Tag Archives: fermentation

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.