Boil off issues! Help!

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Feb 5, 2014
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I am new to this hobby and have had great fun with it. I did a brew a couple weeks ago and my target batch size was 5.5 gallons. I ended up getting about 4.5 gallons. How do I calculate boil off and how do adjust for it? do i just add more water to the boil? Also I have seen a lot of talk of target gravity. Like I said I am new to the hobby and was wondering if it is a problem to get higher OG. I can understand the problem with the OG being to low but wouldn't a higher OG make the beer stronger? I know its a lot of questions but I am the only one of my friends that is into this hobby and don't really have anybody to corner and question/ mentor with. Thanks for the help!:mug:


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Aug 29, 2011
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San Diego
It's basically just something you learn about your process- every system is different. You can get a rough estimate by filling your boil kettle to the volume you like to start the boil with, and boiling that for an hour. That should be enough information to estimate how much you need to start with next time to get the batch size you want.

Since you're just boiling off water and not malt, you can just start with more water (assuming you're an extract brewer at the moment) if you're boiling off more than the recipe estimates, or less if you're boiling off less.

It will vary a small bit with wort strength, humidity, and temperature/wind conditions, but once you've figured out what your boiloff is, you'll just take it into account when figuring out how much water you need for the brew day.