Though I'm a total n00b to brewing (got my first 2 batches fermenting right now), I've been geeking out hard on the topic of hops utilization in extract brewing. I've got a typical stovetop set-up: 3 gallon boils, topping off to 5 in the fermentor. I'm focusing on IPA to start, so the issue of hops is a big one for me. So I got Beer Alchemy and plugged in the Northern Brewer Chinook IPA and Three Hearted IPA recipes as-is, and this is what I got (pay attention to IBU):
Chinook IPA Partial Boil Early Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/51AE9C9E-5A31-4787-87ED-31A33DD4D083.html
Three Hearted IPA Partial Boil Early Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/83D3DB9E-4D5A-447B-B91C-D446F717F2D8.html
I changed these up to use 1/3 of the extract at start of boil and the rest at the end (I added the rest at 20 minutes to end of boil):
Chinook IPA Partial Boil Late Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/961978B5-1696-49E9-A8BD-CDA82314F78F.html
Three Hearted IPA Partial Boil Late Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/63041ADE-C244-4DD2-95A1-61BB185999CB.html
Notice:
Chinook Early = 40.4 IBU
Chinook Late = 62.9 IBU
Three Hearted Early = 46.1 IBU
Three Hearted Late = 89.7 IBU
Another thing to consider is that these recipes call for 2.5 gal boils. Plugging that in gives:
Chinook Early = 34 IBU
Chinook Late = 58 IBU
Three Hearted Early = 37 IBU
Three Hearted Late = 82 IBU
Talking about the AIPA style, wouldn't anything less than 40 IBU be under the mark? So At a minimum, it seems doing 3 gal boil is a good start. The late extract technique produces a huge return, according to Beer Alchemy.
But how reliable would you say these outcomes are? In light of some conversation I've heard that extract density in the boil does not affect AA isomerization effeciency, I'm really curious to know if there is any way to accurately calculate IBUs in a partial boil.
For giggles I went ahead and plugged in the Chinook Recipe as a full boil:
Chinook IPA Full Boil Early Extract Addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/CA4767F6-0401-4D38-A2B8-3FFFDAA05A6F.html
Chinook IPA Full Boil Late Extract Addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/6FA66A03-1108-442E-9D35-ED94B9640CAF.html
The IBU Spread is again about 20
Full Boil Early: 57.3 IBU
Full Boil Late: 77.4 IBU
Chinook IPA Partial Boil Early Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/51AE9C9E-5A31-4787-87ED-31A33DD4D083.html
Three Hearted IPA Partial Boil Early Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/83D3DB9E-4D5A-447B-B91C-D446F717F2D8.html
I changed these up to use 1/3 of the extract at start of boil and the rest at the end (I added the rest at 20 minutes to end of boil):
Chinook IPA Partial Boil Late Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/961978B5-1696-49E9-A8BD-CDA82314F78F.html
Three Hearted IPA Partial Boil Late Extract addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/63041ADE-C244-4DD2-95A1-61BB185999CB.html
Notice:
Chinook Early = 40.4 IBU
Chinook Late = 62.9 IBU
Three Hearted Early = 46.1 IBU
Three Hearted Late = 89.7 IBU
Another thing to consider is that these recipes call for 2.5 gal boils. Plugging that in gives:
Chinook Early = 34 IBU
Chinook Late = 58 IBU
Three Hearted Early = 37 IBU
Three Hearted Late = 82 IBU
Talking about the AIPA style, wouldn't anything less than 40 IBU be under the mark? So At a minimum, it seems doing 3 gal boil is a good start. The late extract technique produces a huge return, according to Beer Alchemy.
But how reliable would you say these outcomes are? In light of some conversation I've heard that extract density in the boil does not affect AA isomerization effeciency, I'm really curious to know if there is any way to accurately calculate IBUs in a partial boil.
For giggles I went ahead and plugged in the Chinook Recipe as a full boil:
Chinook IPA Full Boil Early Extract Addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/CA4767F6-0401-4D38-A2B8-3FFFDAA05A6F.html
Chinook IPA Full Boil Late Extract Addition
http://homepage.mac.com/adsomers/BeerAlchemy_Pages/6FA66A03-1108-442E-9D35-ED94B9640CAF.html
The IBU Spread is again about 20
Full Boil Early: 57.3 IBU
Full Boil Late: 77.4 IBU