Is an airlock really necessary?

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Beerbeque

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Is an airlock really necessary or is a piece of plastic or foil over the carboy mouth sufficient? I mean after the blowoff period of course. After that, isn't their a layer of CO2 covering the beer to protect it anyway?
 
Assuming you don't have blowoff, tinfoil works just fine. I can attest to that 100%.

Plastic wrap, I don't trust. Tinfoil, on the other hand, works like a champ. I stopped using airlocks on everything but buckets a while ago.
 
Stand back, I'm going to try Science:

The bacteria we're all afraid of is not the well equipped army we all imagine them to be. They don't have aircraft, boats, choppers, troop transports, tanks, etc... They just float around on the breeze. If wind can get in, so can bacteria. They can't climb, fly, walk, swim, teleport, or otherwise move themselves. They must be carried along on air currents. Tinfoil blocks that. Airlocks also block that. Tinfoil costs maybe .2 cents per use, while airlocks can last almost forever if used properly.

It's your beer, do what you like with it. I will tell you from experience though, tinfoil works just fine.
 
Wait until you get fruitflies floating in your beer turning it into vinegar. It's not precisely true that bacteria can't move. They can hitch rides on other things. And acetobacter just LOVE living on the bodies of fruit flies. And fruitflies love alcohol. In fact, they can metabolize alcohol fumes.

So yea, I will always use an airlock, especially during the warmer months.
 
Wait until you get fruitflies floating in your beer turning it into vinegar. It's not precisely true that bacteria can't move. They can hitch rides on other things. And acetobacter just LOVE living on the bodies of fruit flies. And fruitflies love alcohol. In fact, they can metabolize alcohol fumes.

So yea, I will always use an airlock, especially during the warmer months.

Yeah, I guess I should have mentioned fruit flies. Then again, I don't get them this far north, so I tend to forget about them.

Yes, if there are any curious critters (fruit flies, bugs, cats, dogs, etc...) they can bring bacteria into your fermenters. If you ferment in a closed area, and bugs aren't a concern, go for the tinfoil.


Edited: I wish I could metabloize alcohol fumes. :(
 
There is a layer of CO2 protecting your beer, but its not going to stay there without an airlock. If you only use foil, you're allowing the headspace to reach equilibrium with the surrounding atmosphere, meaning CO2 out, room air in. And oxidized beer.

An airlock is like 2 bucks. Why not use one?
 
There is a layer of CO2 protecting your beer, but its not going to stay there without an airlock. If you only use foil, you're allowing the headspace to reach equilibrium with the surrounding atmosphere, meaning CO2 out, room air in. And oxidized beer.

An airlock is like 2 bucks. Why not use one?

CO2 is heavier than air. It will just sit on top of the beer unless there are currents to move it. There are several people here who use foil and have no issues with it.
 
There is a layer of CO2 protecting your beer, but its not going to stay there without an airlock. If you only use foil, you're allowing the headspace to reach equilibrium with the surrounding atmosphere, meaning CO2 out, room air in. And oxidized beer.

An airlock is like 2 bucks. Why not use one?

Yeah, that's just incorrect. How exactly does O2 get in there, when CO2 is heavier? Perhaps the O2 just wants it more? CO2 is heavier than O2, which is why our beer has that lovely protective cushion.

I suppose my last ~20 batches of beer have all been oxidized? They've all been made using tinfoil in place of airlocks, so they must all taste like soggy cardboard. Crap, I guess I'd better dump this glass of Oatmeal Stout that I'm drinking! :drunk:
 
I regularly use, in order of frequency:

- tinfoil
- inverted half-pint jars
- a sheet of plexiglass (for bucket fermenters); get rid of those blasted lids.
- 3 piece airlocks
 
My airlock collection is collecting dust in my cabinet. I use alum foil or just a lid that is not absolutely airtight. I think airlocks are a nice idea for a beer or wine that will spend a long time in secondary. For a typical beer that's out and done in a fortnight, I think the risk is minimal to nonexistent. I don't see many fruit flys around here, but i'll admit, they make me nervous.

Now having the solution in the airlock go back into the fermenter...that really sucks...hah...badumbump.
 
Long secondaries... yeah, I'd call an airlock at least close to necessary. But outside of that and fruit fly season, a bit of sanitized foil works just great.
 
Ok...I'll go one further, sanitized tin foil?? I just assume fresh off the roll is pretty sanitary...no?

Pretty sanitary? Probably.

Worth risking 5 gallons of beer on? No way. Spray that sheet with some Star San, and set your mind at ease.

ChshreCat: You are exactly right. I'll do tinfoil for extended primaries (successfully up to and including 10 weeks) but I don't for secondaries. Maybe I'm just paranoid, and granted I don't secondary often, but for secondary I'll use an airlock. Good catch. :mug:
 
I see your point - beer doesn't spend enought time in the carboy for oxidation to be much of an issue. I did, however, lose a batch of wine to oxidization after I'd let the airlock dry out.

I know that CO2 is heavier than air, but I would argue that it doesn't take much to create enough of a disturbance to "splash" CO2 out of a carboy once fermentation has stopped - opening a nearby door, walking past, whatever. CO2 is heavy but it's not that heavy.

Like you said - I'm sure your beer turns out fine but after dumping that 6 gallons of wine I'm an airlock fan.
 
Well, you got it half right.

The point wasn't that months > weeks, altough kudos to you for catching that subtle one.

The point was that tinfoil works just fine for beer, which only needs a few weeks in the fermenter to reach it's ideal flavor. Wine, on the other hand, takes many months or even years. While tinfoil will work fine for Home Brewing Beer which is the title of this forum and the subject of the original post, it might not be ideal for other things. If you really need 100% clarity, tinfoil is also not ideal for the following subjects not covered in this forum: Spacecraft Propulsion, Automobile Oil Changes, Guitar String Replacement, Homemade Cat Food, Digital Camera Lens Repair, Shoe Cobbling, etc...

Do I really need to continue, or is my point noted?
 
I just drew a sample of my Tripel that's been sitting in a carboy for 5, almost 6 weeks under foil (which is aluminum, not tin ;)) and it is fine. No sherry/cardboard from oxidation. I'll bottle tomorrow and expect it to be just fine for months to come.

There's been plenty of fruit flies in my apt during summer months, and none have gotten to my beer. Again, to each his own.
 
All my jars are the right way up. Anyone know where I can get some inverted ones?

Yes, but I'd hate to part with one of my lovely hats.

I just drew a sample of my Tripel that's been sitting in a carboy for 5, almost 6 weeks under foil (which is aluminum, not tin ;)) and it is fine. No sherry/cardboard from oxidation. I'll bottle tomorrow and expect it to be just fine for months to come.

There's been plenty of fruit flies in my apt during summer months, and none have gotten to my beer. Again, to each his own.

I was hoping you'd chime in here! PseudoChef is the guy who first convinced me that tinfoil (or aluminum foil! :p) worked just as well as an airlock at keeping the bad bugs out. And just for you, tinfoil starter:

starter6.JPG
 
ANTS! ANTS! ANTS!

A while back, I had a rather aggressive blow-off pop the air-lock off and spew brown suds all over the carboy. A quick restoration and clean-up didn't stop the army of ants that 'had the scent' and roamed all over the carboy for the next week until ferment was over. The airlock kept them out; I doubt that a foil cap would have. And the high-gravity ale turned out superbly.
 
I don't really get this question. Certainly you can brew without many of the tools we use but with an airlock and bung/cap costing a couple bucks, why would you? :confused:

I buy airlocks and bungs for something like 79 cents each and they can be used for hundreds of batches of beer. We still use the same airlocks and bungs we bought 5 years ago when we started brewing. What would be the advantage to using foil?
 
I don't really get this question. Certainly you can brew without many of the tools we use but with an airlock and bung/cap costing a couple bucks, why would you? :confused:

I buy airlocks and bungs for something like 79 cents each and they can be used for hundreds of batches of beer. We still use the same airlocks and bungs we bought 5 years ago when we started brewing. What would be the advantage to using foil?

Less chance of blowoff or suckback, easier to remove and replace for taking samples. And probably less chance of infection since you're sanitizing a fresh (ie very clean) piece of foil for each batch.

The only advantage of the airlock + bung on a primary that I can see is that you can watch it bubble. That's enough for me to use them sometimes, but that's mostly aesthetic since I'm going to test for doneness with a hydrometer anyway.
 
Well I may be a newbie but I work in the medical industry and have to deal with sanitizing various products that go under patients. We aren't dealing with natural cork anymore, the new man made rubbers and plastic can be cleaned effectively.. I'd go with the .79 cent airlock.. I do use tinfoil on some yeast starters as I don't have a airlock that wll fit properly..
 
Less chance of blowoff or suckback, easier to remove and replace for taking samples. And probably less chance of infection since you're sanitizing a fresh (ie very clean) piece of foil for each batch.

The only advantage of the airlock + bung on a primary that I can see is that you can watch it bubble. That's enough for me to use them sometimes, but that's mostly aesthetic since I'm going to test for doneness with a hydrometer anyway.

Easier to remove? Is it hard to pull a stopper out?

I use airlocks for everything but starters. I don't see anything wrong with using aluminum foil, but I do have a major fruit fly issue, and I feel more comfortable with airlocks because of it.
 
I have always, and will always, use an airlock on primaries and secondaries. At $1-$2 for a little piece of plastic, I don't see the point in risking it. For those who say their beer never tastes oxidized when using foil, have you ever done a side-by-side control experiment? Brew a double batch, split into two fermenters, put foil on one and an airlock on the other. Keg/bottle them side-by-side and do some taste tests later. I've known several people who have had batches turn out way-less-than-optimal by letting their airlock dry out without knowing and getting a few days of oxygen exposure.

And yes, while CO2 is heavier than oxygen, small thermal fluctuations and/or wind disturbances are enough to disrupt that CO2 barrier layer enough to make it less effective, especially if you're only using foil. We're talking about two gases that yes, have different masses, but certainly mix to an extent in real conditions that exist in a carboy. That's why whenever I introduce oxygen into my carboy (gravity check, racking to secondary, etc.) I purge the headspace with CO2 from my keg line before returning the airlock. Easy steps to making sure your beer turns out the best it possibly can. Sure, you can take shortcuts like using foil and chances are your beer will probably turn out fine - but if you can spend one extra dollar and take a couple of extra precautions (that aren't difficult), why wouldn't you?
 
How to tell if your SWMBO is a sci-fi geek:

When I read the title of this thread to her (Is an airlock really necessary?), her response was, "Well, it's a really good way to kill someone on a spaceship."
 
Yeah, that's just incorrect. How exactly does O2 get in there, when CO2 is heavier? Perhaps the O2 just wants it more? CO2 is heavier than O2, which is why our beer has that lovely protective cushion.

I suppose my last ~20 batches of beer have all been oxidized? They've all been made using tinfoil in place of airlocks, so they must all taste like soggy cardboard. Crap, I guess I'd better dump this glass of Oatmeal Stout that I'm drinking! :drunk:

Well the reason the CO2 might stay is b/c it's still being produced, but it doesn't matter if it's heavier, the surrounding atmosphere will still diffuse. I remember in under grad physical chemistry lab, we did a similar experiment but with much heaving gas (Argon) and the diffusion hole was pin-sized. It does happen more than you might think.
 
I have used plastic wrap on all of my brews. I ferment in a plastic bucket and take a large rubber band and put it around the rim so it holds the plstic wrap on. Then I take a little piece of the plastic wrap out from under the rubber band so the CO2 can get out.

You might be asking why I do this? Well that's just how I learned. The guy at the LHBS where I bought my starter kit told me to do it that way and I have been doing it ever since.

However if I am going to bulk age I do put it in a glass carboy and use an airlock.
 
I am kind of a set and forget kind of guy and embarrassingly enough I have flat out forgot to put the air lock in or starsan in the airlock. I have come back 3 weeks later and not had a problem with the beer. Well other than one time a fruit fly decided to commit suicide and drink himself to death. I fished him out and tried to give him mouth to mouth but it was just to late for the little feller.

Beer turned out good though
 
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