I'm trying to formulate a partigyle batch for this weekend. I'm planning on making a double IPA and a Pale. I've never done a partigyle, so I consulted the web to try to find out how to do the calcs, but have come up with some conflicting info (I think).
I plan to batch sparge 50/50. I want the double to come in around 1.070.
According to (2) and (4) below, I want to start with a recipe that would give me 1.060.
According to (3) below, I want to start with 1.0530. (1) basically agrees with (3).
So, which one is it? Thanks!
"Roughly speaking, the second batch will have half the gravity of the first batch. "
Batches split into two equal volumes have a different ratio: ~58% of the extract will be in the first half of the runoff and ~42% in the second half. For example, a 15-gal master batch designed to produce 16 °P wort contains 240 °gals (15 X 16 = 240). The first half will be 18.56 °P (240 X 0.58/7.5 =18.56); the second half will be 13.44 °P (240 X 0.42/7.5 = 13.44).
1.060 total -- 1.080 (first half), 1.040 (second half)
For a 50-50 split by volume, with half of the wort in each batch we get a roughly 58% of the gravity points in the first batch. So a 1.060 overall batch OG would translate to a 1.070 first runnings and 1.050 second runnings, with both of equal size.