Yeast for 10gallons

[digdan]

Do I need to use twice as much yeast for 10 gallons, or would 5 gallons work fine? I ultimatly split the yeast in half, since I ferment in two 6 gallon buckets. Should I start the yeast then split and pitch?



Thx in advance

 

[Baron von BeeGee]

Pitching amount is all about cellcount per ml. If you have an adequate level of yeast/ml for 5g and then go to 10g, you just cut your yeast/ml in half.

Short answer, your 5g level of yeast would ferment a 10g batch, but twice as much would be better. Kai had some good observations on pitching rates in a thread somewhere around here this week, but danged if I remember where.

 

[Brewsmith]

Get a good starter going, and feed it a few times to build up the cell count. It will just take a few more days.

 

[digdan]

Get a good starter going, and feed it a few times to build up the cell count. It will just take a few more days.

I got a starter going right now, how do i feed it?

 

[budbo]

I got a starter going right now, how do i feed it?

I siphon 80% of the spent wort off the cake after it finishes fermenting, then add more wort

 

[subwyking]

I siphon 80% of the spent wort off the cake after it finishes fermenting, then add more wort

bingo. after you see little activity in your starter, put it in the fridge for a few hours and the yeast will settle out to the bottom. decant (pour) or siphon the liquid off the cake, then add more wort.

 

[Glibbidy]

It may be better to slightly underpitch then to grossly overpitch your yeast.

 

[Lou]

It may be better to slightly underpitch then to grossly overpitch your yeast.

why?

 

[Glibbidy]

why?

Underpitching yeast comes with potential benefits, as well as the potential for undesired results.

Under pitching may help prevent Autolysis, By slighlty underpitching (Which most homebrewers do anyway) there is less yeast to undergo autolysis. It also takes longer for these nutrients to be depleted in your wort.

Preventing autolysis is also a good argument for using a secondary fermentation device. (but that is probably on another thread somewhere).

The deleterious effects of underpitching could result in contamination during the lag phase.

One could provide an argument for both sides of this subject until the end of time. What really matters is do whatever works for you in your lab.

 

[Walker]

Under pitching may help prevent Autolysis, By slighlty underpitching (Which most homebrewers do anyway) there is less yeast to undergo autolysis.

Is this true????

My understanding is that the yeast will multiply until they reach critical mass (or deplete all the O2 in the wort, whichever comes first) and then they will start eating sugar. If you have sufficient aeration of the wort (ie; the critical mass is what stops the growth) then it doesn't matter if you pitched a lot of yeast or a little. There will STILL be the same amount of yeast in the brew when fermentation starts . you'll have a longer lag time with less yeast (a risk for diacetyl levels), but the final yeast count should be the same.

If I'm wrong, somebody correct me, but if I'm right, then underpitching has no effect at all on autolysis at all.

-walker

 

[Glibbidy]

Is this true????

My understanding is that the yeast will multiply until they reach critical mass (or deplete all the O2 in the wort, whichever comes first) and then they will start eating sugar. If you have sufficient aeration of the wort (ie; the critical mass is what stops the growth) then it doesn't matter if you pitched a lot of yeast or a little. There will STILL be the same amount of yeast in the brew when fermentation starts . you'll have a longer lag time with less yeast (a risk for diacetyl levels), but the final yeast count should be the same.

If I'm wrong, somebody correct me, but if I'm right, then underpitching has no effect at all on autolysis at all.

-walker

WITH adequate aeration & appropriate temps underpitching should have no effect on autolysis.

Inadequate aeration, under pitching, and prolonged exposure to inappropriate could be a recipe for disaster.

 

[Lou]

ok, so you've made an argument for why underpitching is not necessarily bad (though still not inherently good, as it induces a greater sensitivity to other factors such as inadequate aeration and prolonged exposure to inappropriate temperatures). but it's still not clear to me why overpitching is bad....or why underpitching is BETTER than overpitching.

 

[Walker]

one comment; I don't think anyone is in danger of OVERPITCHING yeast, but that might depend on your definition. My definition is pitching more yeast than was necessary to ferment your beer.

The amount of yeast at the bottom of the primary fermenter after a well-aerated and properly handled batch is racked out is the BASELINE. This is how much yeast were present in your batch and did the fermentation. If you had pitched that much yeast, no growth phase would have been necessary and fermentation would start with no lag time. You would have pitched the perfect amount of yeast.

Anything more than this massive amount of yeast is technically UNDERpitching.

Anything over this is massive amount of yeast technically OVERpitching.

-walker

 

[Glibbidy]

ok, so you've made an argument for why underpitching is not necessarily bad (though still not inherently good, as it induces a greater sensitivity to other factors such as inadequate aeration and prolonged exposure to inappropriate temperatures). but it's still not clear to me why overpitching is bad....or why underpitching is BETTER than overpitching.

Basically overpitching may help encourage autolysis, and underpitching could help prevent autolysis. One must also consider adequate aeration, as well as appropriate temperatures when the pitching yeast.

Walker has a very good point, and it is unlikley you will ever overpitch your yeast, unless you pulled it from the bottom of your primary fermenter (Why the heck anyone would bother, I'll never try to understand.)
Your probably safe pitching whatever qty's you are used to pitching. As long as your yeast is healthy, you should be fine. I'm sure there must be an acceptable range within limits between under/overpitching.

 

[cweston]

...and it is unlikley you will ever overpitch your yeast, unless you pulled it from the bottom of your primary fermenter (Why the heck anyone would bother, I'll never try to understand.)

This seems like an extremely easy thing to understand. Some people are cheap bastards.

I can understand why someone might not bother, but it's not mystery why someone would bother.

 

[Glibbidy]

Good point.

Why dredge off the bottom, When you can skim off the top?

 

[El Pistolero]

Anything over this is massive amount of yeast technically OVERpitching.

Overpitching is pitching too much. Since it's virtually impossible for a homebrewer to pitch too much yeast (as you said), then there's really no such thing as overpitching for a homebrewer.