So I've been making 7-8% beers lately and I wanted something I could drink more than two of. I BIAB and my efficiency is all over the place, so I set Beersmith to 70% and hope to get close. I adjusted the grain profile and ended up with 2 lbs 4 oz Corn, 2 lbs 4 oz 6 Row, and 3 lbs 2 Row to get to 1.034 OG in a 5.5 gallon batch.
Brewed it all up last night and ended up with 1.044 OG, which will come out to 5.8% if I get down to 1.000 FG. Go figure I get 81% efficiency when I didn't want it! Maybe the difference is the corn in the mash giving me better efficiency than all grain?
Anyhow, I was hoping someone can tell me if they had this experience, and/or how the beer turned out. I'm thinking I might need to add a bit more dry hops to offset the higher ABV.
Also it seems beersmith doesn't account for grain absorption, it comes up with 8.91 gallons strike water for a 5.5 gallon batch whether you are using 6 lbs grain or 16 lbs. I ended up extending my boil for a whole lot longer than I should have.
LHBS only had 1lb of 6 Row so they recommended I make up the difference with Golden Promise. Does that sound right?
The more I think about your post the better answer I will have for you. Thought about it during my 3 hour commute to work. Let me start with your direct questions.
Corn will NOT give you better efficiency. The reason is, it doesn't have the enzymes needed for the starch conversion.
As for your question about adding more hops. The dry hopping will only add more aroma and some flavor perceived through aroma. It won't change your IBU number. If your IBU is within 5 points of the target. Don't worry about it at this point. 5 points IBU is nearly indistinguishable.
Grain absorption is usually 0.1 gallon per pound. I usually use 1 quart per pound to dough in and 2 quarts per pound to sparge. I make up for the grain absorption in the sparge. I'm a traditional AG'r with mash and a batch/fly sparge.
Your question about the golden promise. It's not good sub for an adjunct heavy grain bill. 6-Row barley is a high enzyme grain. It's predominately used with adjunct brewing; flaked corn, rice, wheat, oats and barley and it's very cheap. Golden promise is supposedly a great grain for Scottish styles. That's its origin. I have never used it but recently contemplated buying a 50 pound bag. I wound up buying 50lbs of Maris Otter instead.
I normally use Briess Pale Malt. It's fairly cheap and fully modified it's slightly darker (+1 lovibond) than standard two row. About 3 total. Pale malt also has enough enzymes to convert adjuncts too, but it has a limits that I can't recall. 6-Row is generally cheaper than pale malt and is the go to grain if you want good efficiency with adjuncts. Especially if it's 33% adjunct. It's never 100% of the grist though. Match it 1:1 with the adjuncts. 2 lbs flaked corn : 2 lbs 6-Row.
As for grain selection and another tip to help efficiency/attenuation, make sure you limit your use of crystal malts. Anything over 40L shouldn't be over 7% of the grist otherwise you'll have problems. The mash extraction could be lower and the wort won't attenuate like expected. If you need it darker or higher SRM value use Dark Belgian candy sugar or Invert Sugars; like #3 or #4. Another alternative is to use some Demerara Sugar or Turbinado Sugar up to 20% max. 10% is my preference. It's not gonna get it as dark as the dark Belgian candy or the #3/#4 inverts.
Hope this helps.
I think you're gonna have a fine light beer for after mowing.