Crash test

[bunny]

Thursday I started a test batch of sugar wash to try to determine how much CaCO3 is required to prevent a pH crash using distilled water.
The recipe I used is:

16lb beet sugar
Distilled water to total 12gallons
1 T DAP
75-85g CaCO3
1/8t epsom salt
1 B Complex and 1 B 12 crushed vitamins
1Cup bakers yeast
Pitch temp 92*f

After 24 hours:
pH 4.1
SG 1.012
temp 93*f

After 48 hours:
pH 4.1
SG 0.0992
temp 95*f

This is my "go to" recipe for neutral except using hot and cold tap water. (The distilled water was just for this one test)
My average ending pH runs a little higher roughly 4.5-4.7 indicating a little pH help from the tap water.

I don't know if this will translate to a larger batch or a batch with less yeast pitched.
What it looks like to me is 75-85g CaCO3 powder(NOT GRIT OR WHOLE SHELLS) or 3 rounded Tbs, or 1/3 level cup will get the job done and prevent pH crashes in washes containing 16lbs of sugar.

YMMV

[NZChris]

With an almost identical recipe except for the CaCO3 and distilled water, I got a starting pH of 6, which dropped to pH 5 the next day. Added 80g of whole clam shells. It finished at pH 6 having dissolved 33g of shell.
OG 1.067. FG 0.997