Using a yeast cake from a bigger beer

[yournotpeter]

OK - so everything I read says if you're going to rack onto a yeast cake, the wort you're racking should be from a bigger, darker beer than the one which created the yeast cake.

Well, I've got a big ol' yeast cake from a traditional bock (OG 1.070, color 18 SRM) and I'd hate for it to go to waste. Cash is a little tight right now and I was hoping to brew a simple Munich Helles (OG 1.048, color 4 SRM).

So, how bad would this be? What's the worst that could happen? Recommendations for or against?

 

[meddin]

Try this thread for a lively yeast cake pitching conversation. Some good stuff there...

https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/

 

[osagedr]

Why not just wash the yeast instead?

 

[yournotpeter]

Why not just wash the yeast instead?

Well, maybe after reading all the arguments against pitching onto a yeast cake, washing might be my best bet.

Here is what I've got - I kegged my traditional bock 2 weeks ago. The carboy with the yeast cake was put right back into the fridge...so the cake has been sitting for two weeks. I smelled it last night and it smelled great. Would it still be OK to wash that yeast? Or can I not because I should have done it immediately after I racked my beer off of it?

 

[scottlindner]

If it were me, I'd scoop out the majority of the cake. Obviously, use a sanitized spoon. I'd take out about 3/4 of what's in there. Also be sure to let it warm up for a while just like you'd do with a vial of yeast.

As for the dark to lighter. That is a good practice, but you're dealing with such a small amount of dark wort being added to a large batch that I doubt you'll notice anything.

As the others suggested. If you're really concerned, wash it. I'm sure it's still active enough that you don't need to make a starter. It's only been two weeks and I'm sure there's still some tasty sugars in there to keep the yeasties happy once you get them up to playing temp.

Cheers,
Scott

 

[Bob]

There are a lot of issues here. Let's examine them.

1. Definitely harvest and wash it.

2. You'll be wise to build a new starter from it, because storage of slurry, even under beer (the best way to store unwashed slurry), means you lose approximately 25% viability. So your slurry is probably only about 50% viable, even if it was 100% yeast solids instead of 25%. While you could pitch this directly, it's a crapshoot. If you wash it and do a starter, you'll be sure of damn near 100%-viable yeast.

3. If you wash your slurry, you can ignore any color issues.

4. More important is what happened to this yeast before it went into the Bock. Was it a fresh culture, or had it been pitched before? I don't recommend re-pitching yeast from a beer over 1.060-65, especially if that inoculation was under some strain in that ferment.

5. If the Bock was under-pitched - i.e., if you pitched one vial or XL smack-pack - the yeast was under a lot of stress fermenting this, too much for me to be confident of it in subsequent batches. Even if you pitched an appropriate amount of yeast in the Bock I'd rather you use a fresh inoculation instead of a culture from a beer of that gravity.

Cheers,

Bob

 

[broadbill]

There are a lot of issues here. Let's examine them.

1. Definitely harvest and wash it.

2. You'll be wise to build a new starter from it, because storage of slurry, even under beer (the best way to store unwashed slurry), means you lose approximately 25% viability. So your slurry is probably only about 50% viable, even if it was 100% yeast solids instead of 25%. While you could pitch this directly, it's a crapshoot. If you wash it and do a starter, you'll be sure of damn near 100%-viable yeast.

3. If you wash your slurry, you can ignore any color issues.

4. More important is what happened to this yeast before it went into the Bock. Was it a fresh culture, or had it been pitched before? I don't recommend re-pitching yeast from a beer over 1.060-65, especially if that inoculation was under some strain in that ferment.

5. If the Bock was under-pitched - i.e., if you pitched one vial or XL smack-pack - the yeast was under a lot of stress fermenting this, too much for me to be confident of it in subsequent batches. Even if you pitched an appropriate amount of yeast in the Bock I'd rather you use a fresh inoculation instead of a culture from a beer of that gravity.

Cheers,

Bob

Good points here. To add to point #3: High gravity fermentations can also stress the yeast, even at proper pitching levels. Hence, the general rule that you go from a lower OG beer to a higher OG beer.

Also, washing the yeast and/or making a starter isn't going to help in bringing this yeast back to its original fermentation specifications. You simply be propagating that mutated yeast strain forward.

This is not to say that this yeast won't work for what you want to do; all I'm saying is don't be surprised if your Helles doesn't come out according to what you usually expect for this yeast.

Hope this helps.

 

[yournotpeter]

There are a lot of issues here. Let's examine them.

1. Definitely harvest and wash it.

2. You'll be wise to build a new starter from it, because storage of slurry, even under beer (the best way to store unwashed slurry), means you lose approximately 25% viability. So your slurry is probably only about 50% viable, even if it was 100% yeast solids instead of 25%. While you could pitch this directly, it's a crapshoot. If you wash it and do a starter, you'll be sure of damn near 100%-viable yeast.

3. If you wash your slurry, you can ignore any color issues.

4. More important is what happened to this yeast before it went into the Bock. Was it a fresh culture, or had it been pitched before? I don't recommend re-pitching yeast from a beer over 1.060-65, especially if that inoculation was under some strain in that ferment.

5. If the Bock was under-pitched - i.e., if you pitched one vial or XL smack-pack - the yeast was under a lot of stress fermenting this, too much for me to be confident of it in subsequent batches. Even if you pitched an appropriate amount of yeast in the Bock I'd rather you use a fresh inoculation instead of a culture from a beer of that gravity.

Cheers,

Bob

Thanks, Bob...I appreciate your insight. The bock was actually pitched onto a yeast cake from a Mai Bock, so the bock certainly wasn't under-pitched.

So are you saying that even if I wash the yeast that I still shouldn't use it because it came from a 1.070 beer?

 

[yournotpeter]

If it were me, I'd scoop out the majority of the cake. Obviously, use a sanitized spoon. I'd take out about 3/4 of what's in there.

Thanks, Scott. The cake is in a carboy right now....any advice on how to scoop it out of a carboy?

 

[scottlindner]

Thanks, Scott. The cake is in a carboy right now....any advice on how to scoop it out of a carboy?

Oops. I didn't catch that. You could add a pinch of sterile water, swirl, and dump 75% of it. Kinda like a pour man's yeast wash. Quick and easy though.

scott