Boil size

[scorpien222]

Morning all.

I am just about to make the step from kit brewing to extract and I have a question.

Does the boil size make a massive difference ?

I.E if I do a 60 minute full boil with 5 gallons an then do the exact same recipe wait only boil one gallon but put the same amount of hops in and then just add it to the other 4 gallons of water would this make a.masive difference to the end result ??

 

[miguy96b]

It will make a difference for the hops utilization for sure. If you only boil 1 gallon then top up with 4 gallons you will dilute the IBUs down quite a bit but if you do a full boil and don't top up you will get all the hoppy goodness. I've been told full boils are generally the way to go if you can do it. Of course I will caveat that and say I only have 4 brews under my belt and only two of them were full boils so someone more experienced will step in and add more I am sure.

 

[MGBBob80]

Yes, boil size definitely makes a difference with hop utilization. http://www.brewersfriend.com/ibu-calculator/ will allow you to calculate.

 

[GilSwillBasementBrews]

Miguy had it right. You will get better hop utilization from doing full boils. Unless your doing extract batches you will generally have more than one gallon to boil anyway as you will mash grains with 1.25-1.5quarts of water per pound of grain. Most recipes are more than 3-4pounds of grain for a typical 5gallon batch. So at the very least you have a little more than a gallon just from the mash but then there is sparge water to rinse the grains plus taking into account your boil off rate usually about a gallon an hour so at minimum I'd need at least a 2gallon boil size to wind up with a gallon of wort after boiling. I usually get 6.75gallons boiled to 5.5. That gives me a full 5 into the keg.

Other than hop utilization your gravity will also be affected if you only boil a minimal amount and top off your also diluting your ABV content. IE if you had a 1.050 wort at 1 gallon and topped off to 5 gallons you'd basically have a 5 gallon 1.010 wort.