Quite a good brew day today. Only one small error (heaters on Auto rather than Auto Mash, no scorching though) and I’m very very close to all my numbers, both in terms of volumes and gravity. The only exception there is the amount of trub loss when using the Trubinator, and going forward I may think about creating a dedicated equipment profile for when I’m using this piece of kit. Unfortunately doing so would effectively fork any subsequent tweaks as I’ll be tuning two profiles, so we’ll have to think about this some more.
One thing which did give me slight concern today was my desperate under-pitching of Voss Kveik. If memory serves correctly I used half a sachet of slurry on a previous incarnation of Geronimo and then a quarter on Jackknife Barber, leaving me with one quarter sachet and the hope that my previous doses hadn’t been too greedy.
I warmed the alarmingly light bag during boil using my laptop, weighed it at 51.93g, and pitched it at around 24℃ with the empty bag weighing 10.71g – so 41.22g of yeast for 21 litres of 1.064. Nothing happened in the following hours and nothing continued to happen when I turned in for the night, but at around 05:00 the next day it took off in typical Kveik fashion. The following morning I was relieved to see I’d remembered to fit the spunding valve, but disappointed to find I’d adjusted it too high, because it was hissing merrily at around 17 PSI. Voss is one hard, mad bastard. Reduced pressure gradually to 5 PSI as I don’t want to suppress too many Esthers or release too much hoppy goodness via CO2 when it’s time to dry-hop. All good for now.
Kicked off a Maris and Citra SMASH with Gregg this morning, no incidents and very much bang-on the numbers. We’re under-pitching Voss on this one, using just ¼ pack instead of the ½ that went into my last brew, Geronimo III, with the idea being that if it won’t kick off in the same timeframe we can always throw in the rest of the bag. Nothing else to report for now …
A good brew day without incident, the only unexpected factor being that I was supposed to be doing a SMaSH with a friend today but that was cancelled, so Geronimo it was. Not having time to make a starter and with a whole bag of OYL-061 Voss in the fridge I decided to try under-pitching and a warm ferment in order to get some of the supposedly fantastic citrus flavours creeping out.
We’ll see how that goes, but for now I’m pleased to report that despite a slow start I’m seeing strong fermentation since the small hours of this morning (approx 14 hours after pitching) and I see that the spunding valve was set way too high at 15 PSI. I’m dialling that back to 7 PSI because I want the esters to have a chance, at least until I dry-hop at which point I’ll increase back to 15 PSI to give me a safety net for cold-crashing.
I believe I was right to attribute yesterday’s initial bubbling of the blow-tube to temperature expansion since there was no sign of foam, but this morning’s a different story, with a nice cake of healthy krausen sitting on the FV’s surface just 18 hours after pitching.
The blow-off tube is popping constantly and the spunding valve has settled on exactly 5 PSI and is hissing quietly. I’m wondering if 5 PSI is enough to suppress some of the yeast’s desired character so maybe we’ll try one without pressure at some point, but for now I like the head start on carbonisation and prevention of O2 ingress during cold-crashing.
It’s 21:15, about eight or nine hours since pitching, and this Kveik has just taken off in the last hour or so. I’m seeing a growing carpet of foam on top of the wort and have fitted a blow-off bottle, moving the spunding valve away from the likely erupting Krausen.
I’ve set the spunding valve to 10 PSI by dialling it high and filling the blow-off bottle from my CO2 tank, then reconnecting the valve and opening it until the pressure dropped back down to 10. Unfortunately I didn’t de-pressurise the bottle further, and when I reconnected it to the FV a small amount of sanitiser rushed up the dip tube as the vessels equalised. Hopefully that won’t trouble the wort or the yeast too much in this important early stage – oops!!
The foam that’s been atop my brew since Primary started has now cleared up, and the fermentation curve is beginning to flatten out. I expect tomorrow the curve will be completely flat so I’ll take that as my dry-hopping point, aiming to cold-crash 3 days later.
It’s 18:00 and there’s a good amount of Krausen atop this brew now, so I thought I’d capture some for future use before it gets too far into development. Cleaned a big jar and a ladle, gradually de-pressurised the Fermzilla, and filled that jar with glorious foam. Once that was done I fitted the jar’s lid and swung it about in order to compress the foam through G-force, allowing me to get another couple of spoonfuls in there. On refitting the Fermzilla’s lid I saw the pressure climbing up again, hitting 10 PSI 15 – 20 minutes later. The jar’s in the fridge and the contents will be decanted onto parchment and dried then frozen at some stage.
According to the Tilt, things started happening around 04:00, and when I checked in this morning there was a good covering of foam on my brew. I didn’t bother calibrating the spunding valve yesterday because I’m short of gas (in fact I’d almost forgotten to refit the valve after swapping out the first Tilt) so I just guessed the number of turns needed for my target of 10 PSI, and that transpired to be closer to 20 PSI. Sorry Fermzilla, sorry Tilt! I backed the valve off gradually over the next couple of hours and she’s now sitting pretty at 10, will leave it to build a bit longer before harvesting some yeast.