Too much yeast

[penguin69]

Can you ever have too much yeast when fermenting? The reason I ask is because if you wash and reuse yeast, how do you know how much to use in the next batch. Some people break thief washed yeast into multiple jars.

 

[afr0byte]

Yes it's possible to overpitch. The wyeast/white lab sites lists rules of thumb for estimating yeast count based on volume of slurry, though I don't remember the rules off the top of my head.

 

[itsme6582]

You can indeed have too much yeast. Don't worry about it though. The only time this would really be a concern is if you are intentionally underpitching to boost ester production. Other than that, using the entire yeast cake from a previous batch would be fine. If you're washing the yeast, you'll have less than the entire cake. I can't comment on how many times you can split washed yeast and have an adequate ammount for a batch. You might try playing with Mr Malty's yeast calculator for that.

 

[barmyarmy]

In your case, you won't need to worry about too much yeast if your pitching on a cake. Even if there were such a thing as over pitching (this would have to be an astronomical amount) you would simply have to give your beer the time and temp to flock out.

 

[afr0byte]

I've only pitched up to half of a cake of yeast, but I'd argue an entire cake is likely overpitching. The effect won't be drastic, but others have reported a "flatter" beer when using an entire cake.

 

[penguin69]

Some places I have read said that they don't pitch all if the yeast cake. So that is why I asked.

So If I understand correctly that over time if you use the same yeast cake over and over eventually you will have to add more yeast. Is that correct? Or how would you grow more yeast using the same strain.

Doesn't commercial and micro brews use the same yeast strain to keep the flavor consistent?

 

[afr0byte]

Doesn't commercial and micro brews use the same yeast strain to keep the flavor consistent?

Yes they do. They don't normally take all of the yeast from one batch and pitch it in another batch, though (This is to save money and to maintain a constant pitch rate, which will help keep the flavor consistent.).

 

[barmyarmy]

Unless you are pitching an insane amount of yeast it should not affect flavor and consistency. For consistency you should be watching your temps and terminal gravity more than worrying about over pitching.

 

[jmf143]

Give this a read and decide for yourself.

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

 

[barmyarmy]

The first guy had convictions and few facts to back it up. Same old numbers that the web uses. The second guy said that biomass is biomass. The yeast is going to do what it does with a few or a lot. I agree that too much biomass may send chemical signals to inhibit growth (I have no idea, but this may cause taste problems).

 

[brewman243]

My results agree with the link above. My brews come out better when the correct amount of yeast is pitched. Recently finished one that came out pretty thin-watery, over attenuated. The recipe was designed for a lower then normal amount of yeast to develop the esters, but I made a mistake and pitched a complete starter on it. Watery, and no esters
I added some invert sugar to secondary, *not on yeast cake* to try to encourage some yeast activity again & produce some flavors.

 

[tre9er]

Pitch the right amount of yeast, or get close. As a general rule, 1/4 to 1/5 of each yeast cake is what's needed to pitch into an equal gravity, equal volume beer. This changes over time the yeast is stored, but recent experiments suggest not as drastically as you might think.

If you want to get as close as possible, use mrmalty and yeastcalc to get an idea, then when you're ready, read this:
http://woodlandbrew.blogspot.com/

Wealth of information there.