The temperature has been increasing steadily with fermentation and sunny weather. I was hoping to keep it around 19℃ which is the optimum for the WLP001 yeast I’m using (range: 19 – 21℃) and really need to get myself a fermentation fridge so that I can control this better. This beer doesn’t really need esters and it certainly doesn’t need fusel alcohols, so I’ve no hesitation in applying some pressure to the fermentation after 24 since kick-off.
Speaking of fermentation, it’s not been a quick starter, with the first signs of life in the airlock showing maybe 4 or 5 hours after pitching both tubes of liquid yeast. I was beginning to get worried; one of the ice packs that accompanied the yeast on its voyage over to us had become punctured by something else in the box, and I had doubts whether or not the yeast had really been kept at 4℃ all the way as intended. Things did start happening that evening, and by morning there was a thin layer of foam on top, maybe ¼ inch thick, with the usual frenzied activity going on underneath.
By noon that had increased to almost an inch, and when we came back from an afternoon walk we swapped out the airlock for a spunding valve set at 10 PSI. This had a dramatic effect on the foam, which transformed into a thick Krausen over the next few hours, almost touching the vessel’s lid by evening. To save the spunding valve I decided to move it to a spare keg and then connect that to the Fermzilla with a blow-off tube, but forgot to pre-pressurise the keg and caused much of the Krausen to head straight down the tube as soon as it was connected. I removed and cleaned the tube just in case, must remember to do the same for the Fermzilla’s PRV once this is done.