homebrew scale. It's what I typically do.

 

[mtnagel]

I generally only brew 10 gallons every 3 or 4 months. During that time, I keep the yeast slurry in the fridge, but do a "yeast starter" on it every 6 weeks or so with DME and yeast nutrient to help keep its viability (I use a stir plate and a 2 liter Erlenmeyer flask). Since some have kept yeast alive without doing a starter for many months, I figure that repeating a yeast starter no more than about 6 weeks is more than adequate to keep it quite viable. Also, I calculated the yeast viability, and using 6 weeks seems to be a good compromise, since I do another yeast starter a few days before brewing in any case. Thus I assume that you could keep yeast quite viable for well over a year if you repeat a yeast starter no longer than about every 6 weeks during that time.

I have been using the same lager yeast in this way for well over a year with no noticeable detrimental effects so far. I have been rinsing with some boiled and cooled water, but based on the discussion in this thread, I will change to storing the yeast under beer. In addition, I think it wise to take extra effort to remove as much trub as possible before transferring to the fermenter. Personally, I get very little trub when recovering the yeast. In this way, there's little worry about saving almost all the yeast slurry (I only discard a very small amount from the bottom of the slurry, where the heavier trub, etc. has fallen). Also, I usually pour the slurry into Mason jars after the slurry has settled for no more than about 1 or 2 minutes. This is because I save lager yeast, which settles very rapidly (based on my experience, and the experience of a few others, most ale yeasts seem to stay in suspension for at least 20 or 30 minutes, while lager yeasts generally settle within minutes, and usually before the trub settles - thus, in terms of layers, the white milky layer is at the bottom, the trub layer is above that, and the beer layer is above that).

Yeah, that's what I was thinking too, but EAZ said it wasn't that great either:

I am sorry for not answering your question. I planned to get to it, but thread kept scrolling.

Keeping a liquid culture alive without periodically repitching it is not a viable long-term storage strategy. You can periodically feed the culture by decanting the green beer and adding fresh bitter wort, but that's like putting a band-aid on a sucking chest wound. It may work for a while, but you will eventually have to replace the culture.

But maybe it's good enough.

 

[dlester]

Nice write-up about yeast and washing. I agree that boiling doesn't get it all, but never put together that washing the yeast may actually be inserting wild yeast. Hmm, thanks for that. I have heard that washing yeast can kill them, and therefore avoided it. Not sure I care whether that statement is true or not, but I typically avoided washing yeast by removing all trub after the boil and using a conical fermenter to collect yeast.

I first whirl pool the wort at flameout in the boiler. After 20-30 minutes of settling, I push the wort to my liquor tank and do a second whirlpool using my pumps. The first whirl pool in the boiler is good, but is not wide enough to push all the trub to the middle of the boiler. It sounds like over-kill, I know. However, it really isn't that much more work and my wort transfers to the fermenter perfectly clear. Since I use a conical fermenter, I let out and throw away a small amount of what first comes out followed by storing the rest that follows.

Thanks again for the article,
Cheers

 

[tagz]

Nice write-up about yeast and washing. I agree that boiling doesn't get it all, but never put together that washing the yeast may actually be inserting wild yeast.

Boiled water shouldn't introduce wild yeast, as yeast can't survive 212F. He's saying there are some spores that can survive, but it questionable if those same spores can survive once hops and alcohol are introduced.

The larger point is keeping the slurry at a lower pH and under a layer of low ABV liquid to stop bacteria from growing.

 

[Warthaug]

I am late to the game, but as someone who is both a microbiology prof and whom maintains yeast for both research and brewing purposes, I have a bit I would like to add to the discussion.

1. Firstly, in response to the OP's point about spores, he is partially correct - some (not all) spores can survive boiling. However, their impact on washed yeast is going to be minimal. Spores are not metabolically active, and if washed properly, the resulting environment will be nutrient depleted. This means the spores will not germinate - and if they do they will be unable to grow to any significant degree. Of course, lysed yeast make great food, but if that is occurring at a level that supports germination of bacterial spores you have much more serious issues than a small number of spores in your washing water.
   
2. I'd also like to address the OP's point about sterilized water. While we do use autoclaved water in the lab, it is considered sterile only until you open the bottle (air is chalk-full of bacteria & molds). Meaning, when we work with cultures in the lab (which is not done in biocontainment hoods unless the organism is a biohazard level 2+ or higher organism, or there is a need for absolute cleanliness) we are working with (at least in theoretical terms) contaminated water. And we don't generate fresh water ever time - bottles will sit, and be repeatedly used, over periods of several weeks. And yes, if you try you will be able to pull culturable organisms out of bottles of autoclaved, but opened water. So the comparison is not one of sterile vs non-sterile water; rather he comparison is one of water with differing (but in both cases, very minute) degrees of contamination.
   
3. Thirdly, I'd like to address the repeat discussion of centrifuged yeast. In practical terms there is no great difference between centrifuged yeasts and yeast which has settled. In theory you can get a better separation of yeast from material that is more or less dense in a centrifuge, but in reality to achieve any meaningful stratification of yeast versus other suspended particles requires solutions of much higher density than provided by water or wort. For water/wort suspended organisms/trub, all centrifugation does is condense the settling time from hours/days to a few minutes. The ability to the separate the yeast & other settled materials from the supernatant is effectively equal in both systems (unless you add stuff to greatly increase the density of the media - something we do in the lab, but something not normally done in breweries).
   
4. Fourthly I'd like to comment on much of what has been written about the costs/benefits of storing under fermented wort vs. water. While fermented wort does provide modest acidity and alcohol to act as a preservative, it also provide a medium which can be consumed by many organisms. Ethanol, dextrins, hop compounds, etc, all represent metabolizable substrates that many organisms can consume. As anyone whose done some sour brewing using organisms in the secondary knows, there are a lot of beasties out there who love to live in pre-fermented wort. In other words, fermented wort provides some protection from some organisms, while simultaneously providing a nutrient-rich environment for others. Adding ethanol or acid to water produces a similar effect. And don't forget, that acid and alcohol is stressful to the yeast,even in low-alcohol beers. Alcohol especially, and to a lesser extent acids, are waste products; their presence negatively impacts metabolic pathways, even in relatively low concentrations. Just because they are not at acutely toxic doses does not mean that they are not negatively impacting the yeasts.
   
   In contrast, water doesn't provide the acidity (although this could easily be added by the addition of a buffer) or alcohol, so it is less preservative against ethanol/acid susceptible organisms. But it is also devoid of nutrients, meaning it will not support the growth of organisms. In other words, with water vs. fermented wort you're dealing with 6 of one and a half dozen of the other - wort protects against some infections while supporting the growth of others; water provides no protection, but also doesn't support growth. IMO water has a slight edge in that you also rid the culture of metabolic end-products (ethanol, esters, etc) that can stress yeast. But that advantage comes with a bit of risk - any time you open your stored yeast you risk contamination from organisms in the air and in/on any equipment and materials you are using.
   
5. One last thing and then I'll stop whining. Contrary to what many have written here, water is extensively used in microbiology as a washing and storage medium. Any time we want to strip away metabolic products, remove selective media components, cleanly swap organisms between different type of growth medium, etc, our default method is washing - e.g. we pellet (centrifuge) the organism, decant the old media, resuspend the organism in water, re-pellet, and lastly resuspend in new media (sometimes we repeat the water-wash 3 or more times if high cleanliness is required). Likewise, short-term storage is also often in water. Because water does not support the growth of organisms, and is not harmful to (most of) the organisms we are studying, its a great way to temporarily store a culture in a metabolically inactive state.

When you get down to it, this discussion of yeast washing is somewhat off target. As I mentioned above, both storage under beer and storage under water have their advantages and disadvantages. If you can keep things clean, washing can reduce your risk of contamination through depleting the storage medium (e.g. fermented wort) of nutrients which can be consumed by contaminants, and can reduce stress on the yeast by ridding the medium of metabolic waste products like ethanol. However, if you are not clean you risk contamination from environmental sources - and boiled water is not the concern; there will be far more viable organisms floating around in the dust in the air, or on the surface of a poorly cleaned funner/container, then viable spores will be remaining in some boiled tap water.


Bryan

 

[harrke]

Your profile states that you work in reactor operations. Are you a former Navy "Nuke?"

Yes. Submarine Officer in Groton and Ballston Spa.

 

[tagz]

Thank you Wathaug. That post makes the thread worth it.

 

[pelipen]

Thank you Wathaug. That post makes the thread worth it.

Seconded. That was the practical example I was waiting for after reading every page.

 

[Bottoms_Up]

Yeah, that's what I was thinking too, but EAZ said it wasn't that great either:

But maybe it's good enough.

"Not that great"??. I have tested it in practice and can guarantee that, at least in how I did it, it works quite well for upwards of one year. That's 40 gallons of premium lager in just over one year so far, using only one single package of Wyeast (or eight 5-gallon batches rather than one) - without any off-tastes. To me, that's already more than "great". In addition, I plan to make at least another 10-20 gallons of lager before I decide to use a fresh new package of yeast. So one single package of liquid yeast will hopefully be good for at least twelve five-gallon batches of lager, rather than just one batch. To me, despite EAZ's negativity, that's far more than "great".

 

[EarlyAmateurZymurgist]

Warthaug:

I was out on your blog. I am just curious, but why do you keep cultures that can be obtained easily through the home brew trade in your bank? I do not have access to an -80C freezer; therefore, periodic subculturing is a fact of life for me. I used to maintain a bank that was just shy of forty cultures. It was a hobby unto itself. Now, I only bank brewery and culture collection cultures (at $100.00+ each, it pays to bank culture collection cultures).

With that said, I have an interesting culture in my bank that I may be willing to trade, it's CBS 1171 (a.k.a NCYC 505, ATCC 18824, NRRL Y-12632). This stain was isolated at the Orangeboom Brewery in February of 1925 by A.C. van Wijk. CBS 1171 is a well-studied yeast strain.

 

[EarlyAmateurZymurgist]

"Not that great"??. I have tested it in practice and can guarantee that, at least in how I did it, it works quite well for upwards of one year. That's 40 gallons of premium lager in just over one year so far, using only one single package of Wyeast (or eight 5-gallon batches rather than one) - without any off-tastes. To me, that's already more than "great". In addition, I plan to make at least another 10-20 gallons of lager before I decide to use a fresh new package of yeast. So one single package of liquid yeast will hopefully be good for at least twelve five-gallon batches of lager, rather than just one batch. To me, despite EAZ's negativity, that's far more than "great".

Here's what I wrote:

Keeping a liquid culture alive without periodically repitching it is not a viable long-term storage strategy. You can periodically feed the culture by decanting the green beer and adding fresh bitter wort, but that's like putting a band-aid on a sucking chest wound. It may work for a while, but you will eventually have to replace the culture.

You are doing the former, not the latter. The latter is basically replacing the supernatant with an equal amount of bitter wort and placing the culture back in the refrigerator. You are effectively cropping a new culture every six weeks.

 

[Bottoms_Up]

You are doing the former, not the latter. The latter is basically replacing the supernatant with an equal amount of bitter wort and placing the culture back in the refrigerator. You are effectively cropping a new culture every six weeks.

I have re-read what you wrote and now see that we are on the same page. I was a little confused by the terminology "repitching", but now see that we both mean the same process as periodically making a new yeast "starter" with the yeast (including adding yeast nutrient, which is important, since I understand that yeast needs nutrients even while "hibernating"). It's odd how few mention this simple process of keeping the yeast quite active (viable) over long periods of time. Also, with this procedure, the previous "beer" layer becomes replaced with fresh wort (made from boiled water plus DMA + yeast nutrient), thereby removing much of the bacteria that may have been in the previous liquid. Obviously, there may still may be some bacteria in the boiled wort, as well as in the yeast cake, but overall, I would expect that there should be some reduction of bacteria every time that a new "starter" is made during the storage period.

 

[GRBC]

EAZ, I appreciate your contribution here. After all, nothing dies a slower death than "common knowledge" on HBT. Witness the raging resistance to the concept of dropping a secondary fermentation. Also, even the "experts" evolve and grow as their understanding evolves. Like John Palmers beer color to Residual alkalinity nomograph approach from how to brew. So don't let the bastards get you down.

One question that I have is the difference between he state of dormancy that we water based yeast rinsers presume and the state of starvation that you propsose. Is yeast under green beer in the fridge in a state of dormancy, or is it not dormant, but not starved of nutrients?

 

[GRBC]

Also, if I could summarize my understanding of your key points, it would be the following. Would you mind letting me know if I have it right?

1. Harvesting yeast from the fermenter with beer is easier than adding autoclaved (or boiled) rinse water.
2. Using the fermented beer from the FV instead of adding rinse water eliminates an additional potential source of infection from mold, bacteria, wild yeast, etc. that may be introduced in the water itself or from the air in the act of adding the rinse water (the vector!)
3. Using either the fermented beer or new rinse water presents some opportunity for the introduction of the bad stuff in the act of transferring from the FV to the container that will hold the yeast slurry, but the pH and alcohol level of the beer make it less likely for these to reproduce and grow in the slurry medium.
4. Yeast slurry maintained at 34-38F under beer will remain more viable, longer than the same yeast under sterile water. This is because the beer has nutrients that will feed the yeast, and water starves them leading to yeast cell death.

 

[jakenbacon]

If i didn't ask, i don't know, 5 times for am answer from you that would be one thing. If you didn't directly respond to me twice after i asked the question and still be unable to answer said question, well that's a different matter. Just say you don't know.

I got all my vaccines, you can't go to college if you don't have them. I don't think I got MMR though, if I did, I didn't pass my titer test 6 years ago to get operating room access privileges. I've risked my life many times, as I'm sure everyone else has. I'm not so uptight that I'm afraid to risk a little 5 gallon batch of beer. Our a pint of yeast.

But, if you're the expert on thus, why haven't you performed said experiment yet? I think the onus I'd on you to do that. Maybe you should've done that before debating in such a know it all manner, speaking as if you have facts and are dealing with certainties.

Oh and, I don't think anyone is attacking you, it's a debate. You brought it on yourself. If you're going to argue against the way people have been doing something for so long, the burden of proof is on you.

Note: on phone working, sorry if spellcheck got me.

Lol keep reachin cervid. Maybe people will start to think you have a legitimate argument.... O wait no they won't.... EZAZ obviously knows much more than you on the topic and you are just drowning the thread with your what if this, what if that crap. If you want to banter go to the debate forum. And most of all, RDWAHAHB.

:cross:

 

[cervid]

You're right jerkinbacon. I'm the only one countering is argument that the way people have been washing yeast at home for a decade is now all of a sudden inadequate. I'm the only one asking 'what if this, what if that'. I'd argue that most of the people around here are washing their yeast and think he's a bit alarmist. If not, why so much debate and why is the yeast washing illustrated still stickied and not his technique?

He does know much more about yeast than I do, I'm not debating that. But, I know enough to know when someone is spewing opinion and really doesn't have a hell of a lot of evidence behind what they say. What he's saying is just that, opinion. If you are going to argue a point and counterpoint without any real evidence, then that by definition is a debate. Considering washing has been done for so long, and there are plenty of people who know more than he does out there saying to do it, then what did you expect?

How many books has he written on the subject? Maybe even just a pseudo white paper with experiments on the internet? It doesn't even have to be peer reviewed.

But, the whole point of this is to do exactly that, RDWHAHB. Wash your yeast or not, who gives a ****? I'm not the one playing chicken little about whether or not you wash your yeast. The OP should take that advice as well, and this whole post should've been in the debate section, considering the nature of it.

But hey, thanks for playing jerkin. Nothing like trying to jump into a post 22 pages in with nothing constructive to say, just to try to talk some **** and really add nothing to the discussion.

Don't you have to pay for the debate section?

 

[EarlyAmateurZymurgist]

One question that I have is the difference between he state of dormancy that we water based yeast rinsers presume and the state of starvation that you propsose. Is yeast under green beer in the fridge in a state of dormancy, or is it not dormant, but not starved of nutrients?

No, it too is dying a slow death.

 

[masonsjax]

...and cue the name calling.

 

[GRBC]

See what I did there...

You're right kevinbacon. I'm the only one countering is argument that the way people have been racking to secondary at home for a decade is now all of a sudden inadequate. I'm the only one asking 'what if this, what if that'. I'd argue that most of the people around here are using a secondary and think he's a bit alarmist. If not, why so much debate and why is the secondary racking still stickied and not his technique?



He does know much more about fermentation than I do, I'm not debating that. But, I know enough to know when someone is spewing opinion and really doesn't have a hell of a lot of evidence behind what they say. What he's saying is just that, opinion. If you are going to argue a point and counterpoint without any real evidence, then that by definition is a debate. Considering racking to a secondary has been done for so long, and there are plenty of people who know more than he does out there saying to do it, then what did you expect?



How many books has he written on the subject? Maybe even just a pseudo white paper with experiments on the internet? It doesn't even have to be peer reviewed.



But, the whole point of this is to do exactly that, RDWHAHB. Rack your beer or not, who gives a ****? I'm not the one playing chicken little about whether or not you use a secondary. The OP should take that advice as well, and this whole post should've been in the debate section, considering the nature of it.



But hey, thanks for playing kevin. Nothing like trying to jump into a post 22 pages in with nothing constructive to say, just to try to talk some **** and really add nothing to the discussion.



Don't you have to pay for the debate section?

 

[GRBC]

I should say that what I'm interested in is the truth. Don't really care if the way I've always done it is right or wrong. I appreciate anyone who challenges the status quo even if all it eventually does is confirm the way we have always done it. However, without people being open to the possibilities of finding a better way, the home brewing hobby would be so limited - like it used to be!

 

[cervid]

...and cue the name calling.

Doesn't it seem like posts on this forum always go downhill? I wonder if this is a product of how for the last ten years we give our kids ribbons and awards for 10-15th place. People are too coddled, no one can take debate for what it is. It's always taken personally.

I'll bet them to it.. I'm an ******* because I have the nerve to question that yeast washing might not be that bad. I'm too confrontational for even posting a comment that isn't in agreement or isn't PC, I guess I need to be more passive. I mean after all, this forum asterisks out the word ****.. Oh and, I must be a dullard because I'm not a zymurgist, because we all know zymurgy is the pinnacle of intellectualism.

People need to lighten up.

 

[Bottoms_Up]

I, for one, have thoroughly enjoyed the discussion, and have learned much. I think most have been quite civil under the circumstances, although there were times when some seemed to try to provoke personal attacks. At other times, there were misunderstandings, and it was good to see those people admit their misunderstanding and aim for clarification.

One of the advantages of a good discussion or debate, is to identify the pros and cons of a process. I think that has been done quite well, and it might be useful at this point to summarize all those. Also, most discussions end up stating opinions, since at that point, the opinions have not yet had a chance to be properly tested. I think that this would now be an opportune time to test out those opinions with some objective tests, as some have already suggested. I, myself would be willing to do this, but unfortunately, I do not have the proper facilities or equipment, or necessary knowledge about bacteria and wild yeasts.

Hopefully, someone more knowledgeable, and with access to the proper facilities, might be willing to pursue this further, and provide feedback at a future time. This would be of great advantage to the entire homebrewing community and help us improve our results.

 

[boydster]

Dude you drove this thread downhill with reckless abandon.

 

[cervid]

I should say that what in interested in is the truth. Don't really care if the way I've always done it is right or wrong. I appreciate anyone who challenges the status quo even if all it eventually does is confirm the way we have always done it. However, without people being open to the possibilities of finding a better way, the home brewing hobby would be so limited - like it used to be!

+1, and I believe I've said two or three times throughout this post, I'm going to be doing it his way for a while. His points were enough to make me not spend extra time and effort with washing. I understand his logic and points, I just don't know that for the people who want to wash their yeast are doing anything wrong either..

Washing is a pita and is the whole reason I got a 5L flask and stirrer anyway.. So, I can harvest from that and dump the stuff from my fermenter down the drain. It's good for my septic tank.

 

[GRBC]

+1, and I believe I've said two or three times throughout this post, I'm going to be doing it his way for a while. His points were enough to make me not spend extra time and effort with washing. I understand his logic and points, I just don't know that for the people who want to wash their yeast are doing anything wrong either..



Washing is a pita and is the whole reason I got a 5L flask and stirrer anyway.. So, I can harvest from that and dump the stuff from my fermenter down the drain. It's good for my septic tank.

Right on. Like most things in homebrewing, there is no right or wrong. Does it work for you? Does your beer taste good? Do you enjoy doing it? Does it harm anyone else? Great!

I can report that I have made homebrew that I really liked using yeast slurry rinsed and stored with boiled water, and from slurry decanted and stored under its fermented beer. I have also used a secondary fermenter a few times, but mostly don't bother anymore, and generally rehydrate dry yeast - but not always! I usually aerate with pure O2, but sometimes I just shake the carboy all little instead. Go figure...

Still, I enjoy learning about the reported pros and cons of the process through threads like this and through experience at home. Cheers.

 

[eastoak]

Doesn't it seem like posts on this forum always go downhill? I wonder if this is a product of how for the last ten years we give our kids ribbons and awards for 10-15th place. People are too coddled, no one can take debate for what it is. It's always taken personally.

I'll bet them to it.. I'm an ******* because I have the nerve to question that yeast washing might not be that bad. I'm too confrontational for even posting a comment that isn't in agreement or isn't PC, I guess I need to be more passive. I mean after all, this forum asterisks out the word ****.. Oh and, I must be a dullard because I'm not a zymurgist, because we all know zymurgy is the pinnacle of intellectualism.

People need to lighten up.

anyone reads through your posts on this thread would agree that you have a very strong desire to be right. this is a thread about yeast, not the lives of our children, we don't have to act like it is. you will disagree with this, of course. wathaug came on to the thread and detailed his opposing view without snark or condescension in only one post, he did not feel the need to defend himself or attack. amazing. it's not a matter of needing to lighten up it's a matter of discussing things in the civil way the forum rules dictate.

 

[tagz]

anyone reads through your posts on this thread would agree that you have a very strong desire to be right. this is a thread about yeast, not the lives of our children, we don't have to act like it is. you will disagree with this, of course. wathaug came on to the thread and detailed his opposing view without snark or condescension in only one post, he did not feel the need to defend himself or attack. amazing. it's not a matter of needing to lighten up it's a matter of discussing things in the civil way the forum rules dictate.

Well, in all fairness, EAZ's condescending approach to debate sets the tone for the thread.

 

[BeerGrylls]

Instead of arguing semantics, can anyone with the experience and the equipment perform a true scientific study on the difference between the 'traditional' and the proposed methods and report the findings?

 

[EarlyAmateurZymurgist]

Well, in all fairness, EAZ's condescending approach to debate sets the tone for the thread.

It's how I speak and write, nothing more, nothing less. Trust me, I am not attempting to make anyone look stupid. I am just trying to challenge the status quo. If we communicated in person where you could see my non-verbal communication, you would know that I am not attempting to make anyone look stupid. Could I have chosen a less threatening title for the thread? Yes, in hindsight, I could have used a much less threatening title. However, the thread would have passed into oblivion like thousands of other threads on this site. Now, good or bad, the thread has people at least discussing different ways of cropping and reusing yeast instead of blindly following the yeast rinsing narrative.

As an aside, I chose my current user name because all of the user names that I wanted were already taken. I finally gave up and chose a long and unusual user name that had something to do with brewing.

 

[Warthaug]

I was out on your blog. I am just curious, but why do you keep cultures that can be obtained easily through the home brew trade in your bank? I do not have access to an -80C freezer; therefore, periodic subculturing is a fact of life for me. I used to maintain a bank that was just shy of forty cultures. It was hobby unto itself. Now, I only bank brewery and culture collection cultures (at one $100.00+ each, it pays to bank culture collection cultures).

A number of reasons:

1. Its cheaper - it costs me less than $2 to grow a yeast from the bank to pitcable amounts.
2. Here (Canada), selection isn't always as good as in the states.
3. Sometimes yeast strains are discontinued (e.g. Wyeast's limited releases)
4. But mostly, its just because I like to collect strains.

Of course, I have a -80C freezer at work, so subculturing is only necessary when a stock runs low. Other methods (slants, etc) would obviously be a lot more work.

With that said, I have an interesting culture in my bank that I may be willing to trade, it's CBS 1171 (a.k.a NCYC 505, ATCC 18824, NRRL Y-12632). This stain was isolated at the Orangeboom Brewery in February of 1925 by A.C. van Wijk. CBS 1171 is a well-studied yeast strain.

I would be very interested in a trade; I'll PM you to arrange a trade.

Bryan

 

[Warthaug]

Instead of arguing semantics, can anyone with the experience and the equipment perform a true scientific study on the difference between the 'traditional' and the proposed methods and report the findings?

The next time I brew a beer I can do the comparison. However, my next batch (brewed in 1 week) is going to be an all-brett beer, so I'm not sure how useful that information is going to be for conventional brewers yeast.

Bryan

 

[orangehero]

If you're worried about boiling water as a source of contamination, a $1 jug of spring water will come UV sterilized.

 

[EarlyAmateurZymurgist]

If you're worried about boiling water as a source of contamination, a $1 jug of spring water will come UV sterilized.

It's not just the water or the source of the water; it's also all of the extra handling. I often use the acronym DMWI, when discussing yeast handling. In this context, DMWI is short for "Don't Mess With It." One risks infection every time a culture is transferred from one container to another. I only bottom crop when using a carboy (I top-crop when using a bucket, but that's another highly debatable technique). I crop into an Erlenmeyer flask after flaming or wiping the lip of the carboy with 95% ethanol and a couple of cotton swabs paired together (I have also used 91% isopropyl alcohol). The openings on both of these containers are small in comparison to a bucket and/or Mason jar; therefore, airborne microflora has a smaller surface area on which to settle.

Another positive to swirling with green beer instead of water is that green beer generally has dissolved CO2 that creates positive pressure inside of the carboy. Airborne dust is not going to enter a carboy as long as CO2 is venting from its mouth. While not as effective as a totally closed transfer system, the process does significantly limit the opportunity for airborne wild microflora pickup during the transfer.

With that said, I stand by my assertion that rinsing yeast boiled tap water is not only unnecessary, it potentially harmful to the culture as well as by the assertion that green beer is a more effective deterrent to colonization by wild microflora than boiled tap water. If one crops a culture as outlined above and it later tests positive for spoilage bacteria, then rinsing it would have made no difference because the culture was more than likely infected before it was cropped, which means that is only a matter of time before the infection renders the culture unusable because rinsing does not eliminate wild microflora.

One last thing, I concur with Warthaug's suggestion of buffering the water down in pH and/or adding ethanol. However, buffering the pH down basically pushes yeast rinsing into realm of proper yeast washing. The only differentiator will be pH of the solution.

 

[orangehero]

Contamination of a yeast culture is not an all or nothing event. The more you reuse yeast the greater the contaminants, with gradually dimishing flavor quality. There's a point where you won't be able to reuse that culture because the off-flavor compounds will reach a threshold.

I agree the extra handling is not desirable, but there's a tradeoff if you want to harvest yeast from a carboy. There's a reason why the yeast in a cylindroconical vessel isn't harvested indiscriminately.

If someone reuses a certain yeast culture only a handful of times from carboys and repitches quickly into the next batch, you may get greater negative flavor impact from all the trub than from whatever small increase in contaminants.

 

[drumuglyknuckles]

So good, thank you

Sent from my GT-I9100 using Home Brew mobile app

 

[masonsjax]

I've heard people talk about negative flavor impact from trub before, but have not experienced it personally, nor have I seen any evidence supporting or refuting such a thing. I have seen reputable members here claim that at least some of the things that make up trub are in fact beneficial to the health of a yeast culture. Until I see some evidence saying otherwise, I'm not worried about my yeast cohabiting with trub, since my experience gives me no reason to worry.

 

[EarlyAmateurZymurgist]

I agree the extra handling is not desirable, but there's a tradeoff if you want to harvest yeast from a carboy. There's a reason why the yeast in a cylindroconical vessel isn't harvested indiscriminately.

If someone reuses a certain yeast culture only a handful of times from carboys and repitches quickly into the next batch, you may get greater negative flavor impact from all the trub than from whatever small increase in contaminants.

The technique that I outlined in my original posting crops mostly clean viable yeast. A large part of being able to crop clean yeast directly from the primary has do with how one handles cast-out wort. I never use hop pellets because it is very difficult to get clear cast-out wort using pellets unless one siphons from the top of the liquid column. One can whirlpool; however, whirlpooling is only effective if the cone holds up to the amount of suction that is produced while draining one's kettle. With whole hops, a false bottom or bazooka tube (a false bottom is less likely to clog), and a immersion chiller, the hops form a filter bed, leading to much clearer cast-out wort. The amount of trub and hop particulate matter that is carried into the primary is minor fraction of what it is when using loose pellets. I repitched yeast for the better part of a year that I cropped the way that I outlined in my original posting. Most amateur brewers who eventually repitch without rinsing come to conclusion that rinsing doesn't bring much to the table.