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.
Brew Day Notes
1045 – Start dough-in
1100 – Dough-in finished, start mash rest
1120 – Quick stir, then start mashing
1237 – Mashing done, leaving it to settle so that I can get some readings.
1240 – Looks like 38 litres exactly with malt pipe in place. BF predicts 27.14 litres mash volume, hope my numbers will be good after sparge also.
1248 – sample taken, start sparging. Volume looks like 20 litres but that’s very approximate since there’s liquid still draining out of the malt pipe but I don’t want to let the top get too dry. Sparge hat working beautifully.
1255 – pre-sparge gravity is 1.061 (1.048 @ 55.4℃)
1300 – sparging finished, just letting her drain for a bit.
1305 – boil volume is 29.75 litres (target = 28.86) with pre-boil gravity at 1.050 (1.035 @ 58.8℃, target 1.048). Numbers looking good so far!
1353 – boil tracker on, 60 minute additions in. I’m including a nub of Lipohop to guard against pool-over as there’s a good amount of hot break which refuses to stir in, hopefully not an omen.
1425 – 30 minute additions in, no problem so far. Boil being maintained at between 67 and 70% heater power, pumps at 20%.
1442 – 15 minute additions in. Levels look like 28.2 litres (BF predicted 26.46) dropped the trubinator and chiller coil. Levels now 27.5 approximately.
1451 – identified a leak in the Fermzilla, which is being tested with sanitiser ahead of deployment. Investigating.
1511 – replaced o-ring between cone and butterfly valve with a likely looking item from stock, refilled with sanitiser and gas to 20 PSI for testing. 20 minute hop-stand additions in, chilled to 80℃ and heater set to automatic. Replacement part ordered.
1531 – hop-stand ended, starting to chill down to 20℃.
1550 – starting transfer to fermenter now that pressure seems to be holding with new o-ring.
1605 – transfer finished. Fermenter volume 23.75 litres on Fermzilla’s scale, OG 1.056 (1.055 @ 22.8℃, predicted )
1618 – pitching the yeast starter, and, because I’m not convinced, my remaining packet of CML as well. Red tilt deployed, spunding valve set for 5 PSI and off into the fridge at 20℃.
1745 – cleanup finished.
