2gl Extract full boil, boil off amount.

[venquessa]

Is there an easy way to judge/calculate how much wort I will lose with a 30min steep and a 30min boil aiming for 2 gallons of wort at the end?

 

[KoedBrew]

It is hard to be exactly sure unless you and your system in certain conditions have done it before. I usually get about a 1 - 1.25 gallons an hour for a normal boil. Could be more for a rigorous boil. For what you are asking I would say about 3/4 a gallon? Just a guess though

 

[BamaRooster]

It is hard to be exactly sure unless you and your system in certain conditions have done it before. I usually get about a 1 - 1.25 gallons an hour for a normal boil. Could be more for a rigorous boil. For what you are asking I would say about 3/4 a gallon? Just a guess though

I also get about 1 - 1.25 gallons of boil loss per hour. You could do an experiment, put 3 gallons on the boil and then measure it after 1 hour and you'll have an answer.

 

[ajf]

I also get about 1 - 1.25 gallons of boil loss per hour. You could do an experiment, put 3 gallons on the boil and then measure it after 1 hour and you'll have an answer.

+1.

Boil 3 gallons of water for an hour and see how much you have left. Best way to judge how much you boiled off is by weight as hot water has a higher volume than it would when cooled.

-a.

 

[frankstoneline]

If you've boiled in your pot before changing the volume or time shouldnt change the boil off rate so you should lose half as much as you would expect in a 60 minute boil.
As for the grain loss its ~0.125 gallons/lb (this changes a little depending on crush, whether you squeeze drain etc).

 

[ajf]

If you've boiled in your pot before changing the volume or time shouldnt change the boil off rate so you should lose half as much as you would expect in a 60 minute boil.
As for the grain loss its ~0.125 gallons/lb (this changes a little depending on crush, whether you squeeze drain etc).

That's true if you express the boil off rate as gallons per hour, but not if you express it as a percentage.

-a.

 

[venquessa]

Well I stuck into the brew last night without even looking on the thread. For one I realised I had no way of measuring how much water was in the pot, except to fill it with 2 5 litre demijohns worth. I filled the demi johns to the very top, which pretty much maxed out my 12.5 litre boil pot.

I was careful with how much sparge water I used, judging by eye that I had slightly less wort than water I started with and luckily(?) came up with 2 demi johns full of wort and only 1 inch above the shoulder where it starts to narrow.

Trouble is... I was drinking home brew and by the time I finished, as it took so fricking long for my stove to boil the water... I was a little drunk. I forgot an OG measurement. I put the full 11g of nottingham yeast into the wort (half in each demijohn) and of course this morning I have one runaway ferment and had to install a blow off system into a jug of water. The other one is slightly (only slightly) less energetic but hasn't (yet) started to blow foam through the airlock. If it does, I'm in a bit of diffs as I only have one blow off hose, without taking apart my bottling hose.

 

[Musky01]

I've been searching the forums and feel like this answered my question but would like some input from someone that has done it.

I have been making 5 gal batches for the last 3 years but want to make a few test 2.5 gal using my same setup.

In a 5 gallon batch I am always at 1.25 gal/hr so in a smaller batch I should expect the same rate? Boil off is not a function of volume but of surface area? Am I getting this right?

 

[flushdrew42]

i make 1.5gallon batches. i have a two gallon pot, when i boil, i'm boiling 1.75 gallons and ending with a little more than 1 gallon. and i top up to 1.5. in a 60 minute boil.

my first BIAB AG batch i had 3 quarts of strikewater, 1 gallon of sparge. (1.75g boil)

and needed a little more than 1/2 a gallon to hit my 1.5G line on my brew bucket.

 

[helibrewer]

The gallons/hr boil off is a function of the kettle geometry (surface area of liquid) not the volume being boiled. Also a pretty easy rule-of-thumb for sparge water is to use the same volume as your desired batch size...works very well.