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Dumb Questions - Over pitching and over attenuation

So, as a new brewer, I am constantly looking to improve my yeast effectiveness (doing yeast starters, temp control, etc).

But, can you be too successful with yeast starters? Is there such a thing as pitching “too much yeast?”

In my head, I can’t see why having more yeast then necessary would be a bad thing. I would just guess that there wouldn’t be enough sugars to support a large population of yeast, and they would sink to the bottom. When racking/bottling, you would just leave them with the trub.

But… I know there has to be more to it than that. Would someone be able to explain if

a) this is even a realistic concern, and if so,
b) what the consequences would be of over pitching/over attenuation? How would I know if I did?

Much thanks in advance!
-glue

I have read that overpitching is possible, and what you get from that would be some of the same characteristics you get from underpitching - stressed yeast produce higher levels of phenolic compounds. I have never experienced that for myself, and it seems very unlikely that you will either, as you would need to pitch so much yeast that there wasn’t enough sugars to support a real growth phase, which would mean at least 3 or 4 times the recommended level.

Don’t worry about it.

There was a study in BYO about pitching rates. Results seemed inconclusive. But the study was with US-05. Other yeast may behave differently.

You may be able to find the article online. There is also a pod cast on Basic Brewing Radio on the study.

If its the same article I read, it basically said that yes, overpitching is possible, but on a homebrew scale, highly unlikely. If you use yeastcalc.com or mrmalty.com (both free), you will be able to dial it in pretty closely.

[quote=“glueslug”]there wouldn’t be enough sugars to support a large population of yeast, and they would sink to the bottom. When racking/bottling, you would just leave them with the trub.

[/quote]

This is basically what happens. Unless you pitch WAAYY too much yeast, I can’t see this being a problem. One LHBS owner was trying to tell me that they will start to cannibalize each other because competition for food is so intense. Hadn’t heard that one before.

Check out Yeast by Chris White (of White Labs) and Jamil. Great read.

Brewers make wort, yeast make beer.

I’ll try to find the article and email a copy to anyone that want’s it.

My memory of it was they pitch 1/2 rate, full rate and double rate. Items that people concern themselves with were all with in a narrow range. Taste testing was sporadic. Some liking each test sample better than the others.

Maybe if they pitched 4+ times the rate it may make a difference. Or 1/10th the rate.

Again, the BYO study was with dry US-05. Other strains may behave differently.

So with this theory, 1 smack pack/vial “could” be just fine for a ~1.050 beer like the manufactures say. Even though Mr. Malty/Yeastcalc say differently.

I have a brewing friend that uses 1 smack pack in a 10 gallon batch. His beers taste great.

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