How do you calculate how much water you lose during the boil?

**biggrizzly** · 12-31-2011, 02:04 AM

How do you calculate how much water you lose during the boil?

Now that I got a new 10 gallon pot I want to figure out how to do full 5 gallon boils without adding too much water to the finished wort prior to pitching.

dale1038 · 12-31-2011, 02:07 AM

Why would you add any water back with a ten gallon pot? Average is 1 gallon per hour. So boil 6 gallons to get a 5 gallon batch.

**dwarven_stout** · 12-31-2011, 02:07 AM

Fill it full of water and boil for an hour. Measure how much you have left, and work backwards.

bessieflames · 12-31-2011, 02:07 AM

You have to try it once. It varies based on equipment. It also varies based on how high the burner is. I lost 3 gallons per hour the first time, but I brought it down to 2 gallons an hour by lowering the flame.

**JonM** · 12-31-2011, 02:09 AM

+1 to the above. Might even want to do the whole chill too, because you'll lose a little bit more steam while chilling.

**BBL_Brewer** · 12-31-2011, 02:17 AM

Quote:

Originally Posted by JonM

+1 to the above. Might even want to do the whole chill too, because you'll lose a little bit more steam while chilling.

You don't lose any substantial volume to steam while chilling especially if your chilling method is efficient. You will however have a difference in volume due to temperature. When liquid cools it contracts and takes up less space.

**biggrizzly** · 12-31-2011, 02:27 AM

Thanks guys. If I did a dry run with just water and then chilled and measured would the loss be the same as if I were boiling wort? I just got a 10 gal boilermaker and a Blichmann burner to go with it for Christmas from the family and anxious to try it all out this Sunday.
Oh, I'm also using a 20ft coiled copper chiller.

**biggrizzly** · 12-31-2011, 02:29 AM

Quote:

Originally Posted by dale1038

Why would you add any water back with a ten gallon pot? Average is 1 gallon per hour. So boil 6 gallons to get a 5 gallon batch.

That is the point of the question... I don't want to add back, so I want to figure out how much to start with.

**Sea** · 12-31-2011, 02:32 AM

Quote:

Originally Posted by biggrizzly

Thanks guys. If I did a dry run with just water and then chilled and measured would the loss be the same as if I were boiling wort? I just got a 10 gal boilermaker and a Blichmann burner to go with it for Christmas from the family and anxious to try it all out this Sunday.
Oh, I'm also using a 20ft coiled copper chiller.

It will be close enough to work just fine. The exact amount you lose will vary a little simply because you can't set your burner exactly the same every time. You just need to get close. I typically lose about 1.25 gal/hour, but you might have a slightly different result.

brtisbuck · 12-31-2011, 11:22 AM

I have a question concerning this also. I am about to do my first full boil and was planning on only starting with 5.5 gallons and add because I don't want to end up with more than 5 gal until I get the feel for it. Do you include your LME in that amount? Say I start with 5.5g and add 6# of LME I am closer to a total of 6g right?