Yeast Washing Illustrated

[Jukas]

thanks.

mrmalty site says 10% viable;
yeastcalc says 45% viable.

That is a big difference. Is this just a wild a** guess, or what?

I've never seen that big of a differential. They both use either the same, or a very similar formula in their calculations. I'm guessing you entered a different production date on one than the other.

I just went and put in 5/1/2012 for production date on both sites and both gave me 10% viability.

 

[SMc0724]

Jukas, I used the "Repitching from Slurry" tab on Mr. Malty. My dates were both 10/27/2012. Otherwise, I used default values.

 

[zeg]

Jukas, I used the "Repitching from Slurry" tab on Mr. Malty. My dates were both 10/27/2012. Otherwise, I used default values.

Harvested slurry loses viability faster than professionally-packaged liquid yeast. Yeastcalc corresponds to the latter.

 

[Jukas]

Harvested slurry loses viability faster than professionally-packaged liquid yeast. Yeastcalc corresponds to the latter.

I think Jamil's calc's on viability on the harvested slurry tab is overly aggressive. Without the ability to do actual cell counting & viability staining the best we can do is make educated guesses based on assumed data points.

People who have done cell counting and viability tests have found that washed yeast loses far less than the 2% a day that Mr. Malty suggests.

http://woodlandbrew.blogspot.com/2012/12/refrigeration-effects-on-yeast-viability.html

Since I don't have a microscope to do cell counting, I have to just kind of 'best guess' wing it so I either use the viability estimate from yeastcalc as a starting point if it's a slurry less than 2 months old. If it's an older slurry, I make a small starter (300ml) and add my 20ml of thick slurry (I store washed yeast in baby food jars) and let it run to competition. Then I use Chris White's formula of 200m cells per mL saturation point to estimate my starting cell count and use that to figure out the size of starters I need to step up to.

I've stopped washing yeast however and moved to slants as it offers me better long term storage (plus my wife doesn't like 20+ jars of yeast in the fridge) and is easier to re-slant or plate out and pull pure cultures. Once I exhaust my current supply of washed yeast I'll solely use slants/plates and conical harvest if I'm going to rebrew within 10-14 days.

 

[zeg]

I think Jamil's calc's on viability on the harvested slurry tab is overly aggressive. Without the ability to do actual cell counting & viability staining the best we can do is make educated guesses based on assumed data points.

Could well be. I'm sure it's based on careful testing, but without some details on the assumptions it's making, it's hard to know whether it's applicable or not. Given his admonitions to stick with yeast that's > 90% viable, I suspect that getting super accurate estimates for months of storage wasn't a major goal.

Regardless of all that, this is the reason that the two calculators disagreed---they were calculating different things. I won't argue that MrMalty is accurate, but I do expect that a WLP vial has better storage characteristics than a mason jar slurry.

 

[jflongo]

Darn, darn, darn, I wish I would have seen this post before I just racked my Irish Stout to a secondary and dumped out the cake in the primary today

 

[LowNotes]

Just to chime in on using old washed yeast again. I brewed EdWort's Robust Porter this past weekend (1/11/13) and pitched using Notty that I washed on 2/24/12 (10.5 months old for those playing along at home).

I made a 1cup starter using 1oz of DME the morning before brew day just to wake the little guys up a bit. Decanted the liquid from my mason jat and threw my starter right into the same jar, and gave it a shake every few hours.

Fermentation started about 36 hours after pitching, and went strong for another 36 hours or so before tapering off. At this point I'm assuming the beer will turn out fine, as it acted just like every other beer I've ever brewed. So for whatever it is worth, Notty in certain conditions will definitely be viable after 10.5 months.

 

[HollisBT]

Just to chime in on using old washed yeast again. I brewed EdWort's Robust Porter this past weekend (1/11/13) and pitched using Notty that I washed on 2/24/12 (10.5 months old for those playing along at home).

I made a 1cup starter using 1oz of DME the morning before brew day just to wake the little guys up a bit. Decanted the liquid from my mason jat and threw my starter right into the same jar, and gave it a shake every few hours.

Fermentation started about 36 hours after pitching, and went strong for another 36 hours or so before tapering off. At this point I'm assuming the beer will turn out fine, as it acted just like every other beer I've ever brewed. So for whatever it is worth, Notty in certain conditions will definitely be viable after 10.5 months.

I have found that all yeast will last longer than several people expect them to when proper steps are taken.

All yeast will lose viability over time, and as a result you will have some dead cells in your washed yeast jars, and some of the sacc might need a little bit of extra time to wake up. Plan your brew day out in advance, give yourself enough time to put together a proper starter AND have a back up plan in the off case that your yeast does not start back up (either another jar of washed yeast to start, or enough time to get to your LHBS and buy fresh yeast). If your starter takes off and starts eating/breathing, it will do the same in your beer and you should have some good results.

 

[LowNotes]

I have found that all yeast will last longer than several people expect them to when proper steps are taken.

All yeast will lose viability over time, and as a result you will have some dead cells in your washed yeast jars, and some of the sacc might need a little bit of extra time to wake up. Plan your brew day out in advance, give yourself enough time to put together a proper starter AND have a back up plan in the off case that your yeast does not start back up (either another jar of washed yeast to start, or enough time to get to your LHBS and buy fresh yeast). If your starter takes off and starts eating/breathing, it will do the same in your beer and you should have some good results.

Could not agree more with the back-up plan. I keep a brand new packet of S-05 and Notty (I use those for almost all my beer so far) in the fridge just-in-case nothing happens after 2-4 days. My biggest fear is having a perfectedly made bucket of wort go to waste because I was too cheap to buy new yeast each batch.

So far so good though!

 

[zeg]

I keep a brand new packet of S-05 and Notty (I use those for almost all my beer so far)

Even if you use other yeasts, in terms of having back-ups, those are pretty good choices. They're reasonably neutral, so there aren't many beers that they wouldn't work at least reasonably well in. You might not get quite what you'd intended, but you don't have to stock a library of backup options.

 

[jonmohno]

Do you need to wash yeast if you make a starter with origional vial of yeast to put in different jars for future batches.? I do 2.5 gallon batches,so how many jars can you get out of 1 vial/starter? And how big of a starter should I use?

 

[h4mmy86]

Sorry in advance if this has already been brought up!

For those of you who harvest from 5 gallon batches, use jars with marked measurements and follow this method exactly, filling 4 jars with slurry....

How many ml thick would you say your cake is after a few days in the fridge?

Just wanna make sure I'm on par here.
I seem to get around 50ml maybe a bit less. Hard to say cuz the lowest marking on my jar is 100ml

 

[zeg]

For those of you who harvest from 5 gallon batches, use jars with marked measurements and follow this method exactly, filling 4 jars with slurry....

How many ml thick would you say your cake is after a few days in the fridge?

I did this recently and my best estimate is that I only had about 10 mL in each pint jar. On the plus side, there was essentially no visible trub. This seems to be a bit less than most people get, which may be because I pulled a big part of the cake to immediately repitch, and I probably took the best part of the rinsed slurry for that.

The cell counts were good enough to launch a starter right away, even after about 6 weeks, but I made an effort to be conservative by adding a first stage with about half a liter of low gravity wort.

 

[Aschecte]

What's the longest anyone here has stored washed yeast and effectively used it. And of course with a starter.

 

[wormraper]

What's the longest anyone here has stored washed yeast and effectively used it. And of course with a starter.

11 months for me

 

[jb3218]

After a couple of days in my secondary, I notice what looks like yeast on the bottom. Is that indeed yeast or something else. Also, I thought that once the yeast cells ate the sugars, they were no any good. Is the yeast at the end of fermentation the extra cells that were not needed? Yeast washing looks interesting and I may try it in the near future so I'm trying to understand it better.

 

[HollisBT]

After a couple of days in my secondary, I notice what looks like yeast on the bottom. Is that indeed yeast or something else. Also, I thought that once the yeast cells ate the sugars, they were no any good. Is the yeast at the end of fermentation the extra cells that were not needed? Yeast washing looks interesting and I may try it in the near future so I'm trying to understand it better.

Yeast are living organisms just like yourself, are you not any good after you eat?

What kills yeast is high alcohol levels, heat, and a few other unlivable conditions that your beer should not present to the organisms. After they eat the sugar, they go to sleep and remain in a stasis until they see prime living/feeding/multiplying conditions again.

Think of them like sea monkeys, they are kind of hard to kill.

 

[SDBreWs0624]

subscribe

 

[Jason541]

I have been washing and reusing my yeas for a couple of years now with this same technique with good success. However, I have just for the most part, been using .25gal starter wort to 1 pint jar of yeast wash per 6 gal regardless of the OG. My question is, (and I apologize if it was previously covered but I did try searching without finding any results to my liking), but lets say I just brewed a 6 gallon batch @ OG 1.057. How many of the pint jars of the washed yeast do you suggest and at what volume of starter wort do you suggest?

I have tried using Mr. Malty but I am not certain what the results mean due to the fact I am unsure how to enter the data correctly. I know, call me stupid...sometimes I just need it spelled out for me.

Thanks, any help would be greatly appreciated,
Jason

 

[TripleHopped]

After a couple of days in my secondary, I notice what looks like yeast on the bottom. Is that indeed yeast or something else. Also, I thought that once the yeast cells ate the sugars, they were no any good. Is the yeast at the end of fermentation the extra cells that were not needed? Yeast washing looks interesting and I may try it in the near future so I'm trying to understand it better.

Yes, in the bottom of your secondary that is yeast. You DO NOT want to use that yeast. That is yeast that does not flocculate well. If you were to use that yeast you will end up having a hard time clearing your beers. You want to use the yeast from your primary. Minus the rinsing of the trub, hot and cold break, hop bits and dead yeast.

 

[jflongo]

I have been washing and reusing my yeas for a couple of years now with this same technique with good success. However, I have just for the most part, been using .25gal starter wort to 1 pint jar of yeast wash per 6 gal regardless of the OG. My question is, (and I apologize if it was previously covered but I did try searching without finding any results to my liking), but lets say I just brewed a 6 gallon batch @ OG 1.057. How many of the pint jars of the washed yeast do you suggest and at what volume of starter wort do you suggest?

I have tried using Mr. Malty but I am not certain what the results mean due to the fact I am unsure how to enter the data correctly. I know, call me stupid...sometimes I just need it spelled out for me.

Thanks, any help would be greatly appreciated,
Jason

I am curious on this too. It looks like smack packs are 4.25 oz, so just over 1/2 cup, or 1/4 pint. So I'm not sure how a pint of washed yeast compares to 1/4 pint of yeast in a smack pack.

 

[zeg]

In order to use Mr Malty or YeastCalc, you need to start by figuring out how many viable cells you have. Ideally, you'd count them directly... but few of us have the capacity to do this.

What I do is to start by figuring out how many mL of condensed slurry I have in the bottom of my pint jar. The easiest way to do this if it's a small amount is to set an identical jar next to it and add water until it's to the same level as the slurry, then pour out and weigh that water in grams---that's how many mL of slurry you've got.

The next question is how many cells were in there. To do this, you've got to figure out the density in cells/mL. Basing this on the book "Yeast" and the MrMalty documentation, if you have solid yeast, it's about 4.5 billion/mL, and about 1 billion/mL if it's a thin slurry. Mine are usually pretty solid, so I usually use something like 3 billion/mL as a guess. You've probably got 10-25% non-yeast mixed in also, so you ought to scale to account for that, but it's not really necessary given the other uncertainties in this process.

Ok, so you have X mL of slurry at Y billion cells/mL, so multiply the two numbers to get your cell estimate. Now you have to figure out the viability. You can get some idea by playing with the dates on the MrMalty calculator and watcing how its viability goes, but many people challenge the general validity of its model. I usually just assume it's between 50 and 100% and plan my starter steps so that I'll have an acceptable pitch rate at either extreme.

So, for example, on my recent rinsing, I had about 10 mL of compacted slurry, which is roughly 10 * 3 = 30 billion cells. I played around with yeast calc and came up with a 3 step starter that was right at the desired pitch rate for 15 billion cells (50% viability) and was about 15% high for 30 billion cells (100% viability). Using two or three steps will reduce your sensitivity to starting count somewhat. I think I used a 500 mL first step.

Hope that helps. It's not very precise, but I think it's about the best you can do short of counting cells.

 

[DanPoch]

What's the longest anyone here has stored washed yeast and effectively used it. And of course with a starter.

2 months over a year. Or 14 months.

As has been said before if you wash the yeast well and have everything that comes into contact with it sanitized those little guys will last a long time. Yeast are much more hardy than you might think.

When I pull one of my baby-food-jar yeasts out (usually about 3/4 full of yeast slurry), I note the color and the scent of it before using a starter. Then it's into the starter and off we go.

Also +1 on having a dry yeast backup on hand. It never hurts and sometimes it will help.

 

[pabloj13]

In order to use Mr Malty or YeastCalc, you need to start by figuring out how many viable cells you have. Ideally, you'd count them directly... but few of us have the capacity to do this.

What I do is to start by figuring out how many mL of condensed slurry I have in the bottom of my pint jar. The easiest way to do this if it's a small amount is to set an identical jar next to it and add water until it's to the same level as the slurry, then pour out and weigh that water in grams---that's how many mL of slurry you've got.

The next question is how many cells were in there. To do this, you've got to figure out the density in cells/mL. Basing this on the book "Yeast" and the MrMalty documentation, if you have solid yeast, it's about 4.5 billion/mL, and about 1 billion/mL if it's a thin slurry. Mine are usually pretty solid, so I usually use something like 3 billion/mL as a guess. You've probably got 10-25% non-yeast mixed in also, so you ought to scale to account for that, but it's not really necessary given the other uncertainties in this process.

Ok, so you have X mL of slurry at Y billion cells/mL, so multiply the two numbers to get your cell estimate. Now you have to figure out the viability. You can get some idea by playing with the dates on the MrMalty calculator and watcing how its viability goes, but many people challenge the general validity of its model. I usually just assume it's between 50 and 100% and plan my starter steps so that I'll have an acceptable pitch rate at either extreme.

So, for example, on my recent rinsing, I had about 10 mL of compacted slurry, which is roughly 10 * 3 = 30 billion cells. I played around with yeast calc and came up with a 3 step starter that was right at the desired pitch rate for 15 billion cells (50% viability) and was about 15% high for 30 billion cells (100% viability). Using two or three steps will reduce your sensitivity to starting count somewhat. I think I used a 500 mL first step.

Hope that helps. It's not very precise, but I think it's about the best you can do short of counting cells.

This is exactly what I do too. Is it perfectly accurate? Probably not. But it works.

 

[jflongo]

This may have confused me more

So if I have a pint jar, and it's 1/4 full of thick yeast. That would be 118 ml. So that would be roughly 354 billion cells. So I would have to do a starter to triple this then it sounds like for a standar 5g batch?

 

[pabloj13]

This may have confused me more

So if I have a pint jar, and it's 1/4 full of thick yeast. That would be 118 ml. So that would be roughly 354 billion cells. So I would have to do a starter to triple this then it sounds like for a standar 5g batch?

Only if your viability was 100%.

 

[jflongo]

So I wonder if throwing the whole pint(thick and thin), into a 2L starter would suffice for a 5g batch.

My recipe is calling for only 2.367 tbsp(35 ml)

 

[pabloj13]

So I wonder if throwing the whole pint(thick and thin), into a 2L starter would suffice for a 5g batch.

Again. Depends on your viability. If you had 100% viability you wouldn't even need a starter. If you have 1% viability you'd needs a multi-step starter. It all depends on the age/viability of the yeast and how much other crap is in there.

 

[jflongo]

Well since my recipe is calling for only 35ml, even if I have 50% viablity, it still sounds like a pint, even it only a 1/5 - 1/4 that was thick yeast, would still be more than enough and a starter wouldn't be needed. I may still try a 1L starter just for kicks, since I've never done a starter before.

 

[zeg]

So if I have a pint jar, and it's 1/4 full of thick yeast. That would be 118 ml. So that would be roughly 354 billion cells. So I would have to do a starter to triple this then it sounds like for a standar 5g batch?

That is a whole lot of yeast. Are you certain it's all yeast? Often you can see layers with slightly different colors, where one layer is yeast and the other trub.

But yes, if you have 118 mL of pure yeast gunk (stuff so thick you can't pour), that's 350-450 billion cells. If it's all viable, then that would be enough for most beers without increasing the counts at all.