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FishinDave07 · 09-21-2008, 03:05 PM

I lose 2 gallons in a 60 min boil

Is that normal with a 15.5 gallon keggle?!

My burner is this one, from Bass Pro shops. I run it extremely low; just enough to get a good boil.

Thoughts?

beretta · 09-21-2008, 03:28 PM

I don't have a keggle, but I loose 80% on my 5 gallon batches. I start with 6.5 gals and end up with 5.25 gals, after an hour. So you loosing 2 gallons, seems realistic.

**rabidgerbil** · 09-21-2008, 03:33 PM

Quote:

Originally Posted by beretta

I don't have a keggle, but I loose 80% on my 5 gallon batches. I start with 6.5 gals and end up with 5.25 gals, after an hour. So you loosing 2 gallons, seems realistic.

Correction, you lose 20% and retain 80%. If you LOST 80%, you would only have 1.3 gallons left at the end of your boil.

Evaporation percent = 100 - (post-boil volume x 100 ÷ pre-boil volume).

From BYO

Most commercial brewers want to evaporate at least 8 percent of the wort volume during boiling to ensure adequate removal of volatiles, such as dimethyl sulfide. Excessive evaporation can result in the formation of unwanted flavors. It also wastes energy. Energy is not a huge concern with homebrewing, but imagine a commercial brewkettle with a pre-boil volume of 800 barrels (24,800 gallons). A typical boil can evaporate 64 barrels (1,984 gallons) of water in 60 minutes! That requires a lot of energy...

Most commercial brewers target between 8 and 10 percent evaporation during the boil. For homebrewers, a good evaporation rate is 6 to 8 percent per hour. A kettle that evaporates 6 percent per hour will evaporate 8 percent of the volume in 80 minutes. If another kettle evaporates 8 percent per hour, then a 60-minute boil will evaporate the same wort volume.

**ajf** · 09-21-2008, 03:41 PM

I lost over 2 gallons yesterday with a 5g batch (started with slighly over 6.75g, ended with 4.75), but it wasn't all evaporation. Shrinkage during cooling, hop absorption (5 1/2 oz whole hops), and wort left in the kettle and chiller all contributed.

-a.

FishinDave07 · 09-21-2008, 03:55 PM

Quote:

Originally Posted by ajf

I lost over 2 gallons yesterday with a 5g batch (started with slighly over 6.75g, ended with 4.75), but it wasn't all evaporation. Shrinkage during cooling, hop absorption (5 1/2 oz whole hops), and wort left in the kettle and chiller all contributed.

-a.

I know shrinkage affects the final volume, but THAT much? i only used 2 oz of whole hops, and this time siphoned practically everything into the fermentor. I use a IC as well.

**Jaybird** · 09-21-2008, 04:16 PM

I use a keggle and I always boil off 2 gallons in 60 min and 3 gallons for a 90 min boil.
Cheers
JJ

issack · 09-21-2008, 04:28 PM

you don't add liquid from your mash.? I add as i boil from my mash ton that i batched sparged in. I get 14 gallons clean every time from my Keggle.

Blender · 09-21-2008, 04:33 PM

I start with 8 gallons and end with 5.5. I do about 75 minute boils.

beretta · 09-21-2008, 11:00 PM

Quote:

Originally Posted by rabidgerbil

Correction, you lose 20% and retain 80%. If you LOST 80%, you would only have 1.3 gallons left at the end of your boil.

Tuche'. Sorry, I was thinking backwards this morning. 80% / 1.3 gallons sounds like I'd be making my own canned extract!

farmbrewernw · 09-22-2008, 12:50 AM

I loose 2 gallons with my keggle, I had been figuring 1 gal for a while and last winter that worked but my last couple of batches I have been boiling more like 2 gallons leading to some higher gravity brews than I wanted.