Saison, yeast, and pressure

I've been thinking recently about trying my hand at a few different Saison recipes, and, what would you know, the current issue of Zymurgy features an article on the style by Drew Beechum.

I found the article generally insightful, but I was puzzled by one thing in particular. Beechum writes that Saison yeasts "cannot handle pressure. Conducting your primary ferment with a covering of sanitized foil keeps the pressure down and the yeast happier..."

Can anyone clarify this for me? What "pressure" is actually involved here?

Also, this foil-covering method, is it a common practice? Is the foil perforated to allow gas to escape, or just fitted on loosely?

Pressure because of an airlock? I call BS...

I've used foil on my better bottles for a long time, but I can't for the life of me imagine that there's any real environmental difference from a bubbler airlock.

Howdy,

I don't have my notes in front of me, but that little tidbit came straight from one of the yeast doctors. It does seem to back up some of what my experiments with pressure capping batches show. Regardless the Dupont strains can be finicky until you get into a zen lock with them.

-- Drew

Honestly, for about a year now I've been itching to get one of those polycarbonate long flat food containers. About 5 gallons takes up less than 4 inches in height, I would love to see how a saison under such miniscule pressure would turn out. I think it would be amazing.

dbeechum said:

Howdy,

I don't have my notes in front of me, but that little tidbit came straight from one of the yeast doctors. It does seem to back up some of what my experiments with pressure capping batches show. Regardless the Dupont strains can be finicky until you get into a zen lock with them.

-- Drew

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Definitely, and I don't doubt that pressure is a big part of that finickiness. Still, like DannPM alludes to, I've got to think that fermentor geometry impacts those pressure dynamics by orders of magnitude beyond what the presence or lack of an airlock does. I certainly could be wrong, but as far as I can tell the pressure differential only needs to become trivially small before the chamber starts bubbling.

Agreed, geometry is key. When I last saw dupont's system, they used big squares.

Since most homebrewers aren't going to have access to different geometry shapes, the easiest thing they can do is eliminate any back pressure within their standard control.

DB, I beg to differ, these containers are about as much as a carboy ($50 with lid) as an example here. You could drill a hole for the airlock without spending more than maybe $5 on a drill bit and you've got a super shallow ultra low pressure fermentor for ~$55

Now you've got me badly thinking I want one of these again damn it!

Another advantage is that the beer will clear faster as well since the yeast only has to drop ~4 inches vs well over a foot with the standard carboy!

Oxidation might be a problem with such a large surface area. You'd want to get it into secondary or bottle keg or whatever pretty much as soon as fg was hit.

There would be quite a co2 blanket over it and if you're really concerned you could flush with some co2.

If it's in a long container that magic blanket would probably be easily removed, the whole idea is not to have any pressure on the beer so I'd assume there wouldn't be much to stop the co2 being removed by changes in the ambient pressure or even light gusts near it.

I just don't see how you would remove all that co2 from fermentation unless you taking off the lid off for those light gusts to even touch it. I would think racking it to a secondary would provide more oxygen exposure. How does the co2 escape and get replaced with oxygen in a sealed airlocked container?

I'm not trying to argue I'd honestly like to just see any downside to this before I blow $50 on this. I wanna vet your counterpoint lol

My point for a long flat container is that the pressure of the wort from the depth is greatly reduced along with the saturated co2 in the wort escaping more easily, not the co2 in the airspace.

Think of going underwater. Remember as a kid going to the bottom of the deep end 14 feet underwater? The pressure would make my ears pop and I would feel heavy. Now think of going underwater in an equivalent amount of water volume spread out to a depth of 1 foot. Almost no pressure felt at all!

I would think the pressure to bubble through the airlock itself would probably provide on either system the equivalent of a cm or two of equivalent pressure added volume to the wort.

No reply? Lol

Huh?

I don't think the pressure you'd get in a 5 gallon bucket or carbuoy or whatever would be sufficient to change the beer. Maybe you'd be just as well off doing an open fermentation.

Also keep in mind the yeast won't be fermenting on the bottom of the vessel.

DannPM said:

I would love to see how a saison under such miniscule pressure would turn out. I think it would be amazing.

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Maybe you could do a test- ferment one batch on the roof of the highest building in town, and another in the basement. The further decreased pressure could make the roof top batch even more amazing. No more absurd than foil vs. airlock, or 4" vs. 16" deep vessel causing a meaningful pressure difference.

I'm sorry but if you think fermentor geometry doesn't make a difference you've got a lot to relearn about brewing dude lmfao!!

Is the author trying to say that an airlock actually raises the pressure in a fermenter? I sure hope not, because that would be quite laughable. If the yeast are pressure-sensitive, then a better question would be "is 16 inches of liquid too much pressure on the yeast?" To answer that, check what the breweries are doing... are their fermenters shallower than 16"? I'm guessing, but that seems very unlikely. So I can't imagine a 4" fermenter would make a difference for us.

I am going to go out on a limb and guess Brasserie Dupont and others are not fermenting in 6" fermenters, I am going to guess they do in fermenters deper than a carboy.

DannPM said:

I'm sorry but if you think fermentor geometry doesn't make a difference you've got a lot to relearn about brewing dude lmfao!!

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I haven't brewed a "dude lmfao" yet, so I can't relearn it. Sounds terrible tasting, though.

I never said geometry doesn't make a difference. I clearly stated that at the scale of your examples, the effect on pressure is negligible, and for airlocks it is even more so. Differences in geometry, regardless of pressure, for those examples would probably have little noticeable effect either, but that is not as cut and dried as pressure. You have a lot to relearn, or possibly just learn, about physics (and geometry).

The difference between a 20ft tall conical and an equivalent volume 4ft deep vat is one thing. Going from 16" in a carboy to 4" in a food tote is another. Perhaps you could provide details of your theory and some hard numbers.

In case anyone is interested.

Belgian beer and travel: Brasserie Dupont article in Taps: The Beer Magazine

I'm not going to go search for you, but listen to jamil, doc, and palmer on the bn. There have been several references about how brewing a 2.5 gallon batch in a 5 gallon carboy produces a different beer than filling it with a 5 full gallons due to differences in pressure on the yeast.

Sorry sport but I tend to put just a little more faith in what those guys say than some rando on hbt.

DannPM said:

I'm not going to go search for you, but listen to jamil, doc, and palmer on the bn. There have been several references about how brewing a 2.5 gallon batch in a 5 gallon carboy produces a different beer than filling it with a 5 full gallons due to differences in pressure on the yeast.

Sorry sport but I tend to put just a little more faith in what those guys say than some rando on hbt.

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Man...

Fact-wise, I actually agree with you, but you really seem to be going out of your way to come off as unpleasant.

MalFet said:

. . . but you really seem to be going out of your way to come off as unpleasant.

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Agreed.

MalFet said:

Man...

but you really seem to be going out of your way to come off as unpleasant.

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And that's a very pleasant way to put it.

As to TBN they quote that most Belgian Brewers as accepting a 1:1 ratio. The only two Breweries that I've been to in Belgium (Deca and Cantilion) were open air and weren't 1:1, they were wider and more shallow. But the TBN also quote Vinnie as saying that once he learned how to manipulate his yeast that the special fermenter was no longer needed. So they seem to be saying that fermenter dynamics can be trumped. TBN also talks about dead zones in the corners and 90* angles. The fermenter proposed is so shallow it looks like one huge dead zone. I might not be and there is only one way to find out. Brew with it and do blind tastings with other more traditional processes.

DannPM said:

I'm not going to go search for you, but listen to jamil, doc, and palmer on the bn.

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I am not a member of that cult, so I don't just assimilate their programming. I have heard many incorrect things stated by all of them, but one more so than the others. They have all backpedaled on various issues when challenged. I'm not going to search for you, but believe the facts, not the propaganda.

DannPM said:

There have been several references about how brewing a 2.5 gallon batch in a 5 gallon carboy produces a different beer than filling it with a 5 full gallons due to differences in pressure on the yeast.

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If you really believe that strongly that it is the pressure, I implore you, again, to immediately find the nearest 50+ story building, and rent a penthouse suite for your fermenting chamber. Your beer is suffering.

I realize Kansasinians are elevationally challenged, so finding a hill to ferment on is not an option if funds are an issue. In the meantime, you could make do by limiting yourself to only brewing during low pressure fronts. Stop yeasticide!

DannPM said:

Sorry sport but I tend to put just a little more faith in what those guys say than some rando on hbt.

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Faith is an interesting word choice. Why not prove your point with some numbers. Read up on stuff by "rando" guys like Newton, Maxwell, and especially Pascal (the SI unit of pressure is even named after him, can any of the BN talking heads match that level of street cred?).

I don't doubt that a 2.5g batch could taste different than a 5g batch fermented in the same carboy shaped/sized container, but pressure is not one of the causal factors. Pressure is also not the only geometry related side effect to shallow fermenters.

My question to you is whether you heard the news that they are counting posts in the OT areas again? The Never Ending Word Thread still works to bump your post count.

Yes the cult of the three time-Ninkasi winner and the man who literally wrote the book on how to brew. Of course you know more than them.

And please stop with the utter ridiculousness of fermenting on the top of a building and learn your facts before you start your internet flaming. Sea level or 1000 feet above sea level, you're still getting roughly 100 kPa either place. Geez

Dude, if it makes you happy and you really want to try it, go for it.

I'm not convinced it'll make a hugely noticeable difference but worst case scenario you've got another fv. You could always get another 5 gal fv and split it if they say that made a difference?

DannPM said:

Yes the cult of the three time-Ninkasi winner and the man who literally wrote the book on how to brew. Of course you know more than them.

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From guys who were literally around before they could win Nobel prizes in physics, here are some numbers for you:

0.43psia/1' of wort
16" wort (carboy) = 0.57psig
4" wort (food tote) = 0.14 psig
0.1' of wort = 0.043psig (airlock pressure increase)
0.8psid High to low pressure front variability (14.2 -15.0psia) (29-30.6inhg)
~0.5psia/1000' elevation gain
~0.25psia/50 stories

All converted to psi for your convenience. It should be easy enough to connect the dots.

DannPM said:

And please stop with the utter ridiculousness of fermenting on the top of a building and learn your facts before you start your internet flaming. Sea level or 1000 feet above sea level, you're still getting roughly 100 kPa either place. Geez

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You are contradicting yourself. At first, tiny pressure variations are immensely important. Then a 1000' elevation gain, which is a greater pressure difference than between a carboy and your food tote, is "roughly" the same. If you have a case for fermenting at 4" vs. 16" of depth, stating the basis behind it would help. Maybe you could start a whole new movement- fermenting under vacuum.

You just can't let it go that you're wrong can you? Lol

DannPM said:

You just can't let it go that you're wrong can you? Lol

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I am not saying anyone is right or wrong, just trying to help you make your beer more amazing. You keep saying that pressure is the critical factor. So much so that the difference between a 16" and 4" depth fermenter is crucial. I only provided some suggestions- like fermenting on the top floor of a building or during low pressure fronts- that would exactly mimic the pressure difference. You could save yourself the $50 for the new vessel, or do both and double the improvement. Just think how exquisite the flavor could be.

These suggestions were based on some numbers I came up with based on your scenarios, but only because you have yet to provide any numbers yourself. Are you saying that my numbers are incorrect?

Others have questioned this as well, and asked for more specifics, but none have been provided. One person has even questioned the other effects of the geometry of your dream vessel, and again no response. Wasn't it you that earlier wanted critiques of your theory, and taunted your opponents when none responded?

DannPM said:

I'm not trying to argue I'd honestly like to just see any downside to this before I blow $50 on this. I wanna vet your counterpoint lol

My point for a long flat container is that the pressure of the wort from the depth is greatly reduced along with the saturated co2 in the wort escaping more easily, not the co2 in the airspace.

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DannPM said:

No reply? Lol

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