Boil time not affecting OG

[snails07]

I have my equipment profiles all set up and dialled in.

On the recipe builder, changing the value in the Boil Time field is not changing the OG value.

A 1 minute boil time should give an OG virtually the same as the pre-boil gravity and a 120 minute boil should markedly increase the OG, but it never changes.

What am I missing here?

 

[BOB357]

My guess is that the recipe builder adds water to the sparge to compensate for the greater boil off. Not that familiar with BF, but the software I've been using for years does that.

 

[jeffpn]

Yeah, I think that’s for the water calc, and not the recipe.

 

[Hobbes]

The issue is the "kettle" or "fermenter" volume is not calculated rather it's user input... as far as I can tell. So if you change the boil time it's assuming that you put the correct value for the "boil size" and "kettle/ferm" volumes. If you change boil time i'm not sure if anything else actually uses that value to determine something... maybe first wort hop since it'd be in the boil the whole time.

Ideally, you'd change boil time and either the pre-boil vol would get bigger as well as the sparge/mash vols to compensate or the ending kettle volume would shrink. And both should be a function of your equipment boil off rate. I'm not sure if i'm using it wrong either or if BF just isn't there yet.

 

[oliver]

the recipe editor doesn't care how long you boil in terms of gravity. it just cares about boil off amount to calculate OG.

changing the boil time in the editor only affects IBUs, as it should. 5 min or 50 min boil result in different IBUs.

Make sure you know you're boil off rate on your setup. In 60 min I typically boil off 3 quarts, so I know to put my boil size as 3 gallon and my ending kettle as 2.25 gallon. my ending fermenter value is different because I typically pitch a 1 liter starter on it, raising my fermenter target to ~2.5 gallon, and I compensate it with a late addition value of DME in the recipe. The editor is reading my recipe as going 3 -> 2.25. And speaking strictly in terms of gravity, it doesn't care how fast you boil off all that amount, it only cares where you're starting your boil and where you're ending your boil, and not when you're starting and ending.

now obviously boiling for 1 min and 120 min will actually affect your OG, but you still need to know your boil off rate and adjust.

If I set my boil size to 3 gallons and I set the boil time to 1 min, I would need to set my ending kettle to 3 gallons, because that's no time to boil anything off.

If I set my boil size to 3 gallons and I set the boil time to 120 min, I would need to set my ending kettle to 1.5 gallons, because I typically boil .75 gallons per hour.

 

[snails07]

Thanks for the explanations, it makes more sense now.