The process is called parti-gyle and it was used to make abbey ale, dubbels,
and trippels. The rough rule of thumb is that the first 1/3 of the sparge
has 50% of the sugars. If you sparge 6 gallons and keep the first 2 gallons
separate, it should be twice as strong as the other 4 gallons. Randy
Mosher's book has charts for it and everything else chartable as well.

-Bubbles-

"Matt Schmidt" <mschmidt@stradley.com> wrote in message
news:3a59bf88.0307070819.558903d7@posting.google.com...[color=blue]
> Is there a way to determine gravity of the sparge?
> My plan, & I will do this twice to collect the desired volumes.
> mash 12# grain with 3 gallon H20.
> Collect the first runnings in one bucket and then collect the sparge
> in a seperate bucket.
> I should then have approx 5 gallons of high grav and about 6 gallons
> low gravity liquor.
>
> how do I predict gravity / volume before and after boils?
> If I'm shooting for OG 1.05, and my 6 gallons are say 1.045, how much
> should I expect to collect in order to get 1.05.
> Are there formula for this?
>
> TIA
>
> ~Matt[/color]