Open Fermentation and/or Different Fermenter Geometry.

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Interesting. I picked up the bit about transferring to the secondary before primary fermentation is complete.

Also hadn’t thought about using it for lagers because of the lack of protective krausen. There is a comment about the ester profile which is intriguing. 34/70 at 15c might be ok. 🤔
 
And, if you go hunting for it, there are quite a few references (or at least suggestions) out there that Czech Pilsner is (or was!) traditionally fermented open. I'm sure I saw a fairly recent-ish looking picture the other day of a row of massive open vats at (I think) Pilsner Urquell.

My own notes fermenting Czech Pils with Wyeast 2278 mention a decent measurement forming.

I'm quite interested to try fermenting one open at some point, but for now I'm sticking to what I know works - due to various experiments I keep making mediocre beer lately and I don't want rubbish beer on tap when Xmas rolls around 🫤
 
Bottled them. Both batches had cleared nicely. Now carbing up.

Top image is the open ferment, bottom is closed. I noticed that the closed one foamed when I added the sugar so there must have been more dissolved CO2 in it. I considered that one covered rather than sealed so I wouldn't have thought there would have been any pressure. Maybe it doesn't need much or maybe there's another explanation.

IMG_7697.jpg


IMG_7699.jpg
 
Well. I’ve cocked up the carbonation. Undercarbed but I know why. They pour nearly flat but it doesn’t seem to spoil anything, makes it taste hand pulled. Had a sample of each, there is definitely a taste difference. No spoilers yet as I need to do a side by side.

@Sadfield , do you want to taste them ?
 
Yes.

I've been thinking about the 'under-carbonation'. That's what I thought because it doesn't fizz like I normally make them but there is enough so it doesn't taste flat. So maybe low carbonation is more correct. Do you want to try them @matt76 ?
If you have enough to share, sure, I'd be very interested to try them, thank you 👍I wouldn't inflict my Altbier on you but more than happy to send you something in return 🍻
 
DSC_0065-02.jpeg

Samples A, B and a palate refresher. Not full pints as I wanted to make sure I left yeast in the bottles.

Hopefully the other tasters will post their findings before reading. Cheers for the beers @Twostage.

They're different.

A - Cleaner, less hazy, poured with a slightly tighter head and possibly better lacing.

B - Slightly more aroma, more bitter, more hazy.

My own experience with open fermentation is there's a difference, but its a broad, qualitative difference. Not so much as getting more intense esters, as getting a broader more complex array of esters, using yeasts that express more. Fermentation is better, with less off flavours and less maturation needed, resulting in a better fermented beer. Better clarity. And reduced bitterness through more vigourous fermentation.

Which is which? This is where it gets tricky and where I probably fall on my sword. Tricky because Notty is very clean with very little ester profile, which mitigates some of the advantage of open fermentation. And, also with the carbonation issue, with foam being a carrier for aroma, that might subdue any differences.

Notty.

Flavor-wheel-EN-Nottingham-5.png


My overall impression is that A is the better beer. It's slighly less hazy, cleaner tasting and more balanced, it just tastes like it fermented better. B tastes greener, has a slight green apple aroma and is more bitter. My feeling is that the green apple aroma isn't esters from Notty, but acetaldehyde from fermentation.
So, with trepidation, I'm saying A is open fermented. Less stress on the yeast making a better beer.

Now, off to scrub the marker pen off the vintage glassware.
 
Last edited:
Meanwhile in other news, I brewed another batch of my Hurricane Porter early doors this morning which I'm fermenting open.

I've gone with Lallemand Verdant IPA this time which has served me well in the past for this and other beers, though I don't think I've ever done an open fermentation with it.

My experience is it ferments pretty quickly and reliably though it is said to have a krausen that sticks around a bit so I'll have to keep one eye on that and the other on the Tilt to try and gauge when to put a lid on it.
 
I did yes, thanks very much again for sending. If pushed I would have to say Sample A was the open ferment but I really am just guessing.

View attachment 105638

You might have noticed that @matt76 ’s review was somewhat lacking in depth. He messaged me to let me know they didn’t travel well and were not drinkable and was saving my blushes by keeping it light on detail. Cheers for that. It happens. Anyway time for the results. For me the most important was that there was a difference. The aromas and flavours were not the same. Even the dissolved CO2 was different which is maybe not a surprise but the closed one wasn’t under real pressure. And the samples were :-

A - closed
B - open

Family members preferred the open batch.

IMG_8142.jpeg
 
Back
Top