Pre-Boil Volume - First AG

[Col_klink]

Hello All,
I got a nice 10 gallon kettle for Christmas and should be brewing my first all-grain batch within the next couple of weeks

Anyway, I have been doing a lot of reading to prepare and I think I got most of this. However, one thing that has me scratching my head a bit is boil volume.

Specifically, what actually determines what your pre-boil volume should be?
Is this just a function of boil off rate? Contrary to what I've been reading, it seems (in my head) this is NOT the case since the size of your grain bill determines mash/sparge volume which actually determines you pre-boil volume.

Which brings me to my next question, I make 5 gallon batches. Assuming I have to boil for say 1.5 hours to boil off to 5 gallons, do I wait until I am 1/2 hour into the boil to add my 60 min hops?

Thanks in advance for the help!

-Klink

 

[runkelia]

I find that if I collect 7 gallons, I have about 5.25 after boiling for an hour and cooling.
Typically bittering hops are only boiled for 60 minutes.
I don't see the advantage of boiling for 90 minutes, unless you over collected and want to make a high gravity wort.

 

[freisste]

A bigger grain bill may require some more sparging which will get you a larger preboil volume. You are correct.

However, there are other losses besides boiloff. These include dead space in your system (worse if you have more hoses and pumps to move things around) and trub loss. Basically, figure out how many bottles you want to fill, add a little for what is stuck in the bottom of your bottling bucket, add some or trub loss and you are at the volume in your FERMENTER. Add to that your losses in hoses and such as well as losses to the pile of crap leftover after you whirlpool, if you do. Add to that your boiloff volume and you have what you should have in your kettle when you turn the flame on.

 

[freisste]

Regarding your second question, you are correct. If you need to concentrate your wort by boiling for 90 minutes (or you use a lot of pilsner which requires a longer boil to drive off DMS precursors), boil for 30 and then add 60 minute additions.

Or add 60 minute additions at the beginning. You will get slightly more bitterness out of them. If you are already doing a 90 minute boil it is worth it if you like the bitterness. If you were going to do a 60 minute boil, the bitterness you would get out of the extra 30 minutes wouldn't be worth it.

 

[planetscott]

I find that if I collect 7 gallons, I have about 5.25 after boiling for an hour and cooling.
Typically bittering hops are only boiled for 60 minutes.
I don't see the advantage of boiling for 90 minutes, unless you over collected and want to make a high gravity wort.

I see someone had the same response as me.....No sense in beating a dead horse or sounding like a know it all ass....

 

[Col_klink]

Thanks guys that helps! One other question for ya:

How much sparge water do you use? I have seen some people say estimate about .5gal/lb and others say .25gal/lb. Any thoughts?

 

[Yooper]

Thanks guys that helps! One other question for ya:

How much sparge water do you use? I have seen some people say estimate about .5gal/lb and others say .25gal/lb. Any thoughts?

Sparge up to your boil volume. It's not a set amount.

 

[planetscott]

Thanks guys that helps! One other question for ya:

How much sparge water do you use? I have seen some people say estimate about .5gal/lb and others say .25gal/lb. Any thoughts?

Enough to reach my pre-boil volume. It's a learn as you go process to where you get a feel for how much you need. Sometimes I miss. Either way, I do end up with beer.

 

[Col_klink]

Haha, I guess ending up with beer is the goal right? Thanks for the input everyone, I'm sure I will have more questions after the first batch

-Klink