Getting 15 gallons of beer boiled in a 15.5 gallon keggle?

[thrstyunderwater]

I realize that hop utilization and carmalazation are issues I'll be flirting with.

I'm wanting to make 15 gallons of an oatmeal stout, all grain. I've made 10 gallon batches before and just want to get more beer for my time. Would I be better off boiling a more concentrated wort then diluting once it's cooled or collect ~16 gallons of run off and boil the majority in the keggle and 3-4 gallons in another pot, and combine at the end?

 

[Phunhog]

I have been thinking about doing the same thing. I think the best way would be to plan on 13 gallons of a higher gravity beer and dilute it at the very end of the boil with 2 gallons of boiling water. Obviously it will take a calculator, or at least some math to get your numbers right. I wouldn't worry about carmelization...hop utilization would probably be a little lower. Not sure how to compensate for that.

 

[Yooper]

I have been thinking about doing the same thing. I think the best way would be to plan on 13 gallons of a higher gravity beer and dilute it at the very end of the boil with 2 gallons of boiling water. Obviously it will take a calculator, or at least some math to get your numbers right. I wouldn't worry about carmelization...hop utilization would probably be a little lower. Not sure how to compensate for that.

That's the only way I can think of.

I can't FIT 15 gallons in my keg, since it's 15.5 to the top with the dome intact. I can fit maybe 12.5 without too much worry of boil overs (with Fermcap!) but that boils down to 10.5 gallons in an hour or so.

For a 15 gallon batch, you'd be starting with 17 gallons of wort. That's even close for a 20 gallon kettle, and probably better with a 25 gallon kettle.

You could use DME to make up some of the fermentables, which would probably be the easiest.

 

[beerloaf]

My last batch was 12 gal in a 15 gal kettle. It ended up being around 13.5 gal which boiled down. I didn't have a boil over but I was pretty careful. I was pretty much pushing the limits of my system.

beerloaf