As long as my yeast is ready, I'll be brewing my first barleywine next weekend. I'm targeting a minimal OG of 1.100. One of the concerns that I'm learning about with a beer this big is efficiency and that many first time barleywiners fall short of the target gravity. So I've been doing a lot of note studying of my past beers (bigger ones) and came to this realization and question. For my 10.5 gallon batch of my Good Morning Stout, I used about 9.5 gallons of mash water and about 31 pounds of grain. 70% efficiency was calculated when creating the recipe. I overshot my target gravity of 1.078 and hit 1.082. My volumes were correct. With my stouts, my dark grains are cold steeped, so that water gets added to the boil to bring my volume up to where it needs to be. Here's my recipe for that...
Batch = 10.5
OG = 1.078
24 hour cold steep (room temp) in 3.5 gallons of water
Chocolate malt = 4 lb
Roasted Barley = 3 lb
Black Patent Malt = 1 lb
60 minute mash @ 155
Mash Water = 9.5 Gallons
Sparge Water = 4.75 Gallons
Total Mash/Sparge Water = 14.25
Total Water = 17.75 Gallons
80% Two Row Pale = 23 lb 10 oz
18% Flaked Oats = 6 lb 5 oz
2% Caramel/Crystal 120L = 11 oz
Here is my barleywine mash and grain schedule....
Batch = 5.5
OG = 1.100
90 minute mash @ 148 (Strike 166)
Mash Water = 9.5
Sparge Water = 3 (185)
Total Water = 12.5
2 gallon of boil off and 1.5 gallons of mash/hop loss accounted for
***Assuming 60% Efficiency***
38% Two-Row Pale – 10 lbs
38% Maris Otter – 10 lbs
20% Munich – 5.5 lbs
4% Victory – 1 lb
120 minute boil
My question is this... Except for the final volume, these beers are very similar in amount of grain and water used in the mash. Why should I expect a major drop in efficiency in brewing a beer this big? Is there more chemistry in this than I'm seeing?