What is your Boil Off?

[calvey]

I am trying to come up with some meaningful defaults for http://biabcalculator.com. In looking at the Boil Off value I hear some wildly different values. I lose around 1.25 gallons per hour with keg and propane turkey burner.

How much do you boil off per hour and on what kind of setup?

 

[619Brewer]

2 gallons per hour with a 15 gallon BK on a three tier gravity system.

 

[calvey]

619brewer would you say you do a pretty vigorous boil?

 

[robert843]

I brewed last week and lost 1.25 gal per hour. It was 72 degrees and about 75% humidity. I had a rolling boil but would not say it was too vigorous. Single tier brew stand with keggle. The burner looks like a BG 14 with an inner ring.

Sent from my SAMSUNG-SM-N900A using Home Brew mobile app

 

[SpottedDogBrewing]

I found this on the web:

http://sigginet.info/brewing/tools/boil-off-calculator/

& this:

http://www.beersmith.com/help2/index.html?boil_off_tool.htm

Sent from my iPhone using Home Brew

 

[CastleHollow]

^ that's an interesting calculator, SpottedDog--it calculated my boil off on 3 different kettles fairly accurately.

 

[nvious23]

I boil off approximately 1 gallon per hour.

Sent from my SPH-D710 using Home Brew mobile app

 

[camus]

.75 gallons an hour for a 6 gallon boil.

 

[TrevVB]

I just bought a new kettle three days ago and checked my boil rate. It was 1gal/hr


Sent from my iPad using Home Brew

 

[calvey]

Thanks for the replies everyone. .75 to 2 gal/hr is the range so far, with the average being 1'ish.

 

[acidrain]

I would say 1 to 1.5 GPH is the norm... mine is 2 GPH (keggle).
% per hour is not really applicable since you'll boil off the same amount whether it be 6 gallons or 16 gallons boiled in the same kettle.

 

[PRE66_6TART]

I boil off about a gallon per hour, maybe a little less. But I boil 7 gallons on my stove and barely get a boil going.

 

[cjgenever]

Your boil must be rolling. That means a good fluid transfer via convection. It doesn't need to be jumping out of the surface of the wort. Anything over 15% per hour boil off is excessive for most styles. Pretty much anything is going to suffer once you exceed 20%. The reason is you are producing way to many melanoidin compounds. It will define the beer rather than support it. Melanoids are generally unfermentable, so it will affect apparent attenuation as well

Sent from my SCH-R970 using Home Brew mobile app

 

[acidrain]

Your boil must be rolling. That means a good fluid transfer via convection. It doesn't need to be jumping out of the surface of the wort. Anything over 15% per hour boil off is excessive for most styles. Pretty much anything is going to suffer once you exceed 20%. The reason is you are producing way to many melanoidin compounds. It will define the beer rather than support it. Melanoids are generally unfermentable, so it will affect apparent attenuation as well

Sent from my SCH-R970 using Home Brew mobile app

Sorry to hijack. That is really interesting... I hadn't considered that part of it.
So, since my boil off is 2 gallons, and I do 5.5 gal batches, beersmith says that's 21.6%.
The only way to change that is to make bigger batches, or slow down the boil?
That could account for consistently high FG's and an undesirable malty taste.

 

[Qhrumphf]

I boil off about 1.5 gallons doing a 60 minute boil (6.5 to 5 gallons), and about 2 gallons doing a 90 minute boil (7 gallons to 5 gallons). Using two 1500w heat sticks, and a vigorous rolling boil.

 

[Safa]

Sorry to hijack. That is really interesting... I hadn't considered that part of it.

So, since my boil off is 2 gallons, and I do 5.5 gal batches, beersmith says that's 21.6%.

The only way to change that is to make bigger batches, or slow down the boil?

That could account for consistently high FG's and an undesirable malty taste.

Interested to hear the answer to this.

I boil off 1.5g during a 60m boil in a 7.5g pot. I too have been under attenuating.


Sent from my iPhone using Home Brew

 

[acidrain]

cjgenever, I've searched all afternoon and can't find any info supporting your statement.
Can you please site your reference?

 

[brew_ny]

1.5 gallon 60 minute boil 13 gallons down to 11.5 gallons in a 16 gallon pot

S_M

 

[cjgenever]

Sorry to hijack. That is really interesting... I hadn't considered that part of it.
So, since my boil off is 2 gallons, and I do 5.5 gal batches, beersmith says that's 21.6%.
The only way to change that is to make bigger batches, or slow down the boil?
That could account for consistently high FG's and an undesirable malty taste.

If you are doing a 60 min boil then you are definitely boiling too vigorously. Melanoidins often have a malty bready taste in the finished brew. The most common boil off figure is one gallon per hour (most recipes are written with this assumption). I usually keep a low roll and really kick it up in the last ten min to remove DMS. that saves on energy.

Sent from my SCH-R970 using Home Brew mobile app

 

[Hamaki]

If you are doing a 60 min boil then you are definitely boiling too vigorously. Melanoidins often have a malty bready taste in the finished brew. The most common boil off figure is one gallon per hour (most recipes are written with this assumption). I usually keep a low roll and really kick it up in the last ten min to remove DMS. that saves on energy.

Sent from my SCH-R970 using Home Brew mobile app

I'd be interested in the citation as well. When I used propane I boiled off 1 gal/hr. With an electric keggle I'm a bit over 2 gal/hr. I don't think I've noticed a significant difference in finished product but did not save any from the same recipe batches for side by side comparison.

 

[max384]

My boil-off rate is definitely on the higher side, at about 25% per hour... Though this is variable. In the summer (when it is more humid), it is around 20%. In the winter (when it is drier), it is around 30%.

This is the first I've heard of deleterious effects of high boil off rates. The high boil off rates mean that I sparge with a higher volume, which means I extract more sugars during the sparge, which ultimately leads to higher efficiency.

I'd also like to see some sort of references on this claim.

 

[HappiBrew]

In my 9 gal SS kettle with turkey fryer I lose about 1.25 gal an hour. It's got a 14.5" diameter and is about 13.5" tall.

 

[ja09]

I'm also at 2 gal/hr with a 15g megapot from NB (old model). I thought this might be a little excessive, but am not aware of any consequences.

Sent from my SPH-L720 using Home Brew mobile app

 

[HappiBrew]

I found this on the web:

http://sigginet.info/brewing/tools/boil-off-calculator/

& this:

http://www.beersmith.com/help2/index.html?boil_off_tool.htm

Sent from my iPhone using Home Brew

Pretty sweet calculator. Just another handy tool to have. I agree with the other statements about the accuracy. I played around with it and found it to be pretty dead on with all my brew-ware.

 

[Qhrumphf]

If you are doing a 60 min boil then you are definitely boiling too vigorously. Melanoidins often have a malty bready taste in the finished brew. The most common boil off figure is one gallon per hour (most recipes are written with this assumption). I usually keep a low roll and really kick it up in the last ten min to remove DMS. that saves on energy.

Sent from my SCH-R970 using Home Brew mobile app

If he can't provide a citation then I'm calling shenanigans.

Kettle design has as huge impact on boiloff and can be independent of boil strength. Back when I did split boils on the stove, I still struggled to reach rolling boil yet still boiled off 20% due to surface area. I still use a fairly wide kettle. Wider kettle = higher boiloff regardless of anything else.

 

[max384]

I found a citation that supports his claim:

http://homebrewers-haven.com/wpress/how-to-make-beer/melanoidins-101-home-beer-brewers/

The maillard reactions happen in nearly every aspect of brewing, specifically:

Kilning of the grain during the malting process
Drying of the grain during the malting process
Decoction style mashing
Extended boil times
Roaring boil where evaporation rate exceeds 15%

However, I do take issue with this, since boil off rate is largely affected by equipment, not just how heavy the boil is.

 

[Qhrumphf]

I found a citation that supports his claim:

http://homebrewers-haven.com/wpress/how-to-make-beer/melanoidins-101-home-beer-brewers/



However, I do take issue with this, since boil off rate is largely affected by equipment, not just how heavy the boil is.

Along with humidity. And elevation. And wort gravity. And other factors. Boil strength is only one of many factors in boiloff rate. And setting an arbitrary number of "this is how much you should or shouldn't be boiling off" is problematic.

Will a stronger boil increase maillard formation? Sure. However, I question how significant it is. I also question his claim that "anything suffers above 20% boiloff and you're boiling too vigorously". That's taking leaps of logic that don't include the other factors above.

 

[Grannyknot]

I'm calling bunk on the "excessive boil off rate".
I have a very wide kettle, boil off 2.25 gal per hour.
Get great hot break, great attenuation, & many awards.

 

[Beer-lord]

It's pretty humid in my area so in the summer, I get about 1.25 per hour in my 15 gallon kettle but in the winter its about 1.5 or a bit more.
I use this BIAB calculator and set mine to 1.3 and its worked pretty good for me and my equipment.

 

[Hello]

I found this on the web:

http://sigginet.info/brewing/tools/boil-off-calculator/

& this:

http://www.beersmith.com/help2/index.html?boil_off_tool.htm

Sent from my iPhone using Home Brew

Hmmm it gave me 1.85 gph. Not sure I've seen that yet. I am still trying to dial in my kettle and such but I thought last time I lost just under 1.5 but maybe I am wrong and therein lies some of my issues.

My kettle is 1.00mm thick and 18" in diameter. I use propane.