Why Not to Pitch On Your Yeast Cake

[BigJason]

After reading all of this, I racked from primary to secondary after 12 days, and dumped half the yeast cake, then pitched a new batch of the same recipe onto the cake. I'll do some taste testing. But I will note that I have active airlock activity after just 3 hours.

First time I've pitched on a cake, I'm interested in how it works out. For some it's a science, for some it's a rigid process, for others, it's just fun.

 

[COLObrewer]

Does anyone have insights on pitching to the cake after a secondary? Is there a higher or lower percentage of viable yeast in a secondary cake as opposed to a primary cake?

It's certainly alot cleaner than primary trub, I've started going back to using secondary (at times) for the purpose of collecting a cleaner batch of re-useable yeast.

Keep on brewing my friends

 

[nutty_gnome]

While the yeast is cleaner, many posts on these boards suggest that harvesting from secondary will yield you the least flocculent and slowest performing fraction of the beasties. So, after a few washings, you have something that isn't at all like the intial 'charge' of yeast. Thats my understanding.

 

[Bob]

Nutty Gnome is Nutty, but he's not wrong.

Yeast from the clearing tank may be more free of trub, but the yeast is not of good-enough quality for use. Better to harvest yeast from the primary and pitch as-is slurry or wash the trub away.

Bob

 

[COLObrewer]

That makes perfect sense, Thanx!

 

[cheezydemon3]

Again, Bob, I admire your initiation of the discussion, and to start trouble, but the evil's of TRUB are, in my opinion, exaggerated, and in question, especially if there is short exposure to said trub.

 

[slowbie]

Again, Bob, I admire your initiation of the discussion, and to start trouble, but the evil's of TRUB are, in my opinion, exaggerated, and in question, especially if there is short exposure to said trub.

I don't recall anyone here talking about trub being such a terrible thing. The only reference I remember is when Bob said that the slurry at the bottom of your primary is only about 25% yeast whereas the bottom of a starter is nearly 100% yeast and that pitching rates should be adjusted accordingly. Did I miss something?

 

[cheezydemon3]

Nutty Gnome is Nutty, but he's not wrong.

Yeast from the clearing tank may be more free of trub, ................. to harvest yeast from the primary and pitch as-is slurry or wash the trub away.

Bob

I don't recall anyone here talking about trub being such a terrible thing. The only reference I remember is when Bob said that the slurry at the bottom of your primary is only about 25% yeast whereas the bottom of a starter is nearly 100% yeast and that pitching rates should be adjusted accordingly. Did I miss something?

sorry, not just Bob, but he definitely cites trub as one reason not to pitch on a cake.

 

[Yankeehillbrewer]

Again, Bob, I admire your initiation of the discussion, and to start trouble, but the evil's of TRUB are, in my opinion, exaggerated, and in question, especially if there is short exposure to said trub.

But don't you think it is in the best interest of your fresh wort to have a freshly cleaned & sanitized Fermentor?

I'm not sure what you mean by short exposure? your new wort will be sitting on all that old trub for at least 3 weeks, and by the time it's done the original yeast could up 2 months old or more. By that time Autolysis could become an issue, even though many claim it to be a myth of sorts. Isn't it best to just eliminate the possibility by cleaning your primary and pitching a proper amount of yeast slurry?

 

[scottlindner]

But don't you think it is in the best interest of your fresh wort to have a freshly cleaned & sanitized Fermentor?

I'm not sure what you mean by short exposure? your new wort will be sitting on all that old trub for at least 3 weeks, and by the time it's done the original yeast could up 2 months old or more. By that time Autolysis could become an issue, even though many claim it to be a myth of sorts. Isn't it best to just eliminate the possibility by cleaning your primary and pitching a proper amount of yeast slurry?

If you don't trust the sanitization of your first batch, how can you trust it in the second?

I have done as many as five beers in a series onto the same active yeast cake (I pull out at least 50% between batches). Just last night I drank one that was the third in a series that was in a keg for 1.5 years at room temp. No infection, tastes awesome. Being sanitary isn't a problem for me, but if it's your problem.. then don't repitch.

As for the affects of overpitching (the purpose of this thread), I couldn't say. I haven't done enough testing to determine any appreciable difference between batches that went onto too much yeast, from those that went onto a more appropriate or even lesser amount of active yeast.

Cheers,
Scott

 

[Yankeehillbrewer]

If you don't trust the sanitization of your first batch, how can you trust it in the second?

I have done as many as five beers in a series onto the same active yeast cake (I pull out at least 50% between batches). Just last night I drank one that was the third in a series that was in a keg for 1.5 years at room temp. No infection, tastes awesome. Being sanitary isn't a problem for me, but if it's your problem.. then don't repitch.

As for the affects of overpitching (the purpose of this thread), I couldn't say. I haven't done enough testing to determine any appreciable difference between batches that went onto too much yeast, from those that went onto a more appropriate or even lesser amount of active yeast.

Cheers,
Scott

Didn't say I had a Sanitation problem, I'm very serious about sanitation, it's the first step in making good beer. It just doesn't make sense, to me, to not clean out the old trub and the Krausen ring. It's not so much about Sanitation, but about not having all that extra crap in your fresh wort.

 

[h4rdluck]

its all just preference i guess.... I don't see it as crap...i just see it as more of the same as what i am adding. The krauzen ring? Theres just going to be another. The trub? Its just going to settle to the bottom. The autolysis? Never been a problem for me.

Again. There are plenty of theories and paper research. But what I care about it what you can actuality get away with an personally its a lot more than what a lot of people here suggest.

 

[scottlindner]

Didn't say I had a Sanitation problem, I'm very serious about sanitation, it's the first step in making good beer. It just doesn't make sense, to me, to not clean out the old trub and the Krausen ring. It's not so much about Sanitation, but about not having all that extra crap in your fresh wort.

If sanitization isn't the problem, then it's trub and autolysis you're concerned about. Both are very debatable if they'll affect your beer in any appreciable way.

When i first started repitching onto active yeast cakes I kept a rag submerged in my iodophor solution during the brew to ensure it was sanitary and used it to clean the kraussen gunk out of my fermenter. I still use a plastic pail so that's easy for me to do. I stopped doing that when I realized I couldn't tell the difference. Could judges at the NHC? Possibly, maybe even likely, but I can't tell so why bother? I haven't submitted a single beer to a competition and I don't have any intent to, so why bother, it's good enough for me. So what I think you should do is leave a beer in your primary for a month, bottle or keg, and drink. If you can tell it tastes like crap, don't repitch. If you can't, maybe you should give it a whirl.

I recently had a brew in primary sitting on dead yeast, trub, and bathing in krausen gunk for four months. I tasted the gravity sample while racking into a corny. One of the most fantastic beers I've ever made. Maybe it was just a good brew sesson, or fresher grain, or the slight amount of extra crush I added on my Barleycrusher, or maybe the trub and autolysis boggyman didn't visit my fermenter that day? i dunno which, but my first impressions with those two fears are that they don't exist.. maybe my taste buds suck?

Scott

 

[Yankeehillbrewer]

well we'll just have to agree to disagree

 

[scottlindner]

well we'll just have to agree to disagree

What's your purpose? Do you disagree that my taste buds might suck, or that NHC judges really can't taste very much?

 

[DKershner]

What's your purpose?

One strategy has a higher risk of infection, but hedges against Autolysis. It may or may not exist in homebrewing, but until someone proves it doesn't, neither way is the "right" way.

Though, to be fair, I would reuse a fermenter before washing a cake. Seems safer to me.

 

[Yankeehillbrewer]

What's your purpose? Do you disagree that my taste buds might suck, or that NHC judges really can't taste very much?

To convert this entire forum to doing things my way, which is the right way and only way. Why? Because I said so.

 

[scottlindner]

To convert this entire forum to doing things my way, which is the right way and only way. Why? Because I said so.

We agree..

 

[chriswilkes33]

Well put. It is extremely lazy and unsanitary. Bob talked me out of pouring wort onto a cake over a year ago, with many of the same arguments he made in his OP (albeit they were dumbed down for me!)

The practice of knocking out onto a cake irritates me as much as homebrewers who refuse to make yeast starters for their White Labs vials and Wyeast smack packs. Again, if something is worth doing, it's worth doing right.

Why would me not making a starter irritate you?

 

[scottlindner]

One strategy has a higher risk of infection, but hedges against Autolysis. It may or may not exist in homebrewing, but until someone proves it doesn't, neither way is the "right" way.

Though, to be fair, I would reuse a fermenter before washing a cake. Seems safer to me.

I completely agree. There's no one way, and if you look at some of great styles we enjoy today, their history of those styles evolved using very different methods.

It's my opinion that as Americans (assuming we all are), we tend to focus on the science, rather than the art, in most things. I see this thread as a good example of that. It's great to know the science, but I can show you a great beer using terrible science, and a terrible beer using great science.

Scott

 

[Yankeehillbrewer]

We agree..

That's the spirit

 

[DKershner]

That's the spirit

Do I feel a group hug coming on?

 

[Doc Robinson]

I don't understand the concept of "slurry". This is a 16 oz. jar with a compacted washed yeast cake on the bottom. How do I estimate the cell count?

 

[DKershner]

I don't understand the concept of "slurry". This is a 16 oz. jar with a compacted washed yeast cake on the bottom. How do I estimate the cell count?

It's the compacted cake. Dump out the liquid and you are left with "slurry". As for estimating, you can use the ml formula in the original post or go to mr malty's pitching rate calc.

And btw, I have both that Orange Juice and Garlic in my fridge right now.

 

[slowbie]

From what I understand from this thread, you're going to want to make a starter if you've stored that washed yeast for any longer than a week. The viable yeast count decreases enough that it is nearly impossible to estimate.

Also, Bob talks a lot about the slurry from your primary, which he estimates has only 25% of the cell count of the slurry from a starter, so make sure you're working with the right numbers for the type of slurry you're using.

 

[arturo7]

and a terrible beer using great science.

Ya mean like Budweiser?

 

[scottlindner]

Ya mean like Budweiser?

Bingo!

I was thinking of some of my early experiments in homebrewing. No science would have helped those. I just tried some really boneheaded things. but yah.. Bud is a great example too.

Scott

 

[Paddle_Head]

From what I understand from this thread, you're going to want to make a starter if you've stored that washed yeast for any longer than a week. The viable yeast count decreases enough that it is nearly impossible to estimate.

Also, Bob talks a lot about the slurry from your primary, which he estimates has only 25% of the cell count of the slurry from a starter, so make sure you're working with the right numbers for the type of slurry you're using.

I think Bob said that harvested yeast that had not been washed loses 25% viability w/in a week. Washed yeast should be more resiliant. Maybe I need to re-read it.

 

[slowbie]

I think Bob said that harvested yeast that had not been washed loses 25% viability w/in a week.

You're right, I misremembered it as being any stored yeast.

Washed yeast should be more resiliant. Maybe I need to re-read it.

I didn't find anything to confirm or deny this in my quick re-read.

 

[remilard]

its all just preference i guess.... I don't see it as crap...i just see it as more of the same as what i am adding. The krauzen ring? Theres just going to be another. The trub? Its just going to settle to the bottom. The autolysis? Never been a problem for me.

Again. There are plenty of theories and paper research. But what I care about it what you can actuality get away with an personally its a lot more than what a lot of people here suggest.

What if your goal isn't to see what you can get away with?

I have personal experience with very good homebrewers and with the laid back "everything works" hombrewers. IME, there is very little overlap between these groups.