Massive boil-off question(s)

[altenmuenster]

On this weekend's brew (my 4th all-grain batch, so I'm still dialing it in and hammering out my process) I had a great brew day - it was around 19°, so a bit chilly, but I nailed my mash temps and held it in my coleman cooler MLT without any real trouble. (Batch Sparged)

I ended up with about 6.25G of wort pre boil, so a little less than I was going for, but still not that bad. And I totally forgot to grab a pre-boil reading



After a 60 minute boil I was a bit surprised that I only collected a little over 4 gallons (usually I would be around the 5G mark on this type of boil)

My gravity was 1.061 (expected 1.051 on the Caribou Slobber AG kit that I brewed)

So, in the future, should I plan on more boil off when the temps are this low?

If this had happened to you would you have done anything to "fix" the problem, or just RDWHAHB? (I did the latter)

 

[BobC]

yes, colder the air the drier it is, so as it warms up it absorbs more water.

 

[EdWort]

I add water at the end of the boil. This happened to me several times with the Banjo burner and the Blingmann 20 gallon kettle. The large surface area with a powerful burner and I was boiling off 3 gallons in 90 minutes.

 

[rack04]

I would just roll with it. In my system if I had 6.25 pre-boil I would have ended up with roughly 4.66 gal into the fermenter so I wouldn't classify it as a massive boil-off.

 

[altenmuenster]

Cool - thanks for the replies -- I'll factor in the weather a bit more next time, and as I said, I'm still dialing in the system. Worst case scenario, at the end of the day I have beer, right?

 

[scottatdrake]

Interesting! I learn something every day here.

 

[wickman6]

I've been boiling off a lot more lately too. Should I sparge with more water, or just top up at the end?

 

[Saccharomycetaceae]

I've been running into this problem lately too.
It makes more sense to me to top it off at the end that way I feel like I'm using less propane. (Less water in the kettle=less propane needed to heat it up) I just add small amounts of water, maybe a half-gallon at a time until I reach the gravity I want. Be careful though, I've also added more water than I should've which is pretty frustrating!

 

[Stauffbier]

I think topping up at the end would be a good solution. Especially if your OG ended up higher than expected. Topping up will bring the OG back in line...

 

[Doed]

I just used my new Bayou Classic 62qt pot for my second BIAB on Monday and was a little surprised to see that I boiled off almost 2 gallons on a 60 minute boil. Just have to keep brewing and keep recording notes to dial in my system.

 

[Komodo]

so, who's gonna write the "time and date/latitude longitude/air temperature and humidity boil off calculator"?

 

[Komodo]

oops

 

[waddsworth]

I usually plan for a gallon an hour boil-off and a resulting increase of 1 point. If boil off rate is higher, you can always top off afterwards, before you pitch. It sounds like you would have been spot on with your numbers otherwise.