I’ve been enjoying this brew for just over a week since I kegged it, and the delicious, pungent aroma and flavour of fresh hops has been fading steadily from day one. Now it’s just barely detectable, and I think we’re about halfway through the keg. Must get better at logging drinks to be honest. Maybe try bottling some of my next batch to see if that’s a better way of preserving the flavour?
Having gone in quite heavy on the hops for this recipe I want to make sure the flavour lasts as long as possible, and that means minimising cold-side oxidation. In addition to purging the keg before filling I’m going to have a go at adding Sodium Metabisulfite (SMB) to the keg since some people think it’s good at scrubbing oxygen. Surely worth a go? If I’m happy with the hop retention as I drain the keg over the coming weeks I may well carry out my own A/B test on a future brew. Today however I simply added 0.3g of SMB (crushed Campden tablet) to the purged keg before refitting the lid and purging it again, like the first time by slowly blowing 70/30 into the out-post with the PRV pulled for a couple of minutes.
Anyway, the beer was transferred from my Fermzilla to a 19 litre Cornelius keg using the floating dip tube coupled with my finest inline filter, because it’s a double dry hopped brew and there may still be some crud transferred as we get near the end, despite the cold crashing. The filter’s barbed connections coped happily with 12 PSI of pressure on transfer, but I did have to screw the bowl on extra tight as there was some evidence of sanitiser leakage during purging / pressure testing ahead of deployment. I think this is due to the mesh cartridge being slightly too tall for the housing, or the gasket being slightly too thin – either way she wants a good hard twist to make sure everything’s sealed.
Once the 19 litre keg was filled I wanted to put what looked like almost 4 litres of surplus into a mini keg via the post on the collection jar, but although I was fairly careful the trub became disturbed using this method, and went from being settled below the take-off post to getting fairly well mixed with the rest of the brew, which by now had also picked up much of the settled hops from the sloped sides of the vessel. I was going to transfer the murky solution anyway, thinking that I can always crash it out in the keg, but for some reason the flow stopped and I got barely 2 litres. Guessing that this was due to the filter finally being clogged I just binned the rest when I really should have switched to a straight transfer tube, but during clean-up the filter actually looked pretty clear, making me wonder again if it’s worth bothering with if kegging crashed beer. Let’s make a note:
#wisdom: stop using inline filter by default if kegging cold-crashed brew, at least until a concrete reason for doing so arises.
#wisdom: if transferring FV dregs to a mini keg rather than dumping them, use a straight tube (without filter) and don’t worry about trub, which can be cold-crashed out later.
While filling the first 19 litre keg I let it run a tad too long using condensation on the side as my fill guide, and ended up with some liquid coming back out of the gas post near the end. In order to recreate some head space and also give me a sample to measure, I fitted a small tap to the liquid post and filled my trial jar, setting it aside while cleaning up in order for the foam to settle. Even so it was difficult to get a decent reading, because dropping in the hydrometer caused more bubbles to rise in the carbonated brew. Maybe I should have chilled and wetted the hydrometer first? Anyway, I measured a FG of 1.008 (very approximately) at 16.9 ℃ which makes for 1.007, and 5.6% ABV. Happy with that, and extremely happy with the hoppy taste from the trial jar. Let’s hope the SMB does it’s job and we get to enjoy this one for weeks to come!
The fermentation curve is creeping the wrong way – lets get this chilled and packaged ASAP
Added the second dose of finishing hops just now, 35g Citra again via the top after de-pressurising the vessel. This time there was a substantial buildup of foam as I neared zero pressure and took the lid off, and I think if I hadn’t have thrown in the hops and screwed the top back on quickly there would have been a mess to clear up.
As it stands I may have rushed the refitting of the lid because the vessel wouldn’t hold pressure when the top was back on, so I had to remove it a second time. No issues after re-seating it, keeping pressure fine and back up to 12 PSI. I’m not sure if I should count the cold-crashing as part of the dry-hop duration (though interesting experiments have been done) so I might cold crash a day early and only for 24 hours in order to retain as much of the good hops as possible.
The fermentation curve has levelled out over the past 36 hours so I decided to add the first dose of finishing hops now rather than wait another 2 days as per recipe, which was adjusted (on batch) by reducing the primary fermentation step by 2 days and adding a 3 day cold-crash. The entire collection jar appears to be full of yeast now as opposed to just a quarter inch from just a few days ago, so I’m taking this as another sign that fermentation is done.
Over the past couple of days I’ve been thinking about how to get the most utilisation from my hops (and not have them sitting dormant in the jar) and in the end I decided to close the butterfly valve on all that dead yeast before slowly de-pressurising the Fermzilla and chucking the hops in via the top after giving them a cursory flush with 70/30. The idea here is that once the hops drop down they’ll sit on top of the closed valve instead of in the jar or on the dead yeast, which gives them longer exposure to the beer and minimises any biotransformation to whatever yeast is present above the valve. I can always give it a shake as well without disturbing the yeast in the collection jar, which will hopefully increase utilisation.
High Krausen has been and is starting to recede now, but there’s still a covering of good, thick foam across the top of this brew.
What’s really interesting is the nice, bright hue that this beer is taking on – it’s changed remarkably since fermentation started about 12 hours after pitching, and seems to be getting a shade lighter with each passing day.
Inside there’s the usual turmoil of suspended funk, though we’ve not got as much settlement in the collection jar as I’d expect – no bad thing. This bodes well for when I need to double dry-hop in five days time, and I’m thinking of leaving the pressure up at 12 PSI and just removing the collection jar with the butterfly valve closed. My thoughts here are that I won’t subject the Tilt Pro to successive pressure changes (not that it’s ever complained before, but still) and I’ll minimise oxygen ingress since I can flush and re-pressurise the collection jar once I’ve added the hops. Need to think about using this approach some more in the coming days.
Another good brew day! Looking at the counter this is my sixteenth all-grain brew, and I’m getting better at remembering to take my measurements and making useful notes. The Fermzilla is in the fermentation fridge and I’m looking over the raw notes (below) so let’s see what we can learn.
Looking at Losses
First of all, there hasn’t been that much volume lost during mashing, with before and after being close to 26 litres malt + water. Sparge water was 9.7 litres (11.41 HLT) and mash water was 22 litres, though I was a bit generous on the sparging, having filled the HLT to a smidge over 12 litres – so 600 ml over. The mash tun was spot-on 22 litres, chiller dry at this point and malt pipe in place.
Sparging until the HLT started sucking air brought the volume to 27.5 litres, but Brewfather predicted 28.86 litres, so a good 1.35 litres down. The proper way to account for this within Brewfather would be to crack on and record a fermenter top-up later, but I didn’t have any mineral water to hand so I added around 1.5 litres straight from tap to the kettle, on the basis that the subsequent 60 minute boil would take care of sterilisation. With the extra water in the kettle I was looking at a pre-boil volume of 29 litres at 1.047 against 28.86 and 1.044, so I’m still ahead on both counts.
I’m going to record the 1.5 litre pre-boil addition as fermenter top-up, because there’s no sparge loss measurement in Brewfather. This will probably give some crazy mash / brewhouse efficiency numbers, but that’s OK. Going forward I’ll modify the hardware profile to include an extra 1.5 litres in my HLT dead space since that feels like the best way of handing this situation until I think of something better.
0815 Starting dough-in
0830 Start mash rest
0850 First stir, start mashing
0910 Forgot to measure levels at the start, 15 minutes into mashing and it looks like we have 26 litres in there. BF predicted 25.35 so we’re still on target.
0915 The pump’s been making an odd clicking / knocking noise that disappears when restarted but comes back in a few seconds later. At first I thought it might be something stuck in the impeller but now I’m wondering if the bearings are OK. Might be worth investigating spare parts before I get a failure.
0934 Last stir, want the mash to settle for the final 20 minutes in order to trap as much floating crud as possible
0950 Mash almost done, shutting off centre pipe flow in order to let her equalise before I can measure losses so far. It’s taking quite a while for the malt pipe to drain which hopefully indicates a long sparge ahead. HLT now up to 75℃.
0955 Looks like we still have 26 litres in there, so minimal losses during mash this time. SG 1.063 (1.047 @ 60℃)
1000 Starting vorlauf
1005 Starting sparge
1015 Sparge water out – that didn’t take long! Looks like we have around 27.5 litres in there now, BF predicted 28.86. How’s that possible, when my mash losses were so minimal? SG 1.050 (1.035 @ 58℃) against predicted 1.044, so I’m adding tap water to 29 litres, sod the figures. SG now up to 1.047 (1.032 @ 58℃).
1105 Rolling boil started, waiting for the impressive hot break to dissipate before reducing heat temporarily and throwing the 60 minute additions in.
1110 Tracker started, additions in.
1200 15 minute additions in, measuring levels ahead of cutting in chiller and trubinator for sanitisation: 27.75 litres.
1205 Extra hardware is now in, levels look like 26.75. Ramping back up to boil with tracker paused.
1225 Boil’s done, switching on chiller for 20 minute hop-stand.
1245 Hop-stand done, starting to chill down to 20℃. We have 25.5 litres approximately, SG 1.050 (1.030 @ 67℃) against predicted 1.048. Not topping up further.
1400 Clean-up finished. Red tilt was deployed about 40 minutes ago, volume with starter approximately 23 litres – hurrah!