Water Volume

[Anthony P]

A few days ago I brewed a 5-gallon BIAB batch, used 7.75 gallons of water, based off a 60 min 1.25/Hour boil off rate, .25 trub, and a .045 per gallon grain absorption rate. I ended up with a little over 5.5 gallons in the Carboy; planned OG was 1.064, I had 30.7 PPG with an efficiency of 83% and OG of 1.067 with an extra .5 gallons using 11lbs of Pale 2-Row and 1Lb Crystal 40.


A couple days ago I did an extract DIPA (same beer just BIAB vs Extract, wanted to see which turned out better), I figured the same boil off rate + 20 min steeping, I cut that in half to .2 gallons, trub number but took out the grain absorption rate and started with around 7.5 gallons, 20 min specialty grains steep, 60 min boil, 9 lbs malt extract, planned OG of 1.064, I ended up with just over 4 gallons at OG 1.052.


I just did another with 9lbs malt extract + .75lbs grain steep, I used 8 gallons to start, I just added in the grain absorption rate and ended up with around 5.75 gallons at 1.062; target was 1.065.


It’s been hot and windy here in Kansas, 90’s; I have enough LME for one more batch and I just can’t figure out what I’m not taking into consideration with extract; any ideas would be appreciated.


I use a 26 gallon Kettle, (19.75”x19.75) and propane.

 

[RM-MN]

With extract the sugars are guaranteed so your OG will be as specified if your volume is correct. If you added top off water as many of the kit suggest, getting a good mix for taking the OG is difficult and the measured OG can be close or far off.

 

[myndflyte]

This^. You don't need to do a full volume boil with extract. Just undershoot it and then top off to where you need it to be.

 

[isomerization]

If I’m reading your 2nd paragraph right, you boiled off 3.5 gal in one hour! Perhaps one of your volume measurements was off?

I will echo the other posts, with LME, mixing of the wort is critical to an accurate reading, which is easier said than done.

 

[ancientmariner52]

A 5 gallon batch in a 26 gallon kettle 20" in diameter? Your boil off rate will be through the roof on account of the huge surface area in relation to depth. Just as a shallow puddle dries up faster than a deep one. If you can't use a smaller diameter kettle, try to keep the boil as low as possible. A rolling boil isn't neccesary, and in this case will be a bad idea.