Pitching onto Cake

[duskb]

Quick question. I have a dark pale coming out of fermentation and the yeast (WLP001) did a great job on the batch. I'm planning kegging it tonight or tomorrow. My next batch is a pale ale and I'd like to pitch it onto this cake.

1. How long can I leave the cake in the fermenter at room temp (without beer on top it) before stuff gets odd?

2. Is it better to keg the batch that's there and then immediately pitch the new pale on it or does a time lag affect the yeast?

3. Any reason that I should not do this?

 

[kanzimonson]

I consider pitching onto the entire yeast cake to be one of the most despicable practices in homebrewing. It is an extreme amount of overpitching.

Use Mr Malty to figure out how much of the cake slurry you need to add to the next batch. it will only be like 100mL or so.

There are two easy things for you to do:

1) Rack off the cake on the same day you brew the next one.

or

2) Read up on yeast washing and do that.

 

[northernlad]

It is really only a good idea if you are going to use it for a huge beer.
In addition it is always best to go light to dark if you are going to reuse a cake.
AS mentioned before, you could wash the yeast and get 4 batches of viable yeast out of the one cake.
https://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/

 

[duskb]

It is really only a good idea if you are going to use it for a huge beer.
In addition it is always best to go light to dark if you are going to reuse a cake.
AS mentioned before, you could wash the yeast and get 4 batches of viable yeast out of the one cake.
https://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/

Thanks for the replies. I wash all the time and this yeast itself was washed from a former batch.

Rather than go through the hassle of washing I thought about going right on top since it was fresh (rare for me). I was aware of the color issues but didn't think it would matter for a beer that is just for my buddies (they'll drink anything).

The fact that I asked before I did it shows that I was unsure about the wisdom of it. I get the feeling it's a bad idea so I'll just wash this and go from there.

 

[PT Ray]

Use Mr Malty to figure out how much of the cake slurry you need to add to the next batch. it will only be like 100mL or so.

Yep! I'll save my slurry in a pickle jar and if it's only a week or two old I'll measure out 100ml to kick off the next batch of modest gravity. If it's a lager than at least 200ml. If it's past 2 weeks I'll proof the yeast via a 2 liter starter.

When I harvest yeast from a killer batch the last thing I want to do is use all of it for one batch.

 

[duskb]

Yep! I'll save my slurry in a pickle jar and if it's only a week or two old I'll measure out 100ml to kick off the next batch of modest gravity. If it's a lager than at least 200ml. If it's past 2 weeks I'll proof the yeast via a 2 liter starter.

When I harvest yeast from a killer batch the last thing I want to do is use all of it for one batch.

Ok so you and I are doing the same thing but here's where I've been left with conflicting reports. I have been told by the brew store guys that they never re-wash a yeast more than once (since it's possible to pick stuff up along the way) and when they do they use it right away, inside of a week or so and dump after, even if the beer turned out well.

I originally got into this discussion with them because I was having batches (random) come up with off flavors, nasty sour unidentifiable stuff, and when probing of my proceedures they told me to stay away from washing as much as I do (I was holding yeast in the fridge for months and spawning multiple generations from there). They're saying once or twice at best and then dump.

Then again, it's hard to dump this because I know it's a good strain. The last two times I've used this yeast it's been a monster, pulling the FG well below 1.010. It's hard to dump it but also not worth risking the next guy either.

Also, you mention pulling 200 ml of the slurry. How fine do you take your wash? Down to bare yeast or do you leave some trub with it? For awhile I was washing and re-washing to get down to custardy looking yeasties. Not sure there's any benefit to the extra work (and risk).


Thoughts?

 

[PT Ray]

You think breweries pitch new yeast every other batch? It's not until multiple generations that it starts getting good. I don't wash it but rather just leave enough beer to thin it out. When I'm ready to use I'll swirl it, let the trub settle and suck from the top with a turkey baster. When it gets down to mostly trub I'll toss it. I've been known to use the dregs if it's been performing well. The dregs have always turned out better then the first pitch of dry yeast. It's not until the second generation that dry yeast really gets going.

 

[kanzimonson]

Probably a better measure is "reuse until you're not confident about your yeast." Lying to yourself is the hardest thing to do.

duskb, I think that your LHBS guys are being overly cautious by only reusing once. But I'm also a little skeptical when I see someone on HBT using their yeast for 100 batches or whatever.

If you're having quality problems, then I'd recommend at least using only first generation vials is any easy way to test if your washing procedures are the problem. If you still come up with something funky, then you can keep exploring. I've been under the impression recently that a lot of our contamination issues have more to do with packing than the brewing/chilling/transferring/fermenting side, but obviously every stage is a potential source.

 

[Bottenbrew]

Not to be cynical at your LHBS either, but they DO make money when you buy yeast, and don't when you wash. Not trying to insinuate that they were saying something like that on purpose, but one does always have to wonder.

 

[Wellshooter]

On brew day I rack and then pour out about 2/3 rds of the trub and yeast in the yard. Then pour in fresh chilled wort. I've done that as many as 5 times in a row. I haven't seen any problems with it.

 

[duskb]

Not to be cynical at your LHBS either, but they DO make money when you buy yeast, and don't when you wash. Not trying to insinuate that they were saying something like that on purpose, but one does always have to wonder.

Agreed, you can't help but wonder, I know I have.

Not to mention that those guys are getting "cost" on the White Labs vials which are probably the difference of $4-5 a tube. If I was getting liquid yeast for less than $4 a tube I'd probably dump it after a generation too...

 

[Jawbox0]

Actually, if I was having sour and off flavours, I'd cut out yeast washing for awhile to try to nail down one possible infection vector. Yeast handling, done improperly, could lead to problems.

Really, anything you can do to find the problem, helps. Once you do that, then you can start going back to yeast washing and such.