We are a start-up distillery in Richmond, VA, and have been struggling with our blending/proofing down operations.
I Have read a lot of good advice on the ADI forums on this subject and have settled into the following sequence for proofing down our Bourbon (110pf - 90pf) and Vodka (191pf - 80pf) for bottling using 55 gallon stainless steel drums. We are using AlcoDens to calculate our batch blending and hydrometer correction readings. We are proofing down in two stages as follows:
Take hydrometer reading of the source tank (270 Gallon Totes)
Calculate approximately how much (by weight) of the source spirit to achieve 52 gallons at 1-2 degrees proof above target bottling-proof
Weigh out the calculated amount and get an exact weight of the source spirit
Take proof measurement of source batch & update calculation in AlcoDens using this proof and weight to determine the weight of distilled water to add to reach target proof.
Weigh out the calculated amount of water in the bottling drum. Agitate with a pneumatic mixer and add source spirit until the calculated batch weight is reached
Mix for 3-4 hours then let sit for up to 12 hours
Take proof measurement of batch and update calculation in AlcoDens to determine how much additional water to add to reach bottling proof.
Mix for 3-4 hours then let sit for up to 12 hours
Recheck proof and repeat if needed to get bottling proof.
Wait 12 hours after last check to start bottling
Now typically,am if I start bottling right after the last 12 hour wait the proof is stable at the checked proof during my bottling checks but not always. Tank is sealed and stored in the same conditioned space when not bottling but am struggling to figure out why the proof can change by as much as 2-3 degrees proof (which would not be good for bottling) by just sitting but cannot find any information on how much time it may take for the proof to settle of even if that is what is happening
Any insight from the community is welcome - although I am not trying to stir up the slow vs fast proofing debate as I realize I am proofing down using the fast method.
Thanks in advance
Bob Donovan