water ratio for boiling (topping up or not)?

detlion1643 said:

I do only have 1 hme brew done so far, and followed the instructions exactly. Obviously I barely even needed a boil, and only mixed the hme with a little bit of water, adding water to reach the desired gallons..

With that in mind, I want to migrate to extract, and I've been reading a lot. I understand I need to use dme/lme instead of hme, not a problem. I also know that I need to get hops and do a full 60 minute boil, utilizing the hops at different times to get bittering/flavor/aroma from them.

The part that gets me is how much water to boil with the malts and hops. As of now, I only have a mr. beer 2.5g primary available (3 5g carboys are still in use ). So, if I may ask, what are the differences and effects of the followings:
- Boil a gallon of water with dme/lme and add hops at times, top up with water
- Boil 2.5+ gallons (boil-off) with dme/lme and add hops at times, no top up needed
*Also can it be expanded to 5g+, as in boil 2+g and top up, etc...?

Will the first one result in "thinned/watered down" as the hops don't boil with all the water? Or do they pretty much equal out in the end?

Click to expand...

• partial boils will result in high kettle carmelization because you're boiling a very concentrated sugary solution and diluting down AFTER you boil. Great for a Ambers, bad for a lot of other styles of beer.
• partial boils (usually done on the stove top) have a weaker boil, resulting in less flavor-impacting melanoiden compounds being formed
• often, you're adding back unboiled, chlorinated water which can add unwanted off-flavors. Light chlorination and temporary water hardness is usually driven off by boiling.