Pitching onto yeast cake

[HemoD]

I was wondering if there was any consensus on how long you can wait to pitch onto a yeast cake. My 'Perfect' Porter (from an HBT thread) has been in the primary for 11 days and I want to put an IPA onto the yeast. I plan on moving the porter to the secondary at 14 days. Is that waiting too long for repitching? I wasn't planning on washing the yeast, but would that be more important with this time-line? Any opinions would help, thanks.

Oh, the yeast is Edinburgh Scottish Ale WLP0028.

 

[hercher]

At 14 days your yeast cake will be fine. In fact, that is my usual time line. Washing the yeast might be a good idea to get any residue of the porter out of there, but it isn't necessary.

 

[HemoD]

Perfect, thanks.
I initially thought that 5-7 days would have been best (fresher, more active yeast); but brewing back-to-back weekends wasn't as realistic as I thought. How long do you think is too long? 21 days? 28 days?

 

[amandabab]

I don't worry how long the yeast cake has been under beer.

I do pitch onto it the same day I rack the beer off it though.
I'm usually siphoning toward the end of my boil.

 

[mewithstewpid]

may i recommend not pitching directly onto the yeast cake?

this is almost always over pitching, and MAY (MAY!) lead to yeasty flavors in beer.

instead, simply take a cup of the slurry and pitch it into the next batch. that way you are not overpitching, and dont have to wash yeast and wait for it to settle.

 

[laserghost]

I recently pitched a Russian Imperial Stout (OG was a bit low at 1.080 – but still a big beer and in the style) to a yeast cake from an Amber that was in primary for a month. I'm about to bottle to stout which was at 1.023 a couple days ago. The stout was fermenting within 12 hours.

 

[Bear419]

may i recommend not pitching directly onto the yeast cake?

This is almost always over pitching, and may (may!) lead to yeasty flavors in beer.

Instead, simply take a cup of the slurry and pitch it into the next batch. That way you are not overpitching, and dont have to wash yeast and wait for it to settle.

+1

 

[HemoD]

may i recommend not pitching directly onto the yeast cake?

this is almost always over pitching, and MAY (MAY!) lead to yeasty flavors in beer.

instead, simply take a cup of the slurry and pitch it into the next batch. that way you are not overpitching, and dont have to wash yeast and wait for it to settle.

That is something else that I was concerned about; for the obvious reasons, but also becuase I'm only adding 2.5 gallons of wort onto the yeast cake from a 5 gallon batch. Good advice, thanks.

 

[AviatorTroy]

instead, simply take a cup of the slurry and pitch it into the next batch. that way you are not overpitching, and dont have to wash yeast and wait for it to settle.

That's my preferred method and the fermentations will start like a bomb going off so I assume it's because the yeast is already active going in the fermenter.

 

[bja]

MAY (MAY!) lead to yeasty flavors in beer.

Where did this come from?

 

[Raenon]

I've heard of overpitching creating a less flavorful beer (as the minor esters produced during yeast reproduction wouldn't be created), but that this was a minor worry relative to severe underpitching.

I've pitched on a half cake (scooped slurry, left half behind, including the trub) and swirled it back into the fresh wort without any problems, including with WLP028- several batches of irish red, and one of scottish strong ale- only complaint is that this yeast is apparently rather temperature dependent, as my scottish must have gotten a little warm, and others mentioned a banana note that I can't ignore anymore. They didn't mind, but it no longer tastes right to me after it was brought to my attention. How the mind works...

 

[SledgeH]

I pitched a really low gravity beer (3% alc for beer pong purposes) onto a full yeast cake. 80 lbs of plate weights and a blow off tube later... I lost a full gallon of beer (from the 5 that I started with) to the blow off tube. You don't need anything close to the full cake for 2.5 gallons. I wouldn't use more than a 1/4 of the yeast cake. Expect things to start quickly. I pitched after a 21 day primary and I had activity in 2 hours.

 

[mewithstewpid]

Where did this come from?

from the numerous other thread i have read on here about pitching onto yeast cakes. people suggested that a "yeasty" flavor will carry over to the final product.

i put "may" in the post b/c i have no experience with this yeasty flavor.

 

[BWN]

I just did this for the first time. I was concerned about pitching onto the whole thing so I save about 3/4 of a mason jar and pitched that into my fermentor and had activity 6 hours later.

 

[bja]

from the numerous other thread i have read on here about pitching onto yeast cakes. people suggested that a "yeasty" flavor will carry over to the final product.

i put "may" in the post b/c i have no experience with this yeasty flavor.

I've never heard that and if the yeast drops out of suspension, there won't be a yeasty flavor.

 

[mewithstewpid]

I've never heard that and if the yeast drops out of suspension, there won't be a yeasty flavor.

from the wiki:

Overpitching is when too much yeast is pitched into the wort. If this occurs, the most common symptoms is a very yeasty-flavoured beer, beer that is fermented too quickly and has high fermentation temperatures as a result. This is a very uncommon in a home brewing setup for the following reasons:

Most yeast packets- even liquid yeast starters- are considered by experts in the field to be either *just* enough yeast to ferment a 5 gallon batch or even to be underpitching.

It takes a lot of yeast to overpitch.

Over pitching is most likely to occur when a home brewer is re-using yeast from a previous batch. Over pitching can occur when you pour fresh wort on top of a yeast cake of a previously fermented batch of beer.

Full Link

 

[bja]

from the wiki:

Overpitching is when too much yeast is pitched into the wort. If this occurs, the most common symptoms is a very yeasty-flavoured beer, beer that is fermented too quickly and has high fermentation temperatures as a result. This is a very uncommon in a home brewing setup for the following reasons:

Most yeast packets- even liquid yeast starters- are considered by experts in the field to be either *just* enough yeast to ferment a 5 gallon batch or even to be underpitching.

It takes a lot of yeast to overpitch.

Over pitching is most likely to occur when a home brewer is re-using yeast from a previous batch. Over pitching can occur when you pour fresh wort on top of a yeast cake of a previously fermented batch of beer.

Full Link

Yeasty flavoured beer is caused by too much yeast in suspension. Give it time to settle out, or filter the beer if it must be consumed early.

 

[amandabab]

I've never got a yeasty flavor from pitching on a cake. about 1/2 my brews are done this way.

 

[HemoD]

So I tried this on the weekend and based on what I read here, I put my wort onto about half a cup of ( what i thought was) yeast slurry. However, 20 hours later there was still no sign of fermentation so I pitched some more yeast into it and it took off about 6 hours later. Clearly, I decanted way too much material out of the carboy. I'll call this a rookie mistake and just leave more material in the carboy next time. Thanks again for everyone's input.

 

[diS]

+ for overpitching.
eg. if you brewed 5 gal batch of 1.048 and pitch 170B cells, you"ll end with approximately 800 B of cells at the end (according to yeastcalc)
That is more than 4 times greater amount than you need.

Also, C. White in his book "Yeast" warn about overpitching:
"In general, underpitching affects flavor more, while overpitching negatively affects yeast health more over generations. However, both can result in less than ideal fermentation with high levels of diacetyl, acet-aldehyde and low attenuation. Too high a pitching rate can also result in low or unexpected esters, yeast autolysis flavors and poor head retention."

He does admit that if you have to choose between under and overpitching, overpitching is little more tolerant before fermentation defects are evident, but surely not 4x than recommended pitching rate.
When I make starters from washed yeast I shoot for 10-20% greater amount just to be on safe side, but I"ll never pitch on whole yeast cake.

Just my 2cents...

 

[smccarter]

I did this on Sunday of last week... 2 days ago. I simply racked a beer into a keg, then pitched my new beer on top of the yeast cake. Fermentation started within an hour or so, and it was extremely vigorous. I moved the fermentation chamber down to 48 degrees, but it really didn't slow much, if at all. Quite a bit of debris has come out of the blow-off tube into my sterile solution so far.

My plan is to do this, in some form, for my next 5 beers. I'm brewing the same 6 beers over (including the one that I was talking about), and I want to save the 7 bucks per beer. The other reason I want to do this is to simplify the process. I've been creating a starter for every beer I'm brewing. The idea is that the starter already exists... what could be better than the yeast in the bottom of a fermenter? I've cleaned yeast in the past. It's always worked well for me, but it's quite a pain in the azz. I'd rather buy yeast than try to harvest it. Not saying that I'll never harvest/clean yeast again, but what a pain.

It's obvious that just pitching on top of the entire yeast cake is not the way to go. I think head space and a very vigorous fermentation are the two big issues I'm seeing.

My plan is to rack to keg, then siphon 1/2 or more of the yeast/trub from the carboy before pitching on top of it. I'll leave about half of the volume in the carboy and get rid of the other half. I'll let you know how it goes... will be brewing again next Saturday or Sunday.

 

[smccarter]

I brewed yesterday afternoon. Racked a beer from primary to a keg, then siphoned 1/2 to 2/3rds of the trube/yeast cake out of the fermenter. Then put the new beer into the fermenter.

This morning I had a very nice, calm, fermentation going.

I've got 3 more beers to brew like this. Hopefully they'll all go as well as this one. Really simplifies the process and saves 7 bucks a beer.

 

[HemoD]

Kudos to you sir. The two beers I have made using this technique never really turned out that great. However I'm not convinced pitching on the yeast cake is the reason why. It makes sense that reducing the pitching rate would work. Report back after you taste the products.


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