Boil off rate, first kettle use

[Morrey]

I found a heck of a deal on Craigslist for a 20G NIB Blichmann kettle. I'll use this kettle when I do 11G batches and can fill two soda kegs with that batch.

I have used my old faithful 10G Blichmann and can pretty much nail the volumes I'll lose due to grain absorption (BIAB), boil off and other losses. So I figured I'd simply double my volumes going from a 10G kettle to a 20G kettle and from a 5.5G batch to an 11G batch. I used the 20G for the first time on Saturday, over 90F ambient, high humidity.

What surprised me off was my boil rate. I did a 90 minute boil and lost a total of 2.5 gallons of boil off volume in the process. I'm still going to come out ok (barely) when I keg, but I was a bit surprised to boil off 2.5G. I suppose I have greatly increased the surface area of the water with this new kettle, so that's possibly what happened?

 

[dmcman73]

Boil off rate is affected by the size of the kettle, that's why boil off rates are different from brewer to brewer, there is no "standard" boil off rate.

In any event, I have 20 gallon Spike kettles and my boil off rate is a little over 1.50 gallons per 60 min boil, so your 2.5 gallon @ 90 min sounds about right. Are you using propane?

 

[hezagenius]

You can try dialing down the burner a little to see if that helps. I would lose about 1.5g per hour on my 15g kettle. I dialed the boil down a little bit and got it to about 1g per hour.

Or add a little more water at the beginning.

 

[Stillraining]

^ Yep dido.... and if I dont turn my burners down a bit to control such a violent boil I can get 2 gallons boil off in 60 min.

Never mind Hezagenious beat me to it...slow typing got me again.

 

[bruhaha]

I saw the same with my kettles.

 

[Morrey]

Boil off rate is affected by the size of the kettle, that's why boil off rates are different from brewer to brewer, there is no "standard" boil off rate.

In any event, I have 20 gallon Spike kettles and my boil off rate is a little over 1.50 gallons per 60 min boil, so your 2.5 gallon @ 90 min sounds about right. Are you using propane?

Propane, yes. Sounds like I am on target. Learning a new kettle takes a few brews for volume adjustments.

 

[dmcman73]

Propane, yes. Sounds like I am on target. Learning a new kettle takes a few brews for volume adjustments.

As someone else stated, if you want a lower boil off rate, lower the flame.

My system is an all electric.