Denny and others please chime in...
So I've done about 10 all grain batch sparge brews now and all went well until my last debacle where I mashed way too thin that I extracted tannins and screwed up the entire batch. Made me do more research and rethink my process. I think my process had no issues before because I've never made any beer with OG less that 1.060.
My process up to now has been this:
-Calculate my strike water volume (taking into account MT dead space and grain absorption) so my 1st runnings are about 1/2 of my preboil volume. Vorlauf.
-Measure my 1st runnings, subtract from pre boil volume, and sparge with a volume that should be about 1/2 of pre boil volume. (temp about 190, after it is in MT it is about 167). Vorlauf, collect.
-Start the boil, laugh, have a beer and make some beer.
I do take a ph of the mash and it has always been between 5.1 and 5.3. I never really worried about quarts/lb ratio.
Now I realize that with weaker beers, the ratio matters. I haven't really gotten into water chemistry yet, but I read that you don't want to go over 2q/lb for ph reasons in the mash. Is there a similar rule for amount of sparge water? I think I read somewhere Yooper said don't go over 3q/lb in the sparge.
For instance, I am brewing tomorrow and the total grain wt is 8.75lb. My pre boil volume is 8gal. My old way would say I loose 1.34gal to absorption and MT dead space so my strike would be 5.34gal. 1st runnings would be 4gal. I would sparge with 4 gal, and get my 8 gallons pre boil. But that is about 2.45q/lb, and now I worry about ph problems, tannin extraction....
So should I:
Strike with 4.25gal (about 1.8q/lb), get about 2.9gal 1st runnings, then sparge with about 5 gal? Or is 5 gal sparge for 8.75lb too thin?
Strike with 4.25gal (about 1.8q/lb), add about 1gal of 190deg water to MT (top off/mashout?), then get about 4gal 1st runnings, and sparge with 4 gal to get total pre boil volume?
Damn, this tannin thing has me upset.