[Clint Yeastwood]

I am about to brew an imperial stout with 16.5 pounds of grain.

I see a lot of people saying you have to pitch lots of yeast to make an imperial stout. I have a recipe for an ale, and it's just as heavy as the stout. It goes off fine with one packet of Abbaye. Finishes fast. I kegged the last batch 5 days after brewing.

Is it really true that big beers have to have a lot of yeast? I would think that the more sugar there was in a wort, the happier the yeast would be.

Another question: if this beer fizzles, is there any reason not to use Abbaye to get it going again? I don't want phenols and esters, but my understanding is that they are produced early in fermentation, so I would think they wouldn't be a problem in a beer that was kickstarted after it was mostly fermented.

Finally, I am considering trying Kveik Lutra in dry stout. It's supposed to be very vigorous. Would it also be a good choice for waking up a stuck fermentation?

[narcout]

I would think that the more sugar there was in a wort, the happier the yeast would be.

A higher gravity wort puts more osmotic pressure on the yeast.  I think whether that has a detrimental effect on performance (or how much) is strain dependent.  It also means higher alcohol levels as fermentation progresses, which can negatively affect performance as well.

[denny]

I am about to brew an imperial stout with 16.5 pounds of grain.

I see a lot of people saying you have to pitch lots of yeast to make an imperial stout. I have a recipe for an ale, and it's just as heavy as the stout. It goes off fine with one packet of Abbaye. Finishes fast. I kegged the last batch 5 days after brewing.

Is it really true that big beers have to have a lot of yeast? I would think that the more sugar there was in a wort, the happier the yeast would be.

Another question: if this beer fizzles, is there any reason not to use Abbaye to get it going again? I don't want phenols and esters, but my understanding is that they are produced early in fermentation, so I would think they wouldn't be a problem in a beer that was kickstarted after it was mostly fermented.

Finally, I am considering trying Kveik Lutra in dry stout. It's supposed to be very vigorous. Would it also be a good choice for waking up a stuck fermentation?

Yes, bg beers need more yeast. But I wouldn't call that a big beer.

[Clint Yeastwood]

Hard to impress you with 1.084.

[John M]

Go to Mrmalty.com and do the calculation. Yeast quantity is very important.

FYI, what I like to do is brew a session beer first (nothing over 5-6% ABV), and it essentially serves as a giant yeast starter. Then you have all the yeast you need for a BIG beer, plus some to save for a future batch, if you like.

Yeast can be expensive, and this is a great way to save some cost and add to the fun!

[denny]

Hard to impress you with 1.084.

  or I need to do a better job at math!

[denny]

Go to Mrmalty.com and do the calculation. Yeast quantity is very important.

Yeast health is more important IMO

[Clint Yeastwood]

The mash is over, and man, this is harder than a typical ale. This stuff does NOT want to leave the bag. I squeezed the daylights out of it. I got my wife to help, and she became obsessed.

I am going to run a couple of quarts of hot water through it and call it a day. I'm not sure how much wort I have in the boil kettle, but whatever it is, it's at 1.091.

UPDATE: I put the oven rack on a cooler, ran about 2.5 quarts of water through at around 170, and squeezed like hell. I ended up with what looks like more than 5 gallons at 1.085, by Smartref. I think I won.