Dark grains late in mash and absorption

[rburrelli]

Recently did a recipe for an imperial Porter with lots of dark grains which I held and added at with 20 minutes remaining in the mash.

I assumed grain would absorb about 2 gallons with the 17 lb grainbill. Ended up only absorbing 1-1/4 gallons.

Would holding back the dark grains be the cause of that?

 

[MaxStout]

Your late mash addition of dark grains would still absorb water after 20 mins.

From my empirical data I lose about 1 gal per 12 lbs. grain, so 17 lbs for me would absorb just under 1.5 gallons. While the crush could have some impact, your 1.25 gal loss seems normal.

 

[rburrelli]

Always heard .125 gallons per pound was standard. I have used that as a parameter in my Anvil 10.5 for as long as I have brewed with it.

 

[day_trippr]

fwiw, I suspect that 500-600L malts don't hold as much wort as base malts or other lighter-kilned grains. I should see if Beersmith3 pays any notice to that, but then again, it completely ignores wort losses to hops afaict, so expecting wort absorption to be indexed to malt color probably is too much to ask

Cheers!

 

[Kickass]

^^^ my thoughts exactly. Tiny little kernels of dark roasted grains likely absorbed less than big, plump, dry kilned barley.