Overestimated boil off with a full boil

[29thfloor]

I just did a Belgian Quadrupel that was supposed to have an OG of 1.104 but I overestimated the boil off and still had a little over 5.5 gal after the boil. OG corrected for temp was still only 1.084.

That's pretty far off from the target but still relatively high so I'm guessing it'll still be ok? Obviously it'll be different than the recipe but hopefully still good.

Is there anything else you can really do at that point? Does it make sense to get it back up to a boil again and try to boil off more? I would end up doing about a 120min boil in that case.

 

[29thfloor]

Blow off hose is bubbling away after just 3 hours. Feeling better already...

 

[brian74]

For future reference, you could have kept boiling until desired OG was reached. You will still have good beer though.

 

[cincybrewer]

For future reference, you could have kept boiling until desired OG was reached. You will still have good beer though.

wouldn't that vastly change your hop additions though?

 

[broadbill]

wouldn't that vastly change your hop additions though?

yep, especially if you had some sort of flavor addition that ended up being boiled for longer than it should have.

How did you miss your volume brewing extract?

 

[cincybrewer]

I can't speak for 29thfloor but when brewing full boil it is pretty easy to miss your volume depending on the boil-off rate.

 

[29thfloor]

Yeah for some reason when I decided to start doing full boils I looked into what the pre-boil volume should be and read a couple different things that the average seemed to be about 1 gal per hour so I just went with that (starting with 6 gal for a 5 gal batch). I'm not sure why I didn't give it more thought.

I've done 3 so far. With the first two I think much closer to a gallon boiled off because the OG was only off by a couple points. For this one I actually steeped the grains in 2 gallons in a smaller pot while heating the other 4 gal in the main boil kettle and then combined them for the actual boil. I figured the evaporation rate while getting up to a boil wouldn't make much difference but maybe that's why this one was so far off?

Either way I think next time I'll just start with 5.5 gal (or even a bit less) and just top off if I have to. I'd rather top off a half gallon and hit the target OG than end up with too much.

How do you normally take a gravity reading during the boil? I usually wait until it's down below 100F and then just correct from there. I guess I would just take a sample and throw it in the freezer for a few minutes to get the temp down a bit?

For this particular beer (Belgian Quad) there was just a 1/2 oz flavor addition at 15 minutes so I could have checked the gravity then held off on that addition until I got more boiled off?

 

[aomagman78]

I'm pretty sure humidity would have a large affect on the boil-off. I'm in AZ where humidity is 10%, I'm going to get a lot more than if it were 50% on the east coast. If your stove or burner setting is consistent, this should be the only significant factor, possibly ambient temperature as well. So take note and plan for next time.