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Is there such a thing as too much yeast?

Wouldn’t it just drop out of suspension?

This is a topic of much debate.

On the home brewing level I would say no. When I do no chill brews I don’t aerate after it’s cooled and dump most of the yeast from a previous batch in. They’re rockin in an hour or 2 and finish in a week to 10 days.

There definately is a risk involved in overpitching. Part of the lifecycle the yeast undertakes is a population growth (I believe it mutiplies 5 times in the case of ales.) So an overpitch would change that pattern.

How much flavor effect it would have on the beer could vary, and may not be that significant. I have been told that an ester component could come into play.

One practical observation I have made when overpitching is that temperatures can get out of control much faster. So a little more care may be needed in that regard.

Yeast growth and ester production are controlled n=by the same enzyme, acetyl co-A. When it does one, it won’t be doing the other. By pitching a large amount of yeast, there is little to no need for cell growth, so ester production increases.

So would that mean that pitching a relatively low gravity beer on top of a whole yeast cake is a bad idea?

I just brewed a batch of beer that came out to about a 1.060 and threw it on top of the whole yeast cake from a 1.058 batch of beer I made. Now hearing about the esters makes me wonder if I should have pulled some of the cake out before pitching it.

My practice for the last year or two (on the advice of Denny and others) has been to remove 1/2 -2/3 of the cake for most ales. If you are going to do a lager you would tend to leave about 1/2 - I have left a little more and it was fine.

#1 rule is that you would never pitch a low gravity beer on top of the yeast cake of a high gravity beer.

You probably should have removed a little, but I have pitched beers on whole yeast cakes without noticing too much of an issue. So you may still be OK.

[quote=“lil_Blue_Ford”]So would that mean that pitching a relatively low gravity beer on top of a whole yeast cake is a bad idea?

I just brewed a batch of beer that came out to about a 1.060 and threw it on top of the whole yeast cake from a 1.058 batch of beer I made. Now hearing about the esters makes me wonder if I should have pulled some of the cake out before pitching it.[/quote]

Yes, a very bad idea IMO. I have my own experience as well as science to back that up! When I harvest yeast, I pour it into 2-3 containers. One of those is more than sufficient for an average gravity beer under normal conditions.

I pay attention to the yeast calculators. There are several out there but I will usually go to MrMalty.com and enter my info for the beer, find how many milliliters of slurry I need (on a harvested repitch) and add about that amount, give or take. It seems like there is a good zone and being too far under or over have their drawbacks. I have mentioned this numerous times but I’m probably not very good at explaining it. But I heard the guys on the BN talking about this and they mentioned the growth stage, etc. and that flavor compounds are produced during that phase that beer drinkers find “pleasing”. When you pitch too much yeast, that phase does not occur (or occurs at a lower level?) and those flavors are not produced and as a result, you may experience a beer that is a little flat-tasting. I have also heard that a slight underpitch on a harvest repitch is okay because the yeast will be required to produce more cells and those are fresh, new yeast cells that bring their own positive character to the beer’s overall flavor. All of this info is floating unfiled around in my head… too much listening to these guys without properly sorting it all out. :stuck_out_tongue: Cheers.

This also makes me think about brewers who are trying to fine-tune their beers and the flavors they get. I think the proper handling and pitching of yeast (that includes proper aeration) is one part of that along with water composition, mash pH, etc. Anytime you hear of someone who describes their beer as “not quite right but I can’t put my finger on it” or a slight this or a hint of that… it’s probably a small thing that newer brewers may not look into until they’ve been around a little bit. Brewers mention beers that are flabby, flat, bland, too sharp, puckeringly dry, etc. and resolving those things come from brewing over & over. It’s easy to make “beer” but it’s those little nuances that can be elusive. Cheers Brothers.

[quote=“Denny”][quote=“lil_Blue_Ford”]So would that mean that pitching a relatively low gravity beer on top of a whole yeast cake is a bad idea?

I just brewed a batch of beer that came out to about a 1.060 and threw it on top of the whole yeast cake from a 1.058 batch of beer I made. Now hearing about the esters makes me wonder if I should have pulled some of the cake out before pitching it.[/quote]

Yes, a very bad idea IMO. I have my own experience as well as science to back that up! When I harvest yeast, I pour it into 2-3 containers. One of those is more than sufficient for an average gravity beer under normal conditions.[/quote]

:frowning:

Hope I didn’t ruin it. I had read about people pitching another beer on top of a yeast cake from a previous batch and about harvesting yeast, but never gave a thought to the fact that I might have too much yeast in the fermenter. Guess that will be chalked up as a lesson of what not to do in the future.

You probably didn’t ruin it, but there might be something about it that isn’t quite right - hard to put your finger on it… :smiley:

I have used whole yeast cakes in the past, but only when pitching into barley wines, RIS, imperial pilsners, etc - all beer with OG >= 1.090.

From my experience, there is nothing wrong with pitching yeast harvested from a higher gravity beer into a lower gravity beer, though I’ve never repitched from a VERY high gravity beer. If the yeast is overly stressed, I can see how that might impact how well they would work for the next brew, but I could never understand why I couldn’t reuse a portion of the cake from my 1.060 beer in the next beer just because it was < 1.060.

[quote=“lil_Blue_Ford”] :frowning:

Hope I didn’t ruin it. I had read about people pitching another beer on top of a yeast cake from a previous batch and about harvesting yeast, but never gave a thought to the fact that I might have too much yeast in the fermenter. Guess that will be chalked up as a lesson of what not to do in the future.[/quote]

Nah, you didn’t ruin it! It will likely be better with a little less yeast, but I’m betting you’ll drink every drop of the current batch!

[quote=“Denny”][quote=“lil_Blue_Ford”] :frowning:

Hope I didn’t ruin it. I had read about people pitching another beer on top of a yeast cake from a previous batch and about harvesting yeast, but never gave a thought to the fact that I might have too much yeast in the fermenter. Guess that will be chalked up as a lesson of what not to do in the future.[/quote]

Nah, you didn’t ruin it! It will likely be better with a little less yeast, but I’m betting you’ll drink every drop of the current batch![/quote]

lol, as long as it’s drinkable I’ll be downing it all. I wiped out my beer budget getting this stuff brewed so I’m getting a bit excited about drinking it since my fridge is getting pretty empty. Already started wiping out my first batch of beer, a chocolate milk stout which will be three weeks in the bottle tomorrow. My first Irish Stout is slated to be bottled next Thursday and the second Irish Stout two weeks after that. Not sure what I want to brew next or where I’m going to find the extra money for it, but… :cheers:

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