Are there any adjustments that I should make in the amount of hop additions if I’m doing a full 5 gallon boil when using one of the northern brewer extract kits which is designed for 2 1/2 gallons of water during the boil? I am using a stainless steel kettle with the built-in thermometer which needs at least 5 gallons for the thermometer to be submersed. I am not sure why but somebody told me that I should reduce the hop additions by about 10 to 15%. I reduced the hop additions by about 10% on my first batch of Caribou slobber. Not much hop flavor but I guess there’s probably not supposed to be. I’ve got a batch of pale ale fermenting right now. Added 100 percent of the hops to the boil on this batch and I’m wondering what to expect.
If you want the recipe to come out exactly as designed, then yes, reduce the hops. In reality, it’s not that big a deal. Just add them all in, you probably won’t notice much a difference. If you’re boiling 5 gallons you’re still not really doing a full boil. You’d have to boil around 6.5 gallons to end with 5 gallons.
Hop schedule for the CS extract kit:
1 oz. US Goldings (60 min)
1 oz. Liberty (30 min)
1 oz. Willamette (15 min)
Hop schedule for the AG kit
.
1 oz US Goldings (60 min)
1 oz Liberty (45 min)
1 oz Willamette (15 min)
Or maybe I mixed them up?
Let’s say you do get 10% better utilization with a full boil. If the IBU is 40, that would be 4 extra IBU’s. Not a significant change IMO. 
And do you have a scale that can measure a 10% reduction in 1oz?
