Is an airlock really necessary?

[PseudoChef]

I do use tinfoil on some yeast starters as I don't have a airlock that wll fit properly..

Don't use an airlock on your starter: https://www.homebrewtalk.com/f14/stop-putting-airlocks-your-starters-104529/

(And sig from Jamil Z)

 

[carnevoodoo]

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.

 

[Stef1966]

This is what i use:

https://www.homebrewtalk.com/f39/primary-bucket-quebec-style-100428/

I know... im a freak... but so far and never had any off flavors or infections doing this.
Of course the bag has to be a new one straight from the box.

As for starters, i use saran wrap over a plastic jug of some sort (previous peanut butter plastic jug).

 

[moti_mo]

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?

 

[jpsloan]

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."

 

[mkade]

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!

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.

 

[MgMt_Home_Brew]

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.

 

[Dr. Francois]

That is an exact depiction of my regular hat rotation.

Love this!

 

[Varmintman]

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