'open' primary; Fine for wine, why not beer?

Hey folks!

I've been making homebrew for the past two years or so, and I got most of my knowledge from these forums and articles linked from these forums.

Something that is always hammered here is how important oxygen is for primary fermentation, yet its always insisted that primary fermentation be performed inside of closed off csrboys.

So to counter this, we add pure oxygen from a medical o2 tank to help the yeast out.

My question is, why not perform primary fermentation in a giant vat or bucket inside of the fermentation chamber and put a cheese cloth on top as is common in winemaking?

Is beer somehow more vunerable to infection than wine?

No, that would work. But even with wine, once fermentation slows down, it is racked to a carboy and airlocked to prevent oxidation and contamination. Often, for me that is about 5-7 days for wine and it would be even faster for beer.

That's standard practise for English commercial brewers. They use open top fermentation tanks to ferment down to a couple of points above FG, then transfer to casks for secondary/carbonation before serving from the casks, or to secondary tanks for conditioning before bottling.

e.g. Sam Smith's Yorkshire Squares:

Same for SN Bigfoot

I've seen open fermenters in Germany also. I suspect that the rooms that contain these vessels are probably cleaner than my basement.

Open fermentation and requireing oxygen in wort aren't really the same thing. Open fermenters will have a layer of kraeusen and CO2 mostly protecting the beer from oxidation, and O2 needs to be incorporated into the wort through bubbling, swirling, shaking, etc. O2 at the surface is probably not enough to optimize healty yeast reproduction. Otherwise, we wouldn't have to go to so much effort shaking our fermenters, as fermenters, of course, are filled with ambient air.

As Yooper said, wine and beer is typicaly moved to secondary once the krausen has fallen, at some point the exposed surface would be oxidized too quickly.

Open fermentation is a technique to gain a different flavor profile. In Belgium, their "microclimate" is prized, as they know the mixture of yeast, bacteria, etc. that have developed in the coolship / fermentation area make for fantastic beer. Some breweries even plan local plants that they know are brewing friendly. I am skeptical that the typical garage or basement would have such a beer friendly environment. But homebrewing is all about experimenting, this is an interesting variable that can be added to your homebrewing.

Sorry for delayed reply to my own thread guys! Love the examples of actual "open fermentation". I completely agree that once the main part of the fermentation has been completed, the beer should be racked to secondary to allow it to finish. I was mainly wondering why we seem to preach doing primary fermentation in a carboy so much for home brewing, when in wine making that seems to be very rare.

At Cyclman:

I am not advocating an "open fermentation" to get a different flavor profile, I am thinking that if you did your primary inside a vat that is covered with a towel or cheese cloth lets say, you could easily incorporate oxygen into the beer/wort by stirring it with a paddle at any point during primary.

You wouldn't want to add oxygen to the primary after the initial lag/growth phase to avoid staling.

Plenty of belgian brewers, and some American ones, like Jolly Pumpkin and Jester King, do some open fermentations. However, I think they know what they're getting from their local yeast flora. It can certainly be done, but your results will probably be inconsistent at best. There was an article in a recent issue of BYO discussing how to culture wild yeast.

I think the point of the thread has gotten a bit lost, probably my fault for being vague and not listening a motivation for the thread.

I brewed 13 gallons of Munich helles and did my primary fermentation in a 20 gallon vat covered with a towel inside of my fermentation chamber before racking to secondary for a d rest and laggering inside of two 6 gallon carboys. (So while laggering I'd have an honest 12 gallons)

Yes, I pitched lager yeast, but the whole process seemed weird to me based off of everything I read here, but wine maker I've spoken with don't seem to flinch.

I think it was John Palmer in How To Brew who said it but I've read that open fermentation can be done with wine because the pH of fruit juice is much lower than that of mashed grain.

tgmartin000 said:

Plenty of belgian brewers, and some American ones, like Jolly Pumpkin and Jester King, do some open fermentations. However, I think they know what they're getting from their local yeast flora. It can certainly be done, but your results will probably be inconsistent at best. There was an article in a recent issue of BYO discussing how to culture wild yeast.

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:smack:

Open fermentation and spontaneous fermentation are different, although Jolly Pumpkin does both. See the examples already given above for examples of pitched open fermentations.

Wine makers can do an open ferment because they kill everything with sulfite after fermentation is done, beer makers do not.

adrock430 said:

Wine makers can do an open ferment because they kill everything with sulfite after fermentation is done, beer makers do not.

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I digress, if you are having to use sulfites to kill things in your wine you have reached a very very bad stage of wine making. Sulfites are oxidation protection and insurance against bacterial infection in the secondary.

Yooper said:

...once fermentation slows down, it is racked to a carboy and airlocked to prevent oxidation and contamination...

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Would you need to rack to secondary to avoid O2/contaminants in late-fermentation, or could you just throw a lid on your primary fermenter?

So sulfites don't kill everything after the primary then?

i've run four open fermentations not counting intentional wild batches. mine have been the bucket with a piece of muslin overtop, secured with bungee cords or similar. very breathable. of those four batches, two became infected. not severely, but the bottles eventually became gushers. i was pretty careful to seal it up right when the krausen started to fall. YMMV.

i think i'll only try this again if i rig my fermentation chamber to be a negative pressure zone.

Anyone have any luck doing open fermentations with Ringwood? I have heard this method works well for this beast of yeast.

popquizkid said:

Anyone have any luck doing open fermentations with Ringwood? I have heard this method works well for this beast of yeast.

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Ditto, I'm wanting to use this yeast next batch and am really curious about open fermentation.

adrock430 said:

So sulfites don't kill everything after the primary then?

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No, they do not. If they did, winemakers would use them to arrest fermentation instead of waiting for fermentation to stop, the wine to clear, then adding sorbate and sulfites prior to backsweetining.

Sulfites, are more of a "stunner" than they are a stopper.

I frequently do "open fermentation" by using a wide bucket with the lid just loosely set on to prevent bugs and dust from landing in it. It works great for top cropping yeast strains like wy3068 weizen or wy1318 London 3 with relentless krausens that never fall. I'll leave it in the primary for 7-14 days and either skim the yeast or poke the autosiphon through the krausen and rack it straight to the keg.

Can someone please tell me exactly what open fermentation is? Wouldn't fermenting in primary with a bucket instead of a carboy be considered an example?

Palazar said:

Can someone please tell me exactly what open fermentation is? Wouldn't fermenting in primary with a bucket instead of a carboy be considered an example?

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Look back through the thread, it is covered fairly well here.

Primary in a bucket would be open fermentation if there was not a lid sealed on top of it. From this thread and others, it seems home brewers generally use something (towel, muslin bag, etc) to deter contaminants, while allow the wort access to ample oxygen during the early stages of fermentation.