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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.
Are you opposed to open fermentation? You can always do half and half.
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
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.
Mark, any reason you can’t just ferment open in the boil kettle? Just chill with an IC, provide O2 and pitch.
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.
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.
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.
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.
Pellets here. Im a pumper. Plus I feel that pellets stay fresher longer.
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.
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.
Yep. Wort with trub made a clearer, better tasting beer.
Blind triangle test?
With all due respect, then you really don’t know for certain. Not that your opinion doesn’t matter.
Doesn’t the Crabtree effect have something more to do with the production of alcohol due to the concentration of sugars in the media? I’m not really sure.
However, I do agree that the metabolic condition for the yeast under that yeast foam blanket should be primarily anaerobic. I just wonder if there is some sort of effect from micro-oxygenation of the overall system on the yeast?
techbrau, it pays to search before posting. Most of the information that you posted in the last couple of posts has been posted to the forum many times.
You are going to find yourself very frustrated in this hobby. One of the more influential brewers to enter and leave the hobby while I was on hiatus based a huge number of conclusions on one-shot experiments that contained tiny sample sizes. There was no attempt to encourage others to repeat his results. You as well as I know that is not how science works, but many of his results have become gold standards that you will have to work very hard and make many enemies to tarnish.
To be completely honest I had a bit of an ulterior motive when I let Shaken, Not Stirred loose in the community (I started with British brewers first because they tend to be less dogmatic). While I have believed that it is a solid low-cost, low-tech, and practical way to make and pitch a healthy starter for over two decades, I needed to know if the results were repeatable as well as under what conditions did the method not meet expectations. Are there still unknowns? Of course, there will always be unknowns because we are dealing with biological organisms. However, I am now very comfortable suggesting the method to other brewers who are looking for a way to make and pitch a healthy starter that is easy to perform and low cost.
I remember what it was like to be cash strapped when I first started brew. I had moved up to a detached home from a non-detached home a couple of years earlier, and I was still a single man. I was not robbing Peter to Paul like a lot of house poor people, but discretionary income was in short supply. After having lived through that experience, I did not want see a single new brewer put off moving up to using liquid cultures because he/she could not afford to purchase a stir plate and an Erlenmeyer flask when I knew that they were not necessary to propagate yeast.
With the above said, you will find that even the most technical brewers in this hobby are not pure scientists because most have an engineering bent, which means they are practitioners just like medical doctors where their worlds are combination of theory plus practice. You will not find much in the way of support for basic science without an immediate application within the community, and most of the basic science that is conducted will be inherently flawed due to small sample sizes and poorly designed experiments. It is just a fact of life.
I am talking about the Crabtree effect. The gravity at which the Crabtree effect kicks in, which you probably copied from somewhere else without understanding how the 1.008 figure was calculated and under what wort composition. I laid these numbers and calculations out in several threads in such a way as to be accessible to the layman. O2 solubility with respect to gravity as well as the importance of cellular health and increased pitching rates with high gravity wort due to the effects of osmotic pressure and ethanol on turgor pressure has also been covered several times with supporting citations. You are acting like this information is new to everyone.
The AHA Forum is not a tech journal. It is a hobby site with people with disparate backgrounds. What you call hand waving is an attempt to make the complex information accessible without bogging people down. Finding the balance between what is and is not too nuts and bolts is an art form.