[techbrau]

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[hopfenundmalz]

I used sterile filtered air on a batch of saison in the conical. No airlock, that is where the air went in, the gases exited through the the pressure relief, which was removed, and the hole was covered with AL foil.

Seemed to work just fine.

[S. cerevisiae]

Are you opposed to open fermentation?  You can always do half and half.

[S. cerevisiae]

Why leave the lid on at all?  Microflora rides through the air on house dust.  House dust is not entering an active fermentation due to the fact that it is under positive pressure.    All you need to do is to leave the lid on until the fermentation starts outgassing, and reinstall it when the fermentation dies down.


I am open fermenting another batch as we speak.  Here are the photos from my last batch:

Pre-brown head removal



Pre-yeast skim



Post-yeast skim

[S. cerevisiae]

I am using a non-modified Vollrath Classic stainless steel stock pot as an open fermentation vessel.  I like Vollrath stock pots because they have welded handles.  Vollrath sells this particular model as a 24 quart stock pot, but it is actually closer to 6.5 gallons.  My standard primary batch size is approximately 3.5 gallons.  I used to use a non-modified 38.5 quart Vollrath Classic stainless steel stockpot as an open fermentation vessel when my standard primary batch size was 5.5 gallons. The beauty of using a stock pot is that it can be steam sanitized by filling it with a quart or so of water, affixing the cover, and placing it on the stove.

I do not rack to a keg when open fermenting.  I rack to a carboy for maturation shortly after I skim the final head.   The O₂ bogeyman is just that, a bogeyman.   Any O₂ that is picked up during the transfer is rapidly scrubbed from the wort by the remaining suspended yeast cells.  O₂ pickup only becomes a major problem after filtration or long periods of cold conditioning.


The yeast strain in the photos is NCYC 1333.  I acquired it on slant from the National Collection of Yeast Cultures (NCYC) in the Norwich, England.  It is a Yorkshire square strain of all things.

[neddles]

Mark, any reason you can't just ferment open in the boil kettle? Just chill with an IC, provide O2 and pitch.

[S. cerevisiae]

I personally do not want all of that trash in my fermentation vessel.  I leave almost all of the hop material and most of the break in the kettle.

[neddles]

Trash? Interesting. I am not convinced it makes any difference being in there but you could simply chill, let it settle and siphon off a half gallon from the bottom to get most if not all of it out. The opposite of what a lot of brewers do when they rack to the fermentor and leave a half gallon of the trub and hops behind in the kettle.

[beersk]

I've fermented with all the trub and hops in the boil kettle and I don't feel it negatively affects the beer. It's my recent pumpkin oktoberfest and I actually feel it's one of my best beers brewed to date. I think it's a personal preference, honestly.

[S. cerevisiae]

Separating the bitter wort from the trash may not make a difference your brewery and those of many others, but I have found that it does in mine.  It is not so much the break as it is the hops.  They often to leave a harsh edge that takes a while to age out.  Like Marshall, I ran side-by-side comparisons, so could be certain that I had positively identified the culprit.  I only rack when I use pellets.  I use a false bottom and the ball valve on the kettle when using whole hops.    I also crop as a standard practice, and most beers are bottom cropped, so leaving as much of the break behind with the hops has an added benefit in my brew house.  When it comes to bottom cropping, garbage in, garbage out.

[klickitat jim]

Pellets here. Im a pumper. Plus I feel that pellets stay fresher longer.

[beersk]

I'm a big fan of whole hops as well, mainly because of how they make trub separation easier. In addition to not contributing sludge like pellets do, whole hops in my system tend to trap a lot of the heavier break material at the bottom of my kettle. I still use a siphon to rack to my fermenter, but I'd like to mount a welded nipple for a ball valve and spigot at some point.

Count me as one who can also taste the difference between clear wort into the fermenter and trubby wort. Even in Marshall's experiment he noticed a difference as well.

He said he noticed a difference, but it was negligible. I think prefermentation wort it doesn't matter. What matters is what the yeast eats and what is left over after it's done eating. All that trubby sh*t settles out and isn't in the final beer.

[mabrungard]

Is there any guidance as to which yeast variants are more likely to benefit from more aerobic conditions and which benefit from anaerobic?

I've always conducted sealed (anaerobic) fermentations, but I know that I could easily pump sterile filtered air into my fermenter headspace for the yeast variants that benefit from it.

[denny]

Count me as one who can also taste the difference between clear wort into the fermenter and trubby wort. Even in Marshall's experiment he noticed a difference as well.

Yep.  Wort with trub made a clearer, better tasting beer.

[denny]

In that one particular batch and to Marshall's particular palette. I've tried it both ways myself and prefer less trub.

Blind triangle test?