Not much to add today other than the brew notes. This one went pretty darn close to the numbers in terms of gravity and also volumes, so I’m happy to have breached the 80% marks for mash and brewhouse efficiency.

Pressure Leak

There was only one hiccup: when I filled the Fermzilla with sanitiser while boiling wort, I thought I may as well apply some pressure in order to see if everything’s screwed together properly. Pressure did start dropping, indicating a loss of almost 1 PSI every couple of minutes according to the spunding valve. To determine if the leak was from the top (not serious) or from the bottom (potentially messy) I added some more sanitiser so that the collection jar and cone were fully covered, then reapplied pressure with the FV standing over a plastic bowl.

At 20 PSI I got half an egg-cup in around 10 minutes, and it turned out to be due to a partially deformed o-ring between the cone and the Butterly valve, with some irregularity in the roundness of that part also. That bit worried me as I swapped out the o-ring for my only spare but subsequent pressure testing validated the fix. Thinking back on it, I do recall that there was a suspicious dribble of sanitiser on previous tests under pressure, and I thought it could be from the butterfly valve itself, which I’d disassembled and checked without change. Could be that the o-ring was on its way out for some time, and the last cleaning strip-down sealed its fate. Either way, a replacement part is on the way.

Starter Supplement

The only other thing worth noting is my dissatisfaction with starter number 2, which I supplemented by pitching my other sachet of CML Ale yeast on top of the starter. Hope that works out all right.