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Old 02-11-2013, 08:55 PM   #11
Punx Clever
Nov 2007
Posts: 251
Liked 46 Times on 31 Posts

Originally Posted by bmboileau View Post
Thanks for all of this, I really appreciate the help! Just a final few concerns, does the 1.25 quarts / 1lbs of grain stand as a good mash volume? Does a full boil mean that you mash and boil with a certain volume and never top up that water? If yes, how do you adjust for water lost when removing the bags / during the boil? Do you just add more water than you need?
A full boil means that everything that goes into the fermenter came from the kettle.

To make a 6-gallon batch of beer, I start my boils at 7.5 gallons. During the 75 minutes (my normal boil time), I lose probably 1.25 gallons, and leave another .25 gallons in the bottom of the kettle / absorbed by the hops. It's not starting with more water than I need... it's starting with exactly the right amount of water!

Now, the big problem with doing a partial boil then topping off the fermenter for all grain is that you don't have enough water to get the sugars out of the grains. There is a certain maximum level of sugar you can get water to absorb. Most people "sparge" their grains by running additional water (in addition to the 1.25 qt./lb) through the grains and into the kettle, pulling out more sugar with fresh water.

Sounds like you got poor efficiency because you didn't have enough water to pull that much sugar out.

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Old 02-11-2013, 09:14 PM   #12
Nov 2010
Solway, MN
Posts: 10,036
Liked 1878 Times on 1488 Posts

I do BIAB all grain in a 20 qt (19 L) pot but to get the BIAB system to work for me I do half size batches. I start with about 15 L of water, bring that to strike temperature. This will be closer to 2.5 qt/lb. Stir in the grains and let them sit at mash temperature. Pull the bag out and squeeze out all the wort you can. Then start raising the temperature for the boil. I estimate how much water will boil off (about 3.5 L for me) and check the level of the water in the pot. If it is too low I can pour a little more through the bag of grains to extract a little more of the sugars and add that to the pot. When the boil is nearly over if I have too little wort, I can add a little water to the boil. If I have too much, I can boil a little longer to get my amount I want to go into the fermenter. By adding the water during the boil it will mix properly instead of stratifying.

The key here is to start with all or nearly all the water that you want in the fermenter plus the amount you estimate you will boil off. If I want to do a 5 gallon (19L) batch, I need a bigger pot. For brews in the 1.050 to 1.065 OG, I can make it work in a 7 1/2 gallon pot (30 quarts, about 28L?) but I have to watch for boil overs.

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