How much evaporation do you get?

[DyerNeedOfBeer]

I usually boil 10 mins prior to starting my hop adds and typical 60 minute timer (total boil of 70min). I have been losing about 2 to 2.25 gallons during this time. Has anyone else had these high evaporation rates?
I do extract and steep the grains in 5 gal of water followed by a 1gal sparge. I am wondering if I may be losing a bit of water due to the grains soaking up water. I may also be losing some from the leaf hops which I leave behind in the brew pot. I have a typical turkey fryer so the rolling boil is nothing excessive. It has been in the upper 90's here with humidity in the mid 60's to mid 70's.
I plan on starting my next batch with 7 gallons and a target wort of 5 gal.
I just got pro mash software to play with and find that they estimate about 16% loss where I am about double that to evaporation (or whatever a combination of things it may be)

 

[DeRoux's Broux]

i usually lose 1 to 1.5 gallons in my boil (75 minutes). i boil for 15 before starting my hope additions. i utilize a vigorous boil too. grains will retain water from the mash.
go to www.allaboutbeer.com and click the homebrew menu on the right. do a search for brewing water. ray daniels has an article and formula for figuring you water needs. it may not apply to grain/extract brew, but still a good read.

 

[SwAMi75]

Yes, all the things you listed will decrease your volume. Guessing how much you're going to boil off is tricky. Basically, the more humid it is, the less you'll boil off, and vice versa. I don't think there's anyone who can nail their volume perfectly every time.

 

[Sir Sudster]

All I can think of is that your burner must be jet powered. 200K+ BTU's
and your rolling the boil at its max rate. I do not know the science but I am trying to apply practical logic to your problem. Seems your dew point is at max saturation so the double boil off can only mean to me that the you have very high efficency in your kettle. Turn the boil down a bit ..keep it rolling but not raging especially with your heat and humidity factor. I use 15% in Promash and I am usually pretty close. When the humidity and temperature drop I will have to adjust upward. The last time I brewed it was 95Deg F and 78% Humidity and I used 15% and came real close. Maybe someone out there has a correlation factor we could use with Dew point and altitude to determine our exact boil offs.

 

[tnlandsailor]

I use a 50 liter turkey fryer for my 6 gallon batches and boil off a consistent 1.5 gallons per hour. The key to nailing your boil off rates is to track your volume during the boil. For this reason, I think every kettle needs a calibrated sight glass. I monitor the volume using my sight glass and boil off 0.5 gallons every 20 minutes. By monitoring the volume via a sight glass, you can adjust your burner intensity to keep a uniform and linear boil-off rate regardless of batch size or ambient conditions. Check the Vendor Showcase on this Forum.

Boiling off 2 to 2.5 gallons sounds pretty excessive. In order for me to boil off 1.5 gallons per hour, I keep a very vigorous boil going. If I try to boil more than this, the boil is usually so vigorous that the hops get deposited on the side of the kettle above the boil line and I have to stir them back in. I think a vigorous boil that does not deposit hops on the side of the kettle is the correct boil intensity.

I think judging boil off as a percentage for homebrewing is not accurate. Regardless of your batch size, if you use the same kettle, you should get the same total amount of evaporation for the same amount of time whether you are boiling 5 gallons or 10 gallons. Go into your Promash options and change the default measurement in Mash System/Evaporation for boil off to "gallons per hour" instead of "percent per hour".

 

[DyerNeedOfBeer]

After playing with pro-mash and one of the links someone left above, I believe almost one gallon of what I am losing is due to the steeping of grains. I had not considered this to be such a large factor but apparently it is much more so than I had thought. Thanks for all the input!

 

[Turricaine]

Personally my boiler is a five gallon polypropylene vessel with a heating element similar to those found in kettles. It takes almost a full hour to break into a decent boil so certainly no problems going on here with excess evaporation. I lose a few pints due but nothing majorly drastic.

 

[Janx]

My initial boil volume is ~14-15 gallons and I end up with ~12-13 or so after an hour boil.

 

[DeRoux's Broux]

My initial boil volume is ~14-15 gallons and I end up with ~12-13 or so after an hour boil.

yep, our 15 gallon brew saturday ended up w/ 13.5. we just added 1 gallon of distilled water to each carboy to give us 5.5.

 

[Dude]

My initial boil volume is ~14-15 gallons and I end up with ~12-13 or so after an hour boil.

Janx, you don't do 90 minute boils with your batches?

This is a great thread. I'm having the exact problems. In fact the brewmaster at St. George brewery wants me to come up with a chart for him to figure volume at the brewery as well.
I'll start working on this soon. I'll post the chart when I get it done!

 

[Janx]

I sometimes boil for 90 minutes, but usually an hour.

 

[Dude]

I sometimes boil for 90 minutes, but usually an hour.

I'm hoping this isn't hijacking the thread, but "adding" to it.....

But...is there a reason? Is it just time constraints? Do you notice a difference with a longer boil?

 

[Janx]

I imagine you'd get greater hop utilization in a 90 minute boil. For some of my higher gravity beers, I go with a longer boil for that reason, but normally I'd rather not waste the time or the propane.

How long do you boil normally?

 

[DeRoux's Broux]

longer boils help w/ hop utilization and clearer brew (helps coagulate protiens). i do a 75 min or 60 min boil. also helps to get rid of unwanted chem's in the water like chlorine. that's why i usually do a 75 min boil. start doing hop additions after the first 15. now that i have a 15.5 g brew kettle, i may start doing 90 min boils?

 

[Janx]

That makes sense. I have very clean spring water so chemical content isn't a factor, but if I had chlorinated water I'd definitely want to boil it off. Hot break is another good point.

As for hop utilization, I guess I've never felt it lacking, but I do like to give it some more time with bigger beers because higher gravity inhibits hop utilization.

A lot of folks do seem to boil longer than 60 minutes. I've just never felt much of a need in my brewing, and I'm lazy It's probably a better idea to go ahead and boil longer and I don't think there are any ill effects to a somewhat longer boil.

Cheers

 

[Dude]

I imagine you'd get greater hop utilization in a 90 minute boil. For some of my higher gravity beers, I go with a longer boil for that reason, but normally I'd rather not waste the time or the propane.

How long do you boil normally?

Since I went AG I started doing 90 minute boils but I don't know why. All I ever read was just to do it. I never thought it made sense just to boil the wort for 90 minutes. I don't even add hops until 60 mins on most of the recipes so it seems pointless to me to boil that long. I thought it had something to do with SG or something. Honestly, I don't think I'm going to bother anymore.

And I'm ditching my hydrometer too. All it does is give me extra worry that I don't need.

 

[Born Brewing Co.]

Hey, Orrelse. The Clone Brews book calls for a 90 minute boils on all recipes. Other books I've read say that 60 minute boils will suffice. Are there advantages to longer boils. As always, Thanks!

 

[Janx]

Well, to sum up the 4 or 5 posts above yours. Longer boils advantages:
more thorough hop utilization
boil off chemicals
more thorough hot break

Cheers

 

[uglygoat]

i try and let it boil for 15 min before i put any hops in there... but the last two batches i've only boiled for 60 min cause i'm down to the bottom of my propane tank, and didn't want to run out in the middle of the boil...

 

[Janx]

Yeah it *really* sucks to see that flame fizzle out in the middle of a brew session. It's happened to me for sure.

 

[bikebryan]

Yeah it *really* sucks to see that flame fizzle out in the middle of a brew session. It's happened to me for sure.

That's why I have two tanks, one hooked to my grill (not used all that much) and one for brewing. The one time the brew tank ran dry, I quickly switched tanks, then refilled the empty the next day.

 

[El Pistolero]

That's why I have two tanks, one hooked to my grill (not used all that much) and one for brewing. The one time the brew tank ran dry, I quickly switched tanks, then refilled the empty the next day.

Yes, I have to say that as much as you guys seem like total beer brewing gods to me, this plebe can't hardly believe that you don't have at least one spare tank ready to go when the first runs out.

 

[Dude]

(She's a) Sweet Little Heifer Weissen

LOL...that's awesome....

 

[Janx]

Yes, I have to say that as much as you guys seem like total beer brewing gods to me, this plebe can't hardly believe that you don't have at least one spare tank ready to go when the first runs out.

Well I have three tanks used only for brewing.

Yeah, I let em all run out! You saying I'm a slacker??