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General Category => All Grain Brewing => Topic started by: breslinp on April 03, 2011, 07:54:30 am

Title: Big Beer Kits and Efficiency
Post by: breslinp on April 03, 2011, 07:54:30 am
I brewed an Imperial Stout kit last night. My first big beer (5th all-grain). The kit was for all-grain 5 gallons and assuming 75% efficiency (determined by throwing the recipe in BeerSmith). I got 60% efficiency (I've been getting 75-80% on beers 1.034-1.060 in OG). I wasn't really close on my numbers (1.090 expected, 1.076 actual). I threw in some DME to help, but only had 1lb on hand. I adjusted my 60 minute hop addition to keep the IBU/SG ratio in the original recipe.  Was there anything else I could/should have done? Should I throw in some sugar in the fermentation to try to get the FG lower?

After not hitting my numbers, I read a little and it seems 60% efficiency is reasonable for big beers. Is there anyway to increase that besides crush which I don't have control over? I guess I just need to buy extra ingredients based on the 60% efficiency. I'm a little disappointed that they sell that kit the way they do. It's a bit false advertising. There should be a disclaimer/warning.

It was a good learning experience though. Beer will be good just off my mark.  :D
Title: Re: Big Beer Kits and Efficiency
Post by: denny on April 03, 2011, 09:35:01 am
As long as you can't control the crush, about the only ting you can do is to sparge more, collect more wort, and boil longer.  You need to be careful not to oversparge, though.
Title: Re: Big Beer Kits and Efficiency
Post by: malzig on April 03, 2011, 11:23:28 am
Mathematically, it is technically possible to just hit 75% efficiency on a 1.090 beer with a single sparge and 15% boil-off, but you need to hit 100% conversion.  Homebrew shop-crushed grain can make that conversion rate difficult, since it is typically under-crushed, in my experience.  If you don't have the luxury of your own crusher, a step mash to a higher temperature alpha rest, a longer mash and even a brief decoction can help you get closer.  In addition, on such a big beer, you should get another 4-5% with a second batch sparge, with no real risk of oversparging, even without collecting extra volume and a longer boil-off.  Collecting extra sparge volume and boiling longer would also help.