Saving yeast

[wepeeler]

Thinking I might’ve under pitched by a lot on Friday. Maybe 500mL of thick slurry but it’s been in the fridge for almost 2 months. Next time I’ll do a starter…

Definitely under pitched. I like making starters with all liquid yeast. Gives you the opportunity to harvest some and pitch active yeast. Cuts down on lag time big time.

 

[rmr9]

Definitely under pitched. I like making starters with all liquid yeast. Gives you the opportunity to harvest some and pitch active yeast. Cuts down on lag time big time.

A follow up question on the under pitch issue. Would under pitching result in less yeast at the end of fermentation at the bottom of the fermenter? My first thought is that the yeast will bud and multiply to the max density allowed for by the wort regardless of where they start just take longer to get there, but I’m not sure.

 

[Kornssj]

Is there a way to calculate slurry or vial density without a microscope? Trying to figure out how much to pitch.

 

[Bassman2003]

A follow up question on the under pitch issue. Would under pitching result in less yeast at the end of fermentation at the bottom of the fermenter? My first thought is that the yeast will bud and multiply to the max density allowed for by the wort regardless of where they start just take longer to get there, but I’m not sure.

One has to figure in that yeast get tired and depleted. When they get tired they excrete undesirable things and/or do not complete the job of eating sugars as well. Under pitching results in getting to this stage a lot quicker than you want to. Healthy pitch rates with fresh yeast means they might never get to this stage and rip through to the end.

 

[redrocker652002]

One has to figure in that yeast get tired and depleted. When they get tired they excrete undesirable things and/or do not complete the job of eating sugars as well. Under pitching results in getting to this stage a lot quicker than you want to. Healthy pitch rates with fresh yeast means they might never get to this stage and rip through to the end.

That begs the question of, when using a slurry from another batch or doing a overbuild on a starter, how do you know it is too much or too little?

 

[wepeeler]

A follow up question on the under pitch issue. Would under pitching result in less yeast at the end of fermentation at the bottom of the fermenter? My first thought is that the yeast will bud and multiply to the max density allowed for by the wort regardless of where they start just take longer to get there, but I’m not sure.

I think you're right, but why not start with the best possible army to chew through the wort? I pitched a 2L Kolsch starter today at 3:30pm and I'm steady bubbling away

 

[McMullan]

My first thought is that the yeast will bud and multiply to the max density allowed for by the wort regardless of where they start just take longer to get there, but I’m not sure.

Not unless you can break laws of physics. Yeast cells multiply/bud a limited number of times, which is determined by the condition of the cells at the start. As CO2 and ethanol levels build up, wort conditions become stressful for the yeast and they drop out at a rate. If underpitched, they stop fermentation sooner than expected.

 

[Miraculix]

Ok. So here is what I have this morning. Big jar. Do I pour off the beer at the top and just use the thick stuff at the bottom? I am getting cold feet on using it. Im thinking of bagging it and trying again by overbuilding a 1.5l starter instead. The beer I took this from, on initial taste while I was bottling, didn't taste as good as I had hoped, so I don't want to mess up this batch by using a lousy yeast if that makes sense.

Discard the beer, make a starter from the sludge and then you see for yourself if it's viable or not.

 

[rmr9]

I think you're right, but why not start with the best possible army to chew through the wort? I pitched a 2L Kolsch starter today at 3:30pm and I'm steady bubbling away

I usually build a starter to pitch enough healthy yeast but for some reason I had a mental block this time. I’m at a bit over 48 hours with no discernible activity, though I had a bit of lag with the first batch. Omega Bayern lager at 50.

 

[rmr9]

Maybe I’ll sneak to the LHBS for a pack of 34/70 today just in case

 

[whoaru99]

That begs the question of, when using a slurry from another batch or doing a overbuild on a starter, how do you know it is too much or too little?

Dunno there is ever too much, within some semblance of reason.

On the too little side, I think as others have alluded to, unless you're going to do your own cell counts best you're gonna do is estimate viability of what you have based on opinions gathered, the use pitch rate calculator from there to get target count/starter size.

FWIW, here's my first attempt at saving yeast to try reuse. It's OYL-111 from a batch of maibock. Just "bottled" it last night so it's not fully settled but has come a long way.

Looks like bit more trub in there than I thought but is what it is I guess.

 

[McMullan]

That begs the question of, when using a slurry from another batch or doing a overbuild on a starter, how do you know it is too much or too little?

We can’t really over pitch fresh healthy yeast. We simply don’t produce enough for things to get negative. Decide what you consider to be a good fermentation. (It’s best to get fermentation started and finished as soon as possible, by the way, but don’t listen to me, because you have to decided for yourself.) Then determine empirically whether, for you, you’re ‘over’ pitching (wasting yeast?) or ‘under’ pitching (slow, lagging, even stalling fermentation). No fancy equipment/instruments required, just make a note of volume or weight of whatever you add. Be consistent. And note freshness, it’s not simply about ‘number of cells’ pitched; it’s the condition (including freshness) of the cells that matters too. Add too much knackered yeast, you might get off flavours coming through in the beer, but it won’t have anything to do with ‘over’ pitching fresh healthy yeast. We can under pitch physiologically as well as numerically.

 

[rmr9]

We can’t really over pitch fresh healthy yeast. We simply don’t produce enough for things to get negative. Decide what you consider to be a good fermentation. (It’s best to get fermentation started and finished as soon as possible, by the way, but don’t listen to me, because you have to decided for yourself.) Then determine empirically whether, for you, you’re ‘over’ pitching (wasting yeast?) or ‘under’ pitching (slow, lagging, even stalling fermentation). No fancy equipment/instruments required, just make a note of volume or weight of whatever you add. Be consistent. And note freshness, it’s not simply about ‘number of cells’ pitched; it’s the condition (including freshness) of the cells that matters too. Add too much knackered yeast, you might get off flavours coming through in the beer, but it won’t have anything to do with ‘over’ pitching fresh healthy yeast. We can under pitch physiologically as well as numerically.

I think I get trapped in the number instead of physiology mindset when it comes to pitch rates. A great reminder to always keep in mind.

With all that being said, should yeast from an under pitched or stressed ferment not be saved for future use once fermentation ends? Can one “replenish” the yeast with the addition of nutrients etc?

 

[McMullan]

I think I get trapped in the number instead of physiology mindset when it comes to pitch rates. A great reminder to always keep in mind.

I don’t care much about pitching rate, as long as I’m pitching more than enough, so I consider yeast condition more important.

With all that being said, should yeast from an under pitched or stressed ferment not be saved for future use once fermentation ends? Can one “replenish” the yeast with the addition of nutrients etc?

Yes, but build them back up from just a very small fraction of the slurry. A ml is plenty to start as a 1st step. Nutrients, especially containing zinc, are recommended if repitching more than once or twice.

 

[Tony B]

I use https://www.homebrewtalk.com/threads/maintaining-a-healthy-yeast-bank-long-term.678997/ along with a whole lot of people and we get good results. They are things that could be tweaked to be even better but…

I’m looking at buying some of the centrifuge vials. If you divide into 10 vials, what is the average volume?

 

[beren]

I’m looking at buying some of the centrifuge vials. If you divide into 10 vials, what is the average volume?

You’ll need at least 10ml if you split it to 10 and add diluted glycerin water

 

[duncan_disorderly]

Escarpment Labs did test brews on stored harvested yeasts (lager and kolsch) and found that performance really dropped off after 3 weeks, for both yeasts.

My approach is to pitch slurry up to a week, make a vitality starter for 1 to 4 weeks, and make a proper starter beyond 4 weeks.

https://escarpmentlabs.com/blogs/resources/yeast-storage-time-between-batches-pro-brewing

 

[wepeeler]

Escarpment Labs did test brews on stored harvested yeasts (lager and kolsch) and found that performance really dropped off after 3 weeks, for both yeasts.

My approach is to pitch slurry up to a week, make a vitality starter for 1 to 4 weeks, and make a proper starter beyond 4 weeks.

https://escarpmentlabs.com/blogs/resources/yeast-storage-time-between-batches-pro-brewing

White Labs has suggested starters for yeast older than 2 weeks old since the Yeast book came out. No reason not to make a starter!

 

[Miraculix]

White Labs has suggested starters for yeast older than 2 weeks old since the Yeast book came out. No reason not to make a starter!

This!