Splitting a recipe kit / boil time?

lost_hop · February 17, 2014, 3:07am

I plan on splitting a NB recipe kit and make two 2.5 gallon batches. (2.5-3 gallons is a good fit for my equipment, space and intake).

Question: Should I make any adjustments in boil times?
Recommended boil time for 5 gal is 60 minutes. For 1 gallon batches it’s 40 minutes.
Should I go 50 minutes for 2.5 gallons then adjust hops addition times accordingly?

Thanks

glug_master · February 17, 2014, 4:26am

I would say no. To get the bitterness the recipe calls for it’s probably easier (for NB) to round off the hops and adjust the boil time rather than weighing out 100ths of grams of hops for the 1 gallon kits.

shadetree · February 17, 2014, 4:59pm

Remember that evaporation is independent of volume for a given kettle, so you’ll need to add more water for each smaller batch if boiling for the same time as with a full batch. For example: if you start with six gallons, boil 60 minutes, and end up with five gallons, your boiloff rate is 1gal/hr, so to do a 2.5-gal batch you would need to start with 3.5 gallons.