Started my boil with about 6 gal, ended up with 2.33 gal

Was I boiling to vigorously? I stepped away for most of the boil but didn't think I could boil off almost 4 gal of wort. I am using a SQ14 and keggle for my full boils. This is my second brew ever and on the first one I boiled over in a keggle. I guess I am just turning it up to high? Any tips on getting a boil and then turning it down?

I ended up topping off my brew with about 2.5 gal of bottled water to get it down to my target OG. 2.5 gal brought it down from 1.101 to 1.049. I also just looked at my notes and saw that preboil was 1.063 which seems high for preboil. The only thing I can think of is that I didn't mix the sparge water in well enough before taking a reading? I also sparged with 190* water. It was a quickly put together brew and BeerSmith spit out some funky numbers. I tried to change it but wasn't getting any different data so I went with it.

I checked on the beer last night and its bubbling away in the fermenter so we'll just see how this turns out.

 

Yikes! How long did you boil the wort for? 2 hours?

 

I just don't see how it's possible to boil off that much in an hour. I have a pretty wide brew kettle and even that one with a vigorous boil does 1.5/hr.

It sounds like you said you might have boiled over? Boiling over 6 gallons in a keggle sounds really hard to do, it would have to like tripple in volume.

 

i'm guessing you really started with 4 gallons. how did you measure preboil volume?

 

Did you account for water that was trapped in the grains? What goes into the mash is not what comes out of the mash.

 

Sounds like a miscalculation and or boiled in hot lava. Thats insane!!!

 

Maybe if he/she was at a really high altitude, in the desert, with a very wide flat brewpot and a strong fan blowing over it? heh...

 

Good news the DMS is gone!

 

I initially doughed in with 3.5 gal and sparged with another 3 gal. So I probably only collected 5 gal or so. I had it going real good that the hot break was up to to the top of the keggle. That is when I turned it down. I did not have a boil over (although on my first brew, I did boil over 5 gal in a keggle, but still ended up with 4 gal at my target OG). I live in WI and I'm at a normal altitude. I think I had the boil to high. Like I said, I kind of walked away from it and came back to a keggle full of hot break. Flames were not coming out the sides of the keggle though.

I was focused on everything but the boil since my parents came over to the house and we were working on some stuff (unplanned).

 

Maybe if your boil kettle was a sheet pan, and your heat source was satan's icehole, then you could possibly boil off 60 percent of your batch in an hour.

 

Omg I can't stop laughing at this.

 

I'm pretty sure the temperature of the burner really doesn't matter. Water boils at 212F (at sea level) no matter how hot your burner is.

I maintain that if you had a very flat brewpot and a strong fan blowing over it, you might be able to pull this off. I regularly reduce sauces by about 50% in something on the order of 20 minutes, but the pan I do it in looks like this:



And if it was filled more than halfway, you aren't going to reduce it nearly that fast.

In any case, I was mostly joking, because clearly that's not what happened.

OP, you say you weren't paying attention to the boil... but you are sure it was only an hour, right?

 

Yeah, but the rate at which you turn water at 212 into steam at 212 is directly correlated to amount of heat input, which is a function of burner size and temp. So burner temp does matter.

 

if you're putting more energy in, you're gonna get more vapor driven off. the temp of the liquid water will maintain roughly 212F sure, but that extra energy will go toward driving off more vapor.

3.5 gal mash, so roughly 11 pounds of grain?

11*.14 = 1.54 gallons absorbed

3.5-1.54+3 = 5 gal max, less mash tun dead space, etc.

 

Sorry guys, but I'm just not buying it. It matters up to a point, but after that point, the water is going to be undergoing phase transition at pretty much the maximum possible rate given the surface area exposed to air.

If you kept heating it until the bottom was vaporizing, I guess you could have this happen, but with your whole pot instead of just a few drops.

I don't know, I could be wrong on this point. There is definitely a point of diminishing returns, and I am thinking that once you get to the point of a vigorous rolling boil, you're essentially going to get no increase in evaporation rate even at higher burner temperatures. I think.

 

Yeah, it was 10 lbs of grain. So I collected about 5 gal, not 6. Still boiled off a little more than half of the liquid. Oh well, I diluted to my OG, we'll see how it turns out. Hope its not a dumper.

 

Okay, maybe you guys are right after all, although I am still thinking that you're going to get to a point where the increase in boiling rate is very small.

I'm asking myself, where is the energy going? There's no way that it being at a boil means that you can't possibly put more energy into the wort, so it's not like it will magically start being diverted to the pot sides or the surrounding air just because it's boiling.

I do think that once the whole pot is at boiling from top to bottom, the wort is going to start self-insulating from the bubbles of water vapor that will be present. The faster your boil, the more water vapor; the more water vapor, the more insulation; and the more insulation, the harder it will be to get any more effect from increasing the heat.

I have yet to find any scientific thermodynamics info on "Satan's icehole," so I cannot speak to whether this would increase your boil rate enough to produce the effect seen by the OP.

 

Just from a thought experiment perspecitve, think about what would happen if you could chuck a 6 gallon brew pot at the surface of the sun. Pretty sure nothing would be left after an hour. :-D

 

heh, I actually had done that thought experiment already even when I was arguing for no effect from increased temperature. But that is not comparable, because the brewpot would be melted, thereby increasing the surface area exposed to the heat source, and then all bets are off.

A better thought experiment would be to imagine some "magic" solid that can heat up indefinitely but will never undergo phase transition. In fact, it also won't expand or contract. It is static and unchanging, except for temperature. (Ignore the fact that quantum effects would make this not just impossible, but impossible to even visualize; we are operating at a macroscopic thermodynamics level here and we can ignore quantum degeneracy and such) You make your brewpot out of that, and it is an infinitely tall brewpot. THEN you chuck the brewpot (bottom side first) into the sun -- what happens then?

The reason this is a better thought experiment is because at the temperatures we are talking about, the brewpot essentially behaves like the "magic" material that can never melt or expand. Your brewpot isn't going to melt, and even at very high burner temps the expansion is trivial in terms of the effect we are visualizing.

So does the wort still vaporize instantly? Well yeah, probably. Sort of. You'd have to chuck at the sun really freakin' fast, because at ordinary speeds, what would happen I think is that the water in the bottom of the brewpot would vaporize instantaneously, propelling most of the wort towards the "top" of your infinitely tall magic brewpot at very high speed.

This is relevant because I think something kind of similar would happen as you are increasing your burner temp in a real world scenario. If the water in the bottom of the brewpot is undergoing phase transition, then less of the wort's surface area is exposed to the bottom the pan due to bubbles of water vapor interceding.

 

This is what a good boil should look like:

 

+1

 

I mash with 5 gal., and sparge with a bit over 3 gallons. I also use an SQ14, with a pretty cheap 30 qt. SS pot. I achieve a good bubbling boil and leave it at that. I will usually get a good 6.5 gal. of wort, and end up with around 5.25. I can only conclude that you're boiling way too hard.