Boil off rate?

I posted this in another section maybe this section was more appropriate. I just did a water only boil to check my boil off rate on my new 15 gallon Polarware. All I gotta say is Holy Boil Off Batman!!! 3 gallons in 90 min. Is this normal? I was expecting 1.5 to 2 gallons but 3, wow. Please tell me this is normal.

Thanks, Tim

Not sure if its normal or not. But, I burn off a gallon per 1/2 hour. Same.

Well at least we are at the same rate. I guess I will just get used to it.

That's about normal especially if it is a wide kettle with a lot of surface area as well as dry air, when it is more humid out it may lower a bit, you can also reduce the boil a bit with less vigor.

Gotta boil vigorously. Using Pilsner malt. Yep the Polarware 15 gallon is pretty wide. I didn't think it would make that much of a difference.


Thanks for the replies, Tim

Tim27 said:

Well at least we are at the same rate. I guess I will just get used to it.

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Thats the key. As long as it is consistant (or at least sorta consistant, like Duboman said, the seasons are a changin), you can plan your brew day and make great beer!!

I guess I gotta buy some more water, a full 10 gallons. The water here is unsuitable for brewing so I gotta go bottled.

I boil in a similar 15g pot. I limit my boil loss to about 1 gal/hr. The wort surface is moving fairly good, but I don't let it really erupt or boil real hard. Its not necessary to boil that hard. You just want the wort to have a definite circulation so that hops, proteins, and the full volume of wort is brought to the surface regularly. I do make sure that the wort movement shows this.

I gotta ask this question then....is the boil off rate the same for just water as it would be for wort, especially a high gravity wort? Does sg affect the boil rate at all? Just asking is all.

My boil didn't seem to be all that vigorous, I guess it was. It will be interesting to see if the boil off is different when it is wort and not water. I don't think it will change the boil off.

I've found that I can reduce heat after the initial boil and still get a pretty vigourous boil with a far lower boil off. That little trick ended up reducing my boiloff by nearly 30%

Wort or water, I don't think it matters. There are ways to reduce the boil off rate, but unless you don't have enough room in the pot, there's no other reason to worry about it. It doesn't effect the quality of the beer. Just like efficiency, consistency is what you are looking for. Learn your system and then you can duplicate any recipe.

Thanks for the help guys.

I have an extremely narrow and tall 8 gallon kettle, and I only boil off a gallon an hour. Kettle geometry really does make a big difference. Compensating for it is all you need to do, though.

In a regular 60 minute boil, I go from 6.5 gal. in my 7.5 gal pot down to 5+ gal., about the right amount. I do not do a vigorous, "rolling" boil. I achieve a bubbling boil and that's where it stays. I regard the "volcanic boil" as a waste of propane.

A "rolling boil" is just that, the surface appears to be rolling over. Vigorous boiling with lots of splashes and bubbles bursting is not necessary. If you can control the boil so that it appears the same with each batch then you should be able to predict your boil off rate somewhat. The humidity and air temperature will play a part, as will air movement over the pot, either from the wind or a fan. When I pay attention to the humidity level I have found that I can maintain a consistent boil off level fairly easily.

There is some difference in boil off rate between water and wort, but I think that it is mainly due to the higher temperature that it takes to boil wort.

.75 gallons per half hour in keggle

1.0 gallon per half hour in megapot


3 gallons over 90 minutes is normal. Increase preboil volume next time. Its actually kind of helpful in that you get to use more sparge water ......

ron said:

I gotta ask this question then....is the boil off rate the same for just water as it would be for wort, especially a high gravity wort? Does sg affect the boil rate at all? Just asking is all.

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I set the PWM on my eKeggle for a 15% boil off rate using water (1/2 gallon per half-hour). I found it to be the same boiling wort as far as I can tell.

I'm quite certain Jamil has said more than 15% boil off rate is either unnecessary or not the greatest. I'm having a hard time going from memory on this one.