Affects on IBUs using more water than recipe calls for...

[mikeljcarr]

If I boiled 3 gallons as opposed to the 2.5 recommended in the recipe would it increase the final IBUs. Would there be other effects to the beer?

 

[ncbrewer]

If you use any brewing software, it will show you how much increase in IBU you will get. You can also use it to adjust the hops to keep the intended bitterness.

You should also get a little less caramelization of the extract and less darkening of the wort - should be a good thing.

 

[cmybeer]

One of the effects of boiling more wort is increased hop utilization. That is why many people suggest jumping up to a full boil even for extract or if it is a high gravity beer making late additions of extract. Basically the more sugars in there, the less effective the hops are so by boiling a bit more wort you will get slightly better hop utilization.

 

[twistr25]

Also if the recipe batch is for 2.5 gallons you'll want to add a little more water so it allows for it to boil off back to your desired final volume.