Are cooler size/grain bed depth factors for efficiency?

[doug293cz]

I dunno - I've done two or three big beers (last one being a 24.5lb imperial stout, 1.122 @ 5.2 gallons) where I haven't jacked the strike water way up like your simulation chart...I had 8.53gal of strike (my normal 1.25 ratio + vol under false bottom - 0.875gal) for about 5.7gal FR, jacked preboil volume up to 10gals which put me at a single batch sparge infusion of 4.30gal.

Obviously a little off 5.7gal, so I was expecting a bit of a hit still. BeerSmith calc'd a 73.3% brewhouse efficiency, where I normally get 76-80%. 10gal put us at a 3 hour boil, I guess some people might call that "unreasonable". If I remember from what we collected into bottles in the end, I may have measured a shade low on vol in fermenter too, but didn't write that down on this batch.

Had a barleywine with similar results starting w/10gal preboil to end with 5.5gal in fermenter. I don't know if things are as patently dire as the simulations may lead us to believe, but they're maths, and I'm an imperfect hooman, so maybe I'm wrong somewhere along the line. Don't have preboil gravity readings / extract eff #s for those batches.

Ok, I ran your grain wt and strike & sparge volumes thru the simulator. It comes up with 79% mash efficiency (assuming 100% conversion eff.) So, a 73.3% brewhouse efficiency is reasonable if you have low kettle losses.



The "dire" numbers came from trying to get the same mash eff (87%) for a 20 lb grain bill as for a 10 lb grain bill at the same pre-boil volume. If you are willing to accept the lower eff with large grain bills, then you can keep your pre-boil volumes more reasonable. (But personally, I wouldn't be thrilled about a 3 hour boil.)

Brew on