Why Not to Pitch On Your Yeast Cake

[Silentnoiz]

So what's the non-yeast washing method of repitching yeast, for someone who doesn't want to read all 5,000 pages of this thread?

It is in the first post of this thread.

 

[Denny]

So what's the non-yeast washing method of repitching yeast, for someone who doesn't want to read all 5,000 pages of this thread?

I pour the post fermentation slurry into 2 sanitized containers. Leave some beer on top of it. That's it.

 

[cheezydemon3]

I leave the yeast cake in the fermenter, scoop out (or rinse out) 3/4 of it.

Pitch cooled wort on that.

 

[Bob]

It is in the first post of this thread.

I didn't want to be the one to point that out. Thank you.

 

[M8tor]

I usually use 2 fresh packages of dry yeast without starter for a 5 gallon batch. I've occasionally pitched onto a yeast cake. After reading through this thread, I decided to use about a cup of the previous yeast cake to brew a second similar batch of beer this past weekend. The explanation of yeast regeneration just made sense to me. The results...I can't remember the last time I had such a fast start and such an active primary fermentation.

I really learn a lot from all you fellow brewers. And I like threads like this that make me rethink how I'm brewing.

Cheers!

 

[progmac]

I pour the post fermentation slurry into 2 sanitized containers. Leave some beer on top of it. That's it.

do you filter hops/break material from the kettle? about how much do you pitch in a batch of say 1.060 beer? assuming it is fairly fresh.

 

[Denny]

do you filter hops/break material from the kettle? about how much do you pitch in a batch of say 1.060 beer? assuming it is fairly fresh.

I use bags for whole hops, but pellets go through the pump and into the fermenter. No big deal. Assuming the slurry is less than a month old, I pitch about 1/2 of what I harvest.

 

[Bob]

do you filter hops/break material from the kettle? about how much do you pitch in a batch of say 1.060 beer? assuming it is fairly fresh.

I recirculate the bitter wort until it runs bright. I use whole hops almost religiously, as well as a kettle coagulant. Recirculation sets up a nice filter bed of hops petals and break material.

To determine how much, see the first post of this thread. The info is all there.

Bob

 

[mtnagel]

Bob (or anyone else), I just harvested the yeast from an IPA I made using Bell's yeast. The slurry is very thick. Almost like a milkshake consistency. It poured, but it poured very slowly. It also looked very clean. I avoided getting much trub into the fermentation bucket and I dry hopped in a muslin bag.

I know you said, "You can expect around 1 billion active cells in a ml of harvested slurry." But Mrmalty's calculator describes 1 billion cells/ml as a "thin slurry" that pours smoothly. I would not describe mine as thin.

Would you say that I should base my calculations on your high amount of 2 billion cells/ml? Mrmaltys calculator goes all the way up to 4.5 billion cells/ml for a "thick slurry".

I plan to pitch this to a 2.75 gallon 1.058 SG American brown so I don't want to overpitch a ridiculous amount.

Any advice would be much appreciated.

 

[cheezydemon3]

Bob (or anyone else), I just harvested the yeast from an IPA I made using Bell's yeast. The slurry is very thick. Almost like a milkshake consistency. It poured, but it poured very slowly. It also looked very clean. I avoided getting much trub into the fermentation bucket and I dry hopped in a muslin bag.

I know you said, "You can expect around 1 billion active cells in a ml of harvested slurry." But Mrmalty's calculator describes 1 billion cells/ml as a "thin slurry" that pours smoothly. I would not describe mine as thin.

Would you say that I should base my calculations on your high amount of 2 billion cells/ml? Mrmaltys calculator goes all the way up to 4.5 billion cells/ml for a "thick slurry".

I plan to pitch this to a 2.75 gallon 1.058 SG American brown so I don't want to overpitch a ridiculous amount.

Any advice would be much appreciated.

1/4 cup.

That is my unprofessional opinion, and the extent of thought I give to such matters.

 

[mtnagel]

1/4 cup.

That is my unprofessional opinion, and the extent of thought I give to such matters.

I like to overthink everything.

But if I assume, 2 billion cells/ml and 10% non yeast material, given the age when I pitch it this weekend and the gravity and batch size, that is the exact amount I come up with (to the hundredths place)!

If it matters, here is the yeast slurry after it sat in the fridge for for over a day. I don't see any settling or separation, so it is a very thick slurry, which makes me think I could get away with pitching less into this batch.

 

[cheezydemon3]

I like to overthink everything.

But if I assume, 2 billion cells/ml and 10% non yeast material, given the age when I pitch it this weekend and the gravity and batch size, that is the exact amount I come up with (to the hundredths place)!

If it matters, here is the yeast slurry after it sat in the fridge for for over a day. I don't see any settling or separation, so it is a very thick slurry, which makes me think I could get away with pitching less into this batch.

I respect that. The problem, as I see it, is that even after exhaustive calculations, it is still just an educated guess.

Without a microscope and some extrapolation (which still means "educated guess") you will likely end up within 1/16 of a cup of what I am suggesting.

Knock yourself out!

 

[mtnagel]

Definitely agree it's just an educated guess based on assumptions, so you're probably right that I'm over thinking it, but I can get mrmalty's calculator to tell me to pitch all the way down to 1/8 of cup, which is more than 1/16 of a cup difference from 1/2 cup Seems scary that I could be pitching 4 times too much yeast (or more) though. That's why I questioning what I have.

 

[junior]

It also has a lot to do with homebrewers thinking they're doing something worthwhile, but they're not. Here are a couple of simple facts:

1. Hundreds of years of dealing with yeast have taught us that the best place to temporarily store yeast intended for repitching is under beer. Not boiled water - beer. Not any other substance - beer.

2. As others have pointed out, what homebrewers call "yeast washing" is really "yeast rinsing". It's another technique the homebrew community has taken from professional brewers in a half-assed way because they don't fully understand it (like hot-side aeration, ad nauseum). Then - worse! - they over-think the activity, and back-document into all manner of pre-determined justifications and call it "science".

3. Then things take on the proportions of religion. "ALWAYS wash your yeast!" "Just pitch right on to your yeast cake!" "NEVER rack your beer!" "If you splash about in your beer you'll ruin it!" They're all kind of good ideas. There's a kernel of truth at the core of each. Unfortunately, the reasoning behind them is frightful if it exists at all, the mysticism surrounding the kernel of truth at the core is blown out of any semblance of proportion, adherents are more rabid the less they truly understand what they're talking about - you know, just like religion.

Anyway. I need to get back to work.

Bob

Robert,
Came back to this thread after a long time,
Bravo!

 

[sawbossFogg]

This is the thread I've been looking for, thanks Bob


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[PHDrunk]

Hi Bob et. al, great post!

Quick question about pitching rates. In the OP, you advocate a million cells per deg. Plato per ml as a nominal pitching rate. You also mention that a controlled increase in pitching rate can be used to limit ester production and produce a 'cleaner' beer (as per your brewery experience). Similarly, I have read that a controlled under-pitch can be used with Belgian strains to accentuate the characteristic flavors from those strains. This, to me, is really reminiscent of mashing where you have a nominal single infusion temp of ~ 153F, but one can mash hotter or colder to tailor the beer to style. As a result, there's a window of 150 - 158F that brewer's use to influence the flavors of the beer and the fermentability of the wort [Palmer, How to Brew, ed. 1].

From that standpoint, can you comment on an equivalent range for pitching rate? Maybe something like 0.7 - 1.3 mil/deg. P/ml, where 0.7 ensures lots of ester production, and 1.3 limits it? I think establishing some sort of range would go a long way in creating another useful tool for brewing great beer and also potentially giving some insight into the tolerances for estimation of viable cell count.

Thanks!

 

[scarnera]

Can anyone contribute any insight to yeast cakes with a collection of bugs included? I have seen recommendations of re-using the yeast cake through NB videos. I see the benefit of trying to leave behind as much trub as possible through a simple swirl and re-pitch onto fresh wort, but would this be good practice with a year or more collection of bugs included?

Thanks in advance.

 

[brewski09]

FYI, you posted this to the forum dedicated to not repitching. You may want to look up the one that advocates repitching your yeast for better answers.

I assume by bugs you mean sour bugs. I'm under the impression that when using bugs you should start fresh every time because the ratios are likely to be off. Some grow at faster rates than others and you won't get a consistent product if you repitch the yeast with bugs.


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[Quaffman]

I just racked a 1.073 brown ale pitched with about 1 6oz of 4th generation wlp002. For anyone doubting autolysis in homebrewed beer I'm here to tell you it's real. I have it to a small degree, but it's there. I didn't wash the yeast and I think that was the fatal flaw. From now on, I'll be adding less to my jars and then rinsing it right before pitching. I had no additional room for rinsing water in my jar, so I added most of its contents without the proper cleaning. How do I know it's autolysis and not some random infection, try racking a pale ale that's been sitting on the yeast cake at room temp for 9 months, then you'll know. That was a very unpleasant experiment. Burnt rubber is all I can say. Oh well, live and learn.

 

[Denny]

I just racked a 1.073 brown ale pitched with about 1 6oz of 4th generation wlp002. For anyone doubting autolysis in homebrewed beer I'm here to tell you it's real. I have it to a small degree, but it's there. I didn't wash the yeast and I think that was the fatal flaw. From now on, I'll be adding less to my jars and then rinsing it right before pitching. I had no additional room for rinsing water in my jar, so I added most of its contents without the proper cleaning. How do I know it's autolysis and not some random infection, try racking a pale ale that's been sitting on the yeast cake at room temp for 9 months, then you'll know. That was a very unpleasant experiment. Burnt rubber is all I can say. Oh well, live and learn.

I don't rinse yeast and I have never had autolysis. Are you saying that you left the yeast sitting at room temp for 9 months, or is that just an example? If the yeast I'm reusing is more than a month or 2 old, I rebuild it with a starer.

 

[Beernik]

The only time I have thought about pitching on yeast cake is when doing a ~1.100 barleywine. I was thinking of doing a 5 gallon 1.040 SMaSH as the starter for it. I'd rack the SMaSH off the yeast and rack the barleywine onto it.

It gets me to a 1.21M cells/mL/P pitch rate using brewersfriend's calculator.

Do you guys think this would work? Or should I go the tradition route of building up a starter from a stir plate?

 

[Yooper]

The only time I have thought about pitching on yeast cake is when doing a ~1.100 barleywine. I was thinking of doing a 5 gallon 1.040 SMaSH as the starter for it. I'd rack the SMaSH off the yeast and rack the barleywine onto it.

It gets me to a 1.21M cells/mL/P pitch rate using brewersfriend's calculator.

Do you guys think this would work? Or should I go the tradition route of building up a starter from a stir plate?

No, that's fine. That's what I like to do for lagers- make a small batch of a 1.040 lager, then use the yeast cake for a bigger lager. Since for one batch, I'd need a 3 gallon starter anyway I decided to make a 2.5 gallon batch of beer and then have enough yeast for my dopplebock.

 

[Quaffman]

I don't rinse yeast and I have never had autolysis. Are you saying that you left the yeast sitting at room temp for 9 months, or is that just an example? If the yeast I'm reusing is more than a month or 2 old, I rebuild it with a starer.

No, I've left beer sitting on the yeast at room temp for 9 months in the past. That's how I was able to identify the autolysis flavors and aroma. The yeast I used for the brown ale was only in its 4 generation, but was harvested from the previous batch 1.5 weeks prior. I went ahead and pitched more because it was a little higher og and the yeast had been sitting a little while. It's carbing up now, so it'll be interesting to see how it turns out. I jay checked and I probably pitched about 24 ozs of the slurry, so I obviously overpitched, which is probably the reason for the flavor.

 

[spetp]

Sub


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[Quaffman]

So, the brown ale never did get much better. I fed it to the snails and made way for an awesome citra pale ale, so no complaints. I'll be washing the yeast from now on.

 

[Denny]

So, the brown ale never did get much better. I fed it to the snails and made way for an awesome citra pale ale, so no complaints. I'll be washing the yeast from now on.

Are you certain that was the problem? I haven't washed yeast in the several hundred batches and have had no problem with not washing it.

 

[Quaffman]

Pretty sure. I'd say I'm pretty familiar with the autolysis flavor now. No big deal really. Just gotta revamp my process a little and hopefully the issue doesn't pop back up. I'm planning on going to nhc in san diego next year. Maybe I'll see you and we can talk more about it then. I think it was a combination of the over pitching and amount of dead yeast in the pitch. I am currently working with some wlp090 and repitching that by washing it first. We'll see how that goes.

 

[masonsjax]

I'm skeptical as well. I too have made several hundred batches with zero yeast "washing" and zero autolysis, despite the occasional batch that sits for several months in primary. I even had one light style sit for over 7 months without issue. There must be more pieces to this puzzle. Perhaps temperature, initial yeast health, water quality/chemistry, ... ?

 

[Denny]

I'm skeptical as well. I too have made several hundred batches with zero yeast "washing" and zero autolysis, despite the occasional batch that sits for several months in primary. I even had one light style sit for over 7 months without issue. There must be more pieces to this puzzle. Perhaps temperature, initial yeast health, water quality/chemistry, ... ?

My thoughts exactly....

 

[Bamsdealer]

Made a10% triple ipa and used at least half a yeast cake from a 6.5% ipa on Saturday. Those yeasties were ready to go. It was fermenting within the hour. Im wondering if I overpriced. I usually use closer to 1/4 of a cake for 1.060 ish beers and they always take at least several hours to show airlock activity. Could be the yeast too. It was my first go around using 2nd generation White labs 090 san diego super yeast.

Count another who has experienced a thin beer after pitching onto an entire cake. Hope I didnt pitch too much this go around as the hop bill alone for the triple ipa was a good $20