boil question

[fsa]

Probably a dumb question. How hard does the boil have to be? I've always done a very fast full rolling boil. When I bottle I only end up with a bit over 4 gallons. Once the boil starts would a slower boil suffice so that I end up with more beer?

 

[MHBT]

I like to boil so it vigorously rolling but not jumping out of the pot..a nice steady roll is all you need.

 

[chickypad]

As above you really just need a rolling boil not overly vigorous. Whatever level you decide you should try to make it consistent batch to batch, then figure your boil off into your recipe/process. For example if your recipe is designed for 5 gallons into the fermenter then you need to add the boil off loss to your starting boil volume (or plan to top off with water after if you can't boil that much). You also have to realize there will be fermenter losses. That is why many people design a recipe for say 5.5 gals into the fermenter, so you get a full 5 gal packaged. If you're brewing kits then you are stuck with whatever volume the kit plans for, unless you want to modify it a bit.

 

[doug293cz]

Recent thinking seems to be boil-off volume should be something like 7% - 10% of your pre-boil volume. This has been determined to be enough to eliminate DMS (and its precursors), and will minimize heat damage to the wort. With extracts, most of the DMS/precursors have been eliminated in the extract production process, which is why extract additions late in the boil don't cause problems. With extract brewing you need a "long" boil only to get the desired hop utilization (alpha acid isomerization.)

Brew on