Better to over or underpitch

[rt4philly]

Hey Everyone,
I was brewing the other day and now that I wash my own yeast I don't have a clear idea of how much yeast I am pitching exactly. Which got me wondering is it better (or worse), if you had to choose, to under or over pitch your yeast. Thoughts?

 

[DocScott]

If forced to pick, I'd rather over pitch. You can figure out how much slurry to use by using mrmalty.com. That way you'll pitch the right amount and not have to answer your own hypothetical question!

 

[Cbaddad]

While I am no expert, I have read that it is a lot harder to overpitch versus underpitch. Underpitching even a little can sometimes result in off flavors due to stressed yeast. If you are harvesting your yeast, you usually can collect enough for two brews depending on style/gravity in my experience. If you are repitching the whole thing, there is a chance that is too much.

You can measure the amount of yeast if you harvest and store in mason jars. They often have a ML reading on the jars. Once the yeast is stored in the fridge for a night or so and drops out, it is easy to see how much you have. With this approach and using Mr. malty, you can be sure to pitch close to the expected range. At least that is what I do and have not hd any problems. I am sure others on here can give you more precise feedback.

 

[Cbaddad]

See, Doc, beat me to it.

 

[rt4philly]

Hmm hadn't heard of that site, good to know. I usually pitch the same amount of slurry and don't have any problems. But I always wonder how healthy the slurry is. And if it's not as healthy, should I be adding more? And then, how do I know it's healthy or unhealthy. That's the thought that keeps me awake at night (at least for the first 12 hours after pitching)

 

[rpe290]

Hmm hadn't heard of that site, good to know. I usually pitch the same amount of slurry and don't have any problems. But I always wonder how healthy the slurry is. And if it's not as healthy, should I be adding more? And then, how do I know it's healthy or unhealthy. That's the thought that keeps me awake at night (at least for the first 12 hours after pitching)

If its 12 hours of lag time, I would say go ahead and pitch more without worry! Last 2 lagers have kicked off in 4 hours (thats with a 50 degree start too, not the other way).

 

[rt4philly]

I pitched at 3pm and noticed some activity at 9pm. And this morning it was going full-bore with a nice yeasty foam on top. So not sure I need to pitch another. The gravity on this batch was relatively low at 1.042. So I'm not too concerned about stressing the yeast.

That's impressive for a lager usually they take a bit longer to get started.

 

[Xpertskir]

Most of the reading I have done says over pitching is more detrimental to the beer. That is if oxygenation and temperature control are both done correctly.

The unfortunate thing is that yeast growth rates are not very well understood and there are widely differing opinions on the matter. Kai and Jamil are pretty far off from each other, likely two of the people who have done the most research on the matter.

 

[CBU123]

Nowhere near an expert, but...

Unless you are planning to have a batched judged, a commercial brewer friend of mine told me that it is normally better to over pitch. Not necessarily an issue for you but in general terms always a good idea to plug into a yeast calculator and as I have learned, use a starter.

Chris