Am I boiling off a lot with a 26% boil-off rate?

[Elysium]

I have just attached an image of my boil. My question is simple: am I boiling it way too strongly? I boil off about 26% (which is 2.3 gallons) of my batch in an hour....shall I lower the strength of the gas burner? I think my boil looks totally ok. It doesnt look look like the boil of other brewers because I have 2 big gas rings at the bottom of my pot.....with loads of small holes. So it is not a focused fire with a single, strong flame....maybe that's the reason why it doesnt seem to be too strong to me and I leave it at maximum strength.

 

[AnOldUR]

% of volume is meaningless. It's gallons per hour that you should be concerned about.

Anywhere from 1 to 2 gallons per hour is acceptable, depending on what you're looking to achieve.

 

[cfonnes]

Altitude and relative humidity affect the rate of boil off?

I start my boil at 12.5 gallons and end up with 10.5.

 

[MaxStout]

Surface area of the kettle will also be a factor. Wide kettles tend to boil off more quickly than tall skinny ones, all else being equal. Mine is the former, 16" wide x 12" deep, and I easily lose 1.5 gallons in a 60 minute boil.

 

[eastoak]

i lose 1.5 gallons in a 60 min boil, need 9 gallons total to get 5 gallons into the fermentor.

 

[AnOldUR]

i lose 1.5 gallons in a 60 min boil, need 9 gallons total to get 5 gallons into the fermentor.

So, you're leaving 2.5 gallons in the kettle? 2 1/2 hour boil?

 

[Toga]

My average boil off is 1.75-2 gallons with my current boil pot. My old tall skinny pot the boil off was closer to 1.25 gallons per hour.

 

[Phunhog]

I get mine to a roiling boil as fast as I can and then turn down the heat until it hits a "low boil". I usually lose about 1.5 gallons during the boil.

 

[Elysium]

I get mine to a roiling boil as fast as I can and then turn down the heat until it hits a "low boil". I usually lose about 1.5 gallons during the boil.

Thanks for the info. If my flame is not a big, focused one (since I have 2 rings with tons of little holes), then how can I tell that I have reached this so-called "low boil"? I dont actually know what a low boil is.

 

[Phunhog]

Thanks for the info. If my flame is not a big, focused one (since I have 2 rings with tons of little holes), then how can I tell that I have reached this so-called "low boil"? I dont actually know what a low boil is.

I just get it to the point where the boiling is not explosive but rather closer to a nice "simmer". The whole point of boiling is a) sanitation and b) isomerization of hop acids but that is temperature dependent.

 

[whitehause]

As stated before % makes no difference. Everyone's system is different and you just need to adjust accordingly.

 

[AnOldUR]

I just get it to the point where the boiling is not explosive but rather closer to a nice "simmer". The whole point of boiling is a) sanitation and b) isomerization of hop acids but that is temperature dependent.

Old but good article.

Importance of a Full Wort Boil

One of the most important reactions that occurs in the wort boil is the formation of "hot break". Hot break is the coagulation of proteins, formation of protein-polyphenol complexes, and reaction with hop compounds to create larger particles that will sediment out in the whirlpool at the end of the boil. These reactions occur at higher rates at higher temperatures and more agitation. This is why your wort boil must be full and rolling... the more vigorous and turbulent the boil, the more of these compounds form over time.