Breathable Airlocks??

[RedEagle]

Has anyone used these? I'm looking into them so I can use an old mini-fridge as a fermentation chamber. Traditional airlocks will be too tall. Thanks in advance!!

https://www.morebeer.com/products/carboy-bung-silicone-breathable.html

 

[doug293cz]

Silicone elastomers have the highest O2 permeability of any of the commonly available plastics. They should be avoided if you are trying to avoid all O2 exposure. In cases where active fermentation is occurring, the CO2 being generated will sweep most of the O2 (that diffuses in thru the silicone) out of the vessel. Long hold times after active fermentation ends will allow O2 to build up in the headspace (and diffuse into the beer.)

Brew on

 

[RedEagle]

Silicone elastomers have the highest O2 permeability of any of the commonly available plastics. They should be avoided if you are trying to avoid all O2 exposure. In cases where active fermentation is occurring, the CO2 being generated will sweep most of the O2 (that diffuses in thru the silicone) out of the vessel. Long hold times after active fermentation ends will allow O2 to build up in the headspace (and diffuse into the beer.)

Brew on

Thanks for the explanation! I don't have room to fit an airlock in but I think I can squeeze a blow off tube in there. Guess that's the route I'll take.

 

[Vale71]

A silicone hose used as a blow-off will be even worse because of the larger surface area.

 

[jrgtr42]

Something like those silicone caps will be fine for primary fermentation. If you rack out soon after it's done, you should have minimal issues. If you store or age the beer, a solid bung would be a better choice.

 

[RedEagle]

A silicone hose used as a blow-off will be even worse because of the larger surface area.

All of my tubing is vinyl.

 

[RedEagle]

Something like those silicone caps will be fine for primary fermentation. If you rack out soon after it's done, you should have minimal issues. If you store or age the beer, a solid bung would be a better choice.

I don't generally age my beer other than a few big stouts or the occasional barleywine. I suppose after fermentation is complete I could replace with a solid bung if I'm doing some secondary conditioning/additions.

 

[Knightshade]

maybe something like this is an option?
https://www.morebeer.com/products/blow-tube-stainless-12.html

 

[RedEagle]

maybe something like this is an option?
https://www.morebeer.com/products/blow-tube-stainless-12.html

I use a Catalyst for fermentation so I don't think that will fit across the lid. I'll have to measure it out. BUT that does give me some more ideas!! Thanks!

 

[Knightshade]

I use a Catalyst for fermentation so I don't think that will fit across the lid. I'll have to measure it out. BUT that does give me some more ideas!! Thanks!

Nice. I think I've seen people repurpose stainless steel racking canes..and pick up tubes to great effect with a bit of additional tubing. I actually had the same issue with a Speidel and its gargantuan airlock not going to fit in my FC. I ended up purchasing something from Norcalbrewingsolutions, who unfortunately in your case doesn't make stuff for catalyst fermenters.

 

[Craiginthecorn]

For primary fermentation, just cover loosely with a piece of sanitized aluminum foil. The CO2 production is massive and will push out any bugs thinking about getting in. The foil will prevent anything from just falling in, especially when fermentation slows. I do this all the time with backpressure-sensitive yeasts, like the Dupont Saison strain with absolutely no issues. Anchor Brewing still uses open fermentation, BTW.

 

[Vale71]

The only issue would be the oxygen in the headspace. That with the Dupont strain is just a myth by the way.
Sure many breweries still do open fermentations but they follow a strict schedule were the beer gets transferred to a pressurized, purged maturation vessel for spunding as soon as the Kräusen start falling so that the beer still has no contact with oxygen. This obviously works best with top-cropping yeasts.
If you, like many homebrewers do, leave your beer for several weeks in the fermenter you will inevitably experience massive oxidation without an effective airlock.

 

[VikeMan]

That with the Dupont strain is just a myth by the way.

That's what I think. I've always maintained that the pressure thing with Dupont is a red herring, invented to make people who experience "the stall" feel better. I've used the Dupont strains, alone and in combinations with each other, many times, but most often the dreaded 3724 by itself. It's certainly (generally) a slow strain, but I've never experienced a true stall.

Make an appropriately sized starter, targeting 0.75M cells/ml/°P. Oxygenate the wort with pure O2. Use a nutrient like Wyeast nutrient blend. That's what I do and I have never had an issue.

A physicist on one of the other forums computed that if the height differential of the water in an airlock is 1 inch, then the pressure differential between the gas in a carboy and the air is only ~ 1/400 of an atmosphere.

One last data point... I've also carbonated beers with 3724 with sugar in the keg to 3.9/4.0 volumes. At 70F, that's working against a pressure of over 50 PSI at the end. This should be no surprise really, since Dupont does something similar in bottles.

 

[Deadalus]

I use a stainless steel blowoff tube in my carboys in order to fit in the mini-fridge I have. They are angled specifically for glass carboys. There are SS blowoff tubes for buckets too. I bought a pack of three to use on my bucket and fustis. What I found was that while the angle was better for a flat top, they don't stretch far enough to cover the distance from the interior of the lid top to as an example a grommet centered in the lid. However, I have added a thermowell to my bucket (and will do so on the fusti lids) so I just put the thermowells in the original grommet holes and then added a new hole closer to the side for a grommet for the blowoff tube/airlock. It's not particularly necessary to have the blowoff tubes on my bucket or fustis when using the mini-fridges as they are shorter than the carboys but the holes were too close to the middle to use the SS blowoff tubes.

Note the main difference between the carboy blowoff tubes and the bucket ones I have are that the bucket ones have less horizontal travel and are shorter vertically. Perhaps there are different manufacturers so what you want with a flat lid is something that has a flatter angle and some horizontal travel. The smaller, lower one is the "bucket" blowoff tube.

 

[RedEagle]

I use a stainless steel blowoff tube in my carboys in order to fit in the mini-fridge I have. They are angled specifically for glass carboys. There are SS blowoff tubes for buckets too. I bought a pack of three to use on my bucket and fustis. What I found was that while the angle was better for a flat top, they don't stretch far enough to cover the distance from the interior of the lid top to as an example a grommet centered in the lid. However, I have added a thermowell to my bucket (and will do so on the fusti lids) so I just put the thermowells in the original grommet holes and then added a new hole closer to the side for a grommet for the blowoff tube/airlock. It's not particularly necessary to have the blowoff tubes on my bucket or fustis when using the mini-fridges as they are shorter than the carboys but the holes were too close to the middle to use the SS blowoff tubes.

Note the main difference between the carboy blowoff tubes and the bucket ones I have are that the bucket ones have less horizontal travel and are shorter vertically. Perhaps there are different manufacturers so what you want with a flat lid is something that has a flatter angle and some horizontal travel. The smaller, lower one is the "bucket" blowoff tube. View attachment 688671

I hadn't really thought about drilling another hole for just the blow off tube. That may be my best option. I'll have to get everything in the fridge and do some measuring to see how that would fit if at all. Thanks for the input!

 

[Deadalus]

If you think you need the measurements I'd be willing to measure these out. It's a pretty small vertical rise though because you can push the end in as far as the bend but I only looked briefly at a picture of your fermenter and its lid. I have two fustis, one already had a grommet hole drilled. When I got the second one, it wasn't drilled and I hadn't bought the bucket sized tubes yet so I just drilled it similar to the first one. If I gave it any thought at the time I just figured I would be getting the bucket tubes but not knowing their dimensions I was thinking they would just be flatter angled. It turned out that the grommet holes were too far from the edge. I wanted to add thermowells though and since the flat lid doesn't use a cap or stopper I went with adding a hole.

Point being, if you decide to go this route, don't drill your lid until you have the actual tube(s)!