Way too much boil off

[Clonefan94]

I use the calculators on brewersfriend.com. I also measure boil off in gallons per hour. Using a percent evaporation isn't very accurate. The amount you boil off doesn't depend on the total volume, it goes at a constant rate. My boil off is about 1.5 gallons/hour. If I boil 6.5 gallons of wort for 1 hour I end up with 5 gallons which is 23% boil off. But if I boil 4 gallons for 1 hour I end up with 2.5 gallons which is 38% boil off. The amount boiled off is the same but the percentages are drastically different.

Great post. I never understood why calculators even use a % for boil off. No matter how much water I have in my pot, I boil off 2 gallons per hour. Seems strange to have a percent when that will change with the amount of wort.


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[JoeSpartaNJ]

I brewed again today. I went back to my old burner and moved it back in the garage, used the same 15 gallon pot, and increased my calculated evaporation to 20%. I am happy to say that my final volume was a calculated 5.5 gallons and had about 1/2 gallon of hot break left in the pot.

Thanks everyone on the guidance.