Beer Forum

So, I boiled some water in my kettle to figure out a definitive number for an evap rate and got some crazy ass number like 40%. My set up is a turkey fryer burner and a converted half barrel keg. I feel the number is right, but I'm just concerned with whether or not this much evaporation is negative to my brew. I know I could just turn down the burner but I like to just crank it up all the way every time. That way it is repeatable every time.

I haven't noticed any negative effects, but then again I've always brewed on that setup, and I'm no "Golden Pallet" Rossi. So, I may be caramelizing everything I brew and just don't know it.

Do any of you think this number is just too much? Am I caramelizing the hell out of my wort? What kind of numbers do you all get typically?

That is too much!
You will get wicked carmalization.... once you get it roaring turn it down to the point where it is just nice and bubbly where stuff is swirling... I will probably be different with wort tho because of the sugars.
BUB

Some of it could be the ambient temp and humidity.

Since it has gotten bitter cold and very dry I have noticed that my evaporation rate has dramatically increased but not to 40%.
That is very high.

Another thing you will want to do is base your evaporation rate on volume/hour rather than %/hour. The % will vary with the amount of liquid in your kettle while the volume/hour rate will remain pretty stable (varying primarily with how high you turn up the flame)

Most people seem to get a boil off rate between 1 and 1.5 gallons per hour.

If you start with 6 gallons preboil, do a 1 hour boil and end up with 5 gallons, your % boiloff rate is abut 17% or 1 gallon per hour.

If you start with 2.5 gallons and boil for 1 hour in the same pot, you will end up with 1.5 gallons. That's the same 1 gallon per hour, but a whopping 40% boiloff rate!

This might be the source of your excessively high boiloff rate. Also you are up there at a much higher altitude there in Boulder where the air is much drier that what most of us have. This will tend to give you higher evaporation rates. The sugars in the wort may also play a factor.

I keep my boil at a good strong rolling boil as opposed to what I would term a violent boil where water is splashing out of the pot. I think you should go back and recheck your volume boiloff. If it is much above 1.5 gallons/hour then you will need to cut your gas back a bit to avoid carmelization.

Wayne
Bugeater Brewing Company

Thanks for the comments guys.

After I wrote the post I started thinking along the lines of what Bugeater was saying. I only boiled 5 gals and ended w/ 3. So, That is a bit over 1.5 gal/hr but it seems a hell of allot better than 40%. I normally boil down from somewhere around 7.5 or 8 to 5.5 and that is more like 27%, which still seems a bit high, but I'm ok with that for now. Now that I know, I'll stick w/ the 2 gal/hr until I figure out how to reproduce my boil each time by looking at it. Just another excuse to brew more right?

Thanks again for the help guys

I took a quick video of my wort boiling a few brew sessions again. I would call this Vigarously boiling. Everything is turning and moving around. I'm not sure that some of you could call it that though.

http://www.brotherhoodbrew.com/vigorously_boiling_wort

That's pretty much what mine looks like when it is rolling along.

Looks like you had a pretty good boilover that day? That will mess with your volume measurements, fo sho!

That's awesome Brotherhood,

Mine is going a bit harder than that, not much though.

I guess really what I'm lacking is a good visual sense of what other folks are doing. That helps alot, Thanks again.