Tag Archives: fermentation

Dec 202209Fri

Throwing in those hops has restarted fermentation and I’ve dialled the spunding valve up to 15 PSI, where it’s hissing gently. This is great; we’re displacing introduced oxygen with CO2 and storing some pressure to prevent suck-in during subsequent cold crashing.

Also good is an apparent correction to the gravity readings. Presumably there was some Krausen buildup on the Tilt which caused it to report a higher value, but de-pressurising the vessel ahead of dry-hopping must have given it a knock and we’re now reading a gravity value that’s much closer to the expected FG. It’s not uncommon to get a bit of a jump from the Tilt when depressurising, so I deleted the most recent two readings as soon as the lid was back on, but the following readings were also at the new value so I’m confident that it’s reporting correctly, at least for ‘light’ beers such as Geronimo.

Dec 202208Thu

0800, Thu 8 Dec

The airlock has been hissing loudly since fermentation started about 14 – 18 hours after pitching, and although the graph hasn’t flattened out completely I see that the surface of the brew is completely clear, and all yeast has disappeared apart from the usual remnants of dried Krausen around the rim.

So what to do now? I’d like the finishing hops to go in there before fermentation is 100% done so that we get a little bit of CO2 driving out any of the inevitably introduced oxygen, and with that curve not levelled out yet (at 66% attenuation, ostensibly) I think we have another day or two, but where’s the yeast? Was I right to under-pitch. Maybe I’ll wait until this afternoon before making a decision.

16:00, Thu 8 Dec

I checked the fermentation curve again this afternoon and it does indeed appear to have flat-lined, so I threw in the finishing hops and deployed the sanitised floating dip-tube. No purging or undue ceremony, hopefully there’s still a bit of activity in there to drive out the oxygen that I’ve undoubtedly introduced.

Nov 202230Wed

I don’t think there’s anything going on here, possibly due to the reduced yeast starter following the boil-over. Let’s increase temperature by a few degrees to give the yeast a chance to finish off before cold-crashing.

Pretty much done after 4 days
Oct 202226Wed

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.

Geronimo II performing into the blow-off tube

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.

We’ll see where it goes. Looking good for now.

Sep 202216Fri

Just a quick note to say that this brew has been sitting there idle for a good 26 hours since I pitched Omega DIPA “Conan” OYL-052, and I was getting worried.

But Allah Be Praised, she’s finally off! Not much to look at yet, just a blanket of fine foam atop the brew, not even touching the sides. But we have action, and that’s good. I don’t remember any other yeast taking quite this long … probably 12 – 18 hours, but not 26. Still, we’re off and that’s all that matters. The spunding valve had already hit 8 PSI by the time I caught it, so I dialled it down to 5. It’s not very precise or responsive at the lower pressures.

Go do your stuff, yeast.

It’s alive … aaaallliiiiive!
Sep 202204Sun

Checked in on my imperial stout just now, and maybe I should have fitted a blow-off tube right from the start, because it seems we’ve had something of an explosion. I’m not sure what caused the airlock to separate into two halves and explode toward the top of my fermentation fridge, but I was half expecting to find a dent in the ceiling.

Replacing the stricken part with a taller type of airlock caused that one to fill up immediately as well, so I did what I should have done yesterday and fit a blow-off tube filled with sanitiser. Let’s hope this one doesn’t erupt.

Yeti performing into the blow-off tube / bottle

#wisdom: Air-locks are for beginners, just use a blow-off tube from the start.

* the original brew day was delayed 24 hours by a ‘gastric episode’ which may or may not have been related to rare duck.

Mar 202217Thu

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.

Feb 202215Tue
4 days into Primary

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.

Feb 202201Tue

Things have been going pretty well since I started this brew 11 days ago, and I’ve not posted as many notes or pictures as with previous brews, partly because I’m more confident now that I’ve got 15 under my belt, partly because it’s all gone to plan.

Slow Start

That said, it did take almost 24 hours for the yeast starter to begin doing its thing, which makes me wonder if I’m doing something wrong there, or if making a starter is superfluous. Pretty much all dry yeast manufacturers recommend dry-pitching straight from the packet, and pretty much all seasoned brewers advocate the creation of a starter instead. Brewfather sides with the latter, recommending several packets of yeast if dry-pitching into a 23 litre FV, yet the vendor reckons one packet is enough. I can’t really comment since I’m still quite green, and running a parallel test is out as I still only have one fermentation fridge. I might try dry pitching next time around, but that’s likely to introduce a certain amount of variance thanks to age of ingredients among other factors.

A dose of … Meatballs?

I don’t know if it’s the use of Polyclar together with Protafloc or something else, but the protein / snot that was transferred from the kettle has clumped together to form mobile lumps which look a little like meatballs. These were quite lively throughout fermentation and have now settled down. Most strange.

Started Cold-Crashing

According to the Brewfather app I was due to drop the temperature down yesterday, but the SG curve appeared to be declining still so I left it another 12 hours. Visually there’s nothing going on in the FV now and the curve seems to be levelling out, so I’m setting the Inkbird for 1℃ and will leave it there for at least 4 days before I transfer this to a keg for lagering. About a week before we’re due to take this to a friend’s party I’ll transfer to smaller party-size kegs, ideally leaving the settled trub behind and giving us a better shot at getting it into a fridge.

2022-01 Sarka, 11 days into Primary
Nov 202123Tue

Of my three active ciders this one’s doing the best. I’m seeing the same 1.002 (1.003 / 15.5℃) that I had 2 weeks ago, clearly a case of the yeast starter having gotten to work straight away and now finished. The taste is the cleanest of the three as well, which makes me think this will be fine as a slightly sparkling brew or just flat, with perhaps only minimal sweetening. Will cold-crash in order to remove some of the haze, don’t think I’ll worry about Campden.

Nov 202123Tue

We’re at 1.004 with Best Wellies (1.005 / 15.6℃) and I’m going to leave this one another week to make sure she’s done, because we were 6 points higher at last check-in 2 weeks ago. There’s a slightly tart sourness to this cider which makes me want to sweeten it substantially and carbonate it for a sunny, summery drink. Maybe cross-flavour with some fruit? A little natural cloudiness as well so this too will be cold-crashed.

Nov 202123Tue

We’ve dropped 2 points since my last measurement 14 days ago but right now there’s nothing going on, no airlock activity at all so I’m tempted to call it done at 1.005 (1.006 / 16.1℃) for 5.0% ABV.

In terms of taste it’s actually pretty good, with the Opshaug Kveik imparting an interesting flavour which makes me want to maybe sweeten this one just a touch but leave it flat like a traditional Scrumpy.

Next steps would be to rack it to a clean vessel along with some Campden and then cold-crash in order to take out some of that weird cloudiness that’s hanging around from the starter.

Nov 202121Sun
2021-11 Yeti at one week into Primary.

Fermentation has drastically slowed on Yeti. Brewfather’s graph shows a distinct flattening of the gravity curve just below expected FG, and the chiller’s cooling cycles have elongated and now stopped in response to a drop in yeast activity.

This isn’t unusual in and of itself, but I don’t think I’ve seen it just three and a half days after starting primary fermentation. The successful starter probably had a lot to do with it, so I’m going to flag this as #wisdom and will repeat the recipe (especially the timings) next time around. The only question now is whether I let it ride the full 2 weeks (and cold crash from 2-5 December while we’re away) or do I try to crash for a day and keg it early?

Oct 202126Tue

Both these brews have been chugging along nicely, popping their airlocks every second or so for a couple of days now. Allotment Riot (below left) grew a nice foam hat about 25 hours after pitching the starter, which then covered the entire surface. It’s since thinned out a bit and started to recede as soon as I opened the bucket in order to take this picture.

Allotment Riot (front left) and Best Wellies (front right)
Oct 202126Tue

It’s been a week since I added two Campden tablets to this bucket, and now the airlock is bubbling again. Maybe I should have been quicker to pitch my Kveik but the stir plate has been tied up all this time. What to do now? I don’t want to throw in more Campden and risk the brew tasting of nothing but sulphides, and it’ll be another 2 days before my starter is ready for deployment. Hmmm

Oct 202124Sun

Fermentation picked up well after a day or so of pitching the yeast starter, and the airlock bubbled away happily for 3 days at 1-2 pops per second. Since yesterday it’s slowed down to just 1 pop every 4-5 seconds, so I took a gravity reading: 1.004 for about 8.1% ABV.

The colour’s lovely and the taste … is not bad, but there’s still a strong flavour of grapes rather than wine, and some sourness, although there’s sweetness present too. It’s too sharp for Patience, but I’m happy to finish off the contents of the sample jar without protest.

What to do now? I think that if I stop fermentation with a Campden tablet then we’ll still have the sweetness, but also the slightly sour edge which might translate to a rough finish with ageing. Let’s leave her to it for another couple of days so that the yeast can clear up after itself, even if it means losing some of that sweetness.

Jul 202108Thu

Stepped Fermentation Schedule

This is the first time I’m following a fermentation schedule which increases in temperature towards the end, presumably to aid the yeast in providing a clean finish. Adjusting the temperature has been very easy; just set a reminder on the relevant days and then make a simple adjustment using the Inkbird app, but it’s the impact on fermentation that’s got me puzzled, because things seem to have slowed down just as I started ramping the temperature up.

Sarka 8 days into Primary

My fear is that the change in temperature has somehow flummoxed the yeast and caused it to suspend operations, although most of the Krausen and foam have disappeared instead of stopping dead. There’s still a few tiny bubbles rising up from the Fermzilla’s collection jar, which seems to be half-full of good looking yeast.

Then again …

It might just be the readings from my Tilt. At the start of this brew I noticed that the device was reading 11 points lower than my old-fashioned hydrometer, so I did something that I hadn’t done before and specified an 11 point offset within Brewfather, knowing that this may well give me false readings later on because I’d previously noticed that the margin of error seemed greater at the OG end than FG.

For example, Yeti’s actual OG was 1.073 and Tilt reported 1.058 – 15 points low – but the actual FG of 1.016 is just 4 points above Tilt’s 1.012.

If we apply the same 11 point adjustment to Tilt’s current reading for Sarka, 1.020, we’re actually looking at 1.009, which is exactly where Brewfather said we should be right now and explains the levelling out of the fermentation curve perfectly.

Post-Fermentation Finings

Following this recipe has me doing yet another new thing: adding some Polyclar 730 in order to take care of chill haze, which I believe is caused by the interaction of proteins from the wort with enzymes in the hops. Polyclar’s instructions recommend that a dose between 5-25g per litre be added to secondary fermentation, but because I’m not doing a secondary fermentation I’ll be adding it at the end of primary, just before cold-crashing.

The addition process should be interesting too. I don’t need to dump any trub and I’m not dry-hopping, so there’s really no need to de-pressurise down from my 10 PSI fermentation pressure in order to remove the collection jar. Instead I’m going to draw some wort into a purged PET bottle via the floating dip tube, which will already contain the correct amount of finings in an oxygen-free atmosphere. I’ll give this a shake to mix things up before sending it back into the Fermzilla via the dip tube.

Truth be told I’m not 100% happy with using the dip tube for this purpose, but it’s the only way of doing it without risking oxidation because I didn’t fit carbonation caps to the collection jar. There’s still a couple of days to go until I need to start cold-crashing, so I’ll mull it over, but will probably go with the plan as described just now.

The one thing I do know is that, according to the things I’ve read, Polyclar is made up up plastic micro-beads so I’ll have to find a way of making sure the trub at the end of this brew goes to the incinerator and not into the environment. I only discovered this when researching how to use the product, and probably wouldn’t have bought it had I know about its composition earlier.

Jun 202120Sun

Both the Opshaug Pale and Bure Gold that I’m brewing with my resident Opshaug Kveik are still fermenting when they should have finished out a couple of days ago, though to be fair the trend graphs provided by Tilt Pro are now beginning to flatten out a little so I’m looking forward to getting both of these put away in the coming week.

I don’t pay attention to the absolute values reported by Tilt, but I think it’s safe to say that both of these brews are going to be way stronger than they’re supposed to be; Bure Gold should be around 4.3% (previous efforts were 4.3 and 4.2%) and Tilt thinks we’re nearer 4.6% right now, Opshaug Pale was aiming for 5.3% in the recipe (5.9% adjusted for actuals) and I’m presently in the neighbourhood of 6.7%.

The only negative aspect of this continued fermentation is that my finishing hops will have had their contribution diminished a little due to the production and venting of CO2, but there’s nothing I can do about that now other than record what’s happened and adjust subsequent brews using this yeast accordingly.

#wisdom: I’m not sure if it’s a trait of WLP518 or the way I’ve harvested / re-used it, but my Opshaug Kveik has not started as furiously as expected, and taken much longer to ferment. If the Opshaug Pale turns out well then let’s repeat it, but dry-hop much later.

May 202128Fri

I have just over 25 litres of Vienna Lager in the Fermzilla, and because I don’t want to try bottling carbonated beer later on I’m moving 5 litres into my SS Brewtech Mini Bucket before increasing fermentation pressure in the Fermzilla to 20 PSI.

The idea is simple; gradually reduce pressure over a couple of hours right down to nothing, connect the beer out post to the bucket’s spigot, close the spunding valve and let fermentation push the brew out. I’m hoping that there’s enough yeast in suspension to keep the fermentation going without anything else needed, but if it looks like it’s stalled then I can always move some Krausen across later on as well, or just pitch more yeast. Gravity presently at 1.023 so we’re about 75% complete.

One thing was slightly weird; the hose connecting both vessels seemed to be pulling quite a lot of gas, even though both ends were fully submerged in the brew. I can only guess that this is CO2 being produced by the wort as its inside the tube, otherwise I’ve got a leak and a problem when it comes to kegging from the Fermzilla later on.

15 minutes later: the bucket’s airlock’s bubbling away happily, looks like my little Opshaug friend doesn’t mind his new environment. Pressure going up again gradually in the Fermzilla too – I didn’t want to add CO2 from the tank so as to increase pressure gradually because I’m concerned about the effects of all these changes on the Tilt.

Mar 202110Wed

Airlock activity started a couple of hours after pitching the yeast 2 days ago, and has increased steadily ever since. Right now there’s an audible fizzing coming from the plastic brew bucket and the airlock is popping enthusiastically.

Fermentation of Strawberry & Pear Cider

I used Bag-Thing to harvest some of the CO2 that’s being produced in order to prevent suck-back on Second Blonde which just started cold-crashing. Let’s hope there’s no difference in the CO2 that’s produced by cider and that which comes from beer. Usual sanitation procedures were observed.