Calculating SRM of Parti-Gyle - Page 2 - Home Brew Forums

 Home Brew Forums > Calculating SRM of Parti-Gyle

09-09-2011, 01:33 AM   #11
michaeltrego
Recipes

Sep 2009
Amherst, NH
Posts: 396
Liked 22 Times on 19 Posts

Quote:
 Originally Posted by DrJerryrigger will do! I'm mashing right now. I'm sure things will work out differently than predicted, but I'll go back and calculate with the volumes and SG that I end up with, to see how things work out.

09-09-2011, 02:39 AM   #12
DrJerryrigger
Registered User
Recipes

Oct 2010
mass
Posts: 3,218
Liked 9 Times on 9 Posts

Quote:
 Originally Posted by michaeltrego I'm curious about your parti-gyle session - how did it go?
poorly, in fact it's still going. It's been three days!

09-09-2011, 02:56 AM   #13
michaeltrego
Recipes

Sep 2009
Amherst, NH
Posts: 396
Liked 22 Times on 19 Posts

Three days....I thought you were brewing yesterday?

09-09-2011, 05:24 AM   #14
DrJerryrigger
Registered User
Recipes

Oct 2010
mass
Posts: 3,218
Liked 9 Times on 9 Posts

Quote:
 Originally Posted by michaeltrego Three days....I thought you were brewing yesterday?
I started early. Anyway I'm boiling now. It will take some time to figure out my notes. I really botched the calculations on this SRM thing because of a sparging technique I tried. I mashed 7lb of base, and use the sparge from that as the mash and sparge water for the second mash. I should have used the other grain in that, but I'll see if I can figure out what ended up happening, and calculate from that. It's been a long few days. I need a shower and a clean shirt.

09-09-2011, 12:19 PM   #15
ajdelange
Recipes

Aug 2010
McLean/Ogden, Virginia/Quebec
Posts: 9,431
Liked 1565 Times on 1191 Posts

SRM = 12.7*A430 = 12.7*e*c*1 where A430 is the absorption in a 1 cm cell at 430 nm, e is the extinction coefficient and c is the molar concentration. Making lots of somewhat shaky assumptions one can reason, therefore, that a 20 °P wort from a parti gyle mash would have twice the SRM of a 10 °P wort from the same mash (because °P, while they are not a molar concentration unit reasonably closely approximate one). Thus, if you believe in the commonly used MCU scheme for calculating color and you treat both gyles the same with respect to length of boil then you might be able to come up with rough estimates of the color by linear apportionment.