Fermenting without an airlock?

[Beer Viking]

I've only made 3 batches so far and they have all been from kits but I have been doing so with the lid on the primary fermenter with a garbage bag over it. I have not had a problem with infections and I know a couple people who do it this way. Is there always a risk of the batch becoming infected if I keep doing it this way instead of getting an airlock?

 

[DuncB]

I just used to put the lid on loosely when the ferment was really active and then just leave it a crack open when it slowed down. That was in my beer kit days. Reasonably easy to put a hole for a bung in the bucket lid and put an airlock on though. Nice visible sign to show something is happening and reduce the urge to peek in.
Some breweries ferment completely open with no cover on at all, but they've only been commercially successful for a couple of hundred years.

 

[JWWard03]

I would think it all depends on the area you are fermenting in. If it's a clean area with no bugs it should be fine. I have a lot of gnats, flies and mosquitos in my area so an airlock or vented lid is a must for me.

 

[Genuine]

The idea of a closed/vented fermentation is new in the world of beer history. I have a friend that just places foil on his carboy for the first few days of fermentation before switching to an airlock. Also, there once was a fermenter design with MiniBrew where their lid was just placed on top with no clamps...and an airlock.

 

[madscientist451]

Some commercial breweries use open fermentation, but some of them probably use pasteurization somewhere in their process in order to maintain a shelf stable product.. Is there a chance you'll have some kind of infection? Sure there is, but if you consume all your beer pretty quickly, you probably won't notice any issues.

 

[tracer bullet]

I guess given the cheap cost of a stopper and a hose, and what we are learning about oxidized beer, I'm not sure I'd be a fan of open fermentation. But sure it'll work and not kill you. If you like the results, keep on keepin' on.

 

[Craiginthecorn]

I guess given the cheap cost of a stopper and a hose, and what we are learning about oxidized beer, I'm not sure I'd be a fan of open fermentation. But sure it'll work and not kill you. If you like the results, keep on keepin' on.

Some strains, like the DuPont saison strain, are said to be extremely sensitive to pressure and that open fermentation is best for those strains.

 

[hotbeer]

There will always be a danger of contamination no matter what you do. Some people can get away with things that others can't because of other details that may never be known or realized.

Everything more than just putting a lid on the pot is just extra insurance. How far do you want to go toward insuring no contamination?

I do currently go for closed systems with bubblers or airlocks. Though CO2 is heavier than O2 so CO2 should be laying on the ferment, unless you take the lid off too often and the currents carry O2 down into your beer. And possibly other little beasties and flavors.

Just for full disclosure....

I'm a newb and haven't even tasted my first beer yet.

 

[tracer bullet]

Though CO2 is heavier than O2

It is, but they mix very quickly even without disturbance. The CO2 blanket is a myth. It makes sense it could exist, but it doesn't. Note that on earth you can breath O2 right at ground level, and we aren't in a mile deep blanket of CO2.

 

[hotbeer]

It is, but they mix very quickly even without disturbance. The CO2 blanket is a myth. It makes sense it could exist, but it doesn't. Note that on earth you can breath O2 right at ground level, and we aren't in a mile deep blanket of CO2.

That's true. But the ferment is giving up CO2 and replacing or at least diluting the ratio in favor of CO2. So keeping the lid on will help prevent the mixing. And the CO2 produced by the ferment will dilute that O2 in the air that leaks in.

People have been fermenting successfully in open systems for a long time. So if it works for them and that's what they want, then I see no reason for them to change.

 

[Beer Viking]

I want to lager all of my beer for at least 3 months, if there was an infection would my beer be ok when it is done lagering? If there is an infection i'd be able to tell during primary fermentation right?

 

[Dr_Jeff]

If there is an infection i'd be able to tell during primary fermentation right?

Not necessarily.

 

[VikeMan]

Some strains, like the DuPont saison strain, are said to be extremely sensitive to pressure and that open fermentation is best for those strains.

The pressure added by the liquid in an airlock is less than 1/400 of an atmosphere, according to one physicist I trust. This is less than random fluctuations in atmospheric pressure. The whole DuPont strain being pressure sensitive thing was based on a blog post by someone who really should have known better.

I have naturally carbonated with Wyeast 3724 (the Dupont strain claimed to stall because of pressure) to ~4 volumes, which means at room temp the pressure ramped up to over 50 PSI.

 

[tracer bullet]

That's true. But the ferment is giving up CO2 and replacing or at least diluting the ratio in favor of CO2. So keeping the lid on will help prevent the mixing. And the CO2 produced by the ferment will dilute that O2 in the air that leaks in.

People have been fermenting successfully in open systems for a long time. So if it works for them and that's what they want, then I see no reason for them to change.

Re-reading again I am seeing that the lid is "on"... I didn't quite picture it the first time. So I guess it's on, but not tight, and can occasionally burp? If so then yeah this should be fairly OK and agreed that little O2 will get in. if it's generally sealed

If there's a constantly open air gap, like the lid is sort of on but pushed to the side a little, which is what I originally pictured, then I'll maintain O2 is constantly mixing in. This may not be what was described though.

I think we both agree that if the brewer likes the results, they should keep going with their process. Just hope they understand the effects of O2, and don't come back later wondering why their NEIPA doesn't taste how they wanted it to.

 

[InspectorJon]

The previous owner and brewer at Mad River Brewery in Northern California was a relative of a close friend of mine. We toured the brewery one time several years ago. He showed us his open fermenter where they brewed beer for many years. He said he stopped doing that after one batch got infected and he couldn't support the financial risk of that happening again. So one batch in several years, it could happen.

Then there are the fans of wild fermentations. I'm not one.

 

[Craiginthecorn]

The pressure added by the liquid in an airlock is less than 1/400 of an atmosphere, according to one physicist I trust. This is less than random fluctuations in atmospheric pressure. The whole DuPont strain being pressure sensitive thing was based on a blog post by someone who really should have known better.

I have naturally carbonated with Wyeast 3724 (the Dupont strain claimed to stall because of pressure) to ~4 volumes, which means at room temp the pressure ramped up to over 50 PSI.

My understanding is that the "saison stall" is just a pause. After a period of many days, it is said to resume fermentation, completing with normal levels of attenuation. Your 4 volumes of CO2 is not inconsistent with that.

Here's a link to the article by Drew Beechum (the guy who should have known better) on the topic and is based merely on substantial empirical evidence. He offers no scientific explanation. Folks can decide for themselves what they want to make of it. I have no strong opinion on the matter, but have followed Drew's suggested regimen many times and have never experienced the "saison stall". Brülosophy has done one experiment attempting to prove the theory. It was inconclusive.

https://www.maltosefalcons.com/tech/guide-saisons-and-saison-yeasts

 

[VikeMan]

My understanding is that the "saison stall" is just a pause. After a period of many days, it is said to resume fermentation, completing with normal levels of attenuation. Your 4 volumes of CO2 is not inconsistent with that.

Except that the pressure gauge on my keg climbed steadily over the entire time it took to carbonate. There was no stall. Nor have I ever had a stall in any of my Wyeast 3724 or WLP565 fermentations. So my own substantial empirical evidence is quite the opposite.

Brülosophy has done one experiment attempting to prove the theory. It was inconclusive.

The in process gravity checks by Brulosophy were not inconclusive, except insofar as n=1. But they were clearly contrary to the claim.

 

[Craiginthecorn]

The in process gravity checks by Brulosophy were not inconclusive, except insofar as n=1. But they were clearly contrary to the claim.

I believe what VikeMan is referring to with "n=1" is there was only one split batch exbeeriment, so the test sample population was only 1. One with an airlock and the other with just some foil. On this occasion, no stall was observed and in fact, the airlock sample actually finished a couple points lower. However, the claim is not that the saison stall always happens when using an airlock --only that it was much more likely. Thus, a single example of a non-stall isn't particularly meaningful. I do think that VikeMan's experience fermenting under quite high pressure is equally interesting.

Here is an episode of Experimental Homebrewing where Marshall Schott of Brülosophy and another tester reveal their results. Spoiler alert...The other tester experienced a significant stall using the airlock.

I certainly can't prove the validity of Drew Beechum's theory any better than he can. I'm only sharing what others have experienced and reported. I'll leave this discussion with Mark Schott's observations about his failed/inconclusive exbeeriment, which seem totally reasonable to me:

The results of this xBmt prove one thing definitively…

Drew is wrong and his brewing advice should be purged from the minds of anyone he has brainwashed into believing him.

Of course this isn’t true, Drew is a great guy with oodles more knowledge on brewing Saison than probably anyone I know. I’m not sure why neither of my beers experienced the oft reported Dupont stall or why the airlock beer attenuated slightly more than the foil batch, it could be that I just got lucky, or more likely some other factor that I’m unaware of was at play. Regardless, I’m inclined to view the method Drew proposes as an easy way to decrease the risk of a stalled ferment when using the Dupont strain.

 

[odie]

I quit using airlocks a couple years ago...I just snap a basic lid on the bucket and barely crack the edge in one spot so the pressure doesn't blow the lid off...after a couple days I fully snap it and it's fine.

 

[Birrofilo]

Spontaneous / open fermentation and no airlock are two different things IMO.

If you let the wort open to the air, that's open to insects, bacteria, yeasts in the air. The result might be interesting but not necessarily predictable.

If you let a cap on the fermenter, that will prevent insects, bacteria, yeasts in the air to get in touch with the wort. The pressure created by the fermentation will make the CO2 escape but the movement should be one way, a bit what happens in hospitals where they have positive pressure rooms, what happens in your kettle when the vapour lifts the cap and makes it grumble, or what happens in your Fido jar (or in a Grolsh bottle) when excess pressure is vented outside by some leakage, because the CO2 overcomes the spring of the cap (that makes Grolsch bottles very safe in respect to the risk of explosion. They will not explode, they will vent).

A decently heavy cover on a silicon gasket will decently protect your beer and will "leak" some CO2 during fermentation.

An airlock is a more elegant and precise solution, but it's not strictly necessary. Just like you can ferment Sauerkraut with or without an airlock and without infections, so you can ferment beer with or without an airlock. It's the leakage of your cap which will vent the CO2.

Yet, if the CO2 displaces even a little bit the cap and the "seal" is not maintained, then you could have air entering in.

 

[Birrofilo]

It is, but they mix very quickly even without disturbance. The CO2 blanket is a myth. It makes sense it could exist, but it doesn't. Note that on earth you can breath O2 right at ground level, and we aren't in a mile deep blanket of CO2.

Although I am not convinced about CO2 mixing without disturbances, if we are talking here about a continuous flow of CO2 coming from the beer, that should certainly displace air. When fermentation ends, then one might say that CO2 is equally mixed with the air which gets inside the fermenter. And without an airlock, how can one say precisely when fermentation ends?

This old German documentary on large-scale beer production shows at 8:50 how the flame of a candle, put near the wort, when lowered is extinguished by the high CO2 levels near the fermenting vessels (which are open). The documentary is interesting in itself, and it shows the decoction method employed by the typical brewer of the time.