Stop Putting Airlocks on Your Starters!

[flyangler18]

Duh, could just put the bucket in a larger bin to catch everything.

Bingo. We have a winner.

 

[Baja_Brewer]

Very informative. PROST!

 

[TrojanMan]

This is an excellent thread. :rockin:


I was planning to put together a starter this evening and I have newfound inspiration. It's just for a low-gravity pale ale (gotta have something to session, right?) but I'm excited to see how this works out.

I am absolutely fired up now.

 

[remilard]

Would one of these in a stopper serve the same purpose, but relieve any stress about contamination?

I don't think there should be any concern about contamination. Bacteria and yeast travel through the air on dust particles. Unless you have strong drafts, foil is fine. If you are really concerned, the foam plugs are cheaper and can be autoclaved. My problem with these filters is, how do you keep the filter itself sanitary? I would get the foam plugs and boil them between uses or autoclave (pressure cook) if convenient.

 

[Homercidal]

I can't see too much air exchange going on once the CO2 blanket gets formed. I'm guessing that once that happens there is a whole lot of CO2 above the starter, and not much else.

But I do agree that there is no need for airlock and that foil would be easier and just as safe for contamination (unless you feel the need to pull that foil off every other hour for whatever reason...)

 

[springer]

I can't see too much air exchange going on once the CO2 blanket gets formed. I'm guessing that once that happens there is a whole lot of CO2 above the starter, and not much else.

But I do agree that there is no need for airlock and that foil would be easier and just as safe for contamination (unless you feel the need to pull that foil off every other hour for whatever reason...)

I may not be an expert on starters but I would tend to agree with Homercidal. CO2 is heavier than O2 it will stay in the flask. I don't think the stir plate will mix the O2 into the CO2 all that well. I think my next starter I will hit the starter every few hours with the O2 tank and stone see if there is a difference

 

[flyangler18]

I may not be an expert on starters but I would tend to agree with Homercidal. CO2 is heavier than O2 it will stay in the flask. I don't think the stir plate will mix the O2 into the CO2 all that well. I think my next starter I will hit the starter every few hours with the O2 tank and stone see if there is a difference

By keeping the yeast on the stirplate, you're delaying fermentation. When the yeast switch from an aerobic to anaerobic phase, then fermentation starts.

 

[conpewter]

I know a stirplate mixes the air and Co2 very well, just put some water in, get a 1L vortex and blow some smoke in the flask.

 

[Beerbeque]

I use big plastic soda bottles for starters. That way I can easily squeeze some CO2 out, release it and it breathes fresh air in to aid yest growth. I just leave the cap on loose.

 

[BioBeing]

Would one of these in a stopper serve the same purpose, but relieve any stress about contamination?

Those puppies (the ones I use in the lab anyway) are designed for a one way air flow. They are not going to get the exchange being talked about here (air in, CO2 out). Plus, if they get wet, they clog, then your system is pressurized.

As a working scientist who grows bacteria that need lots of air (oxygen), +1 on just using foil. It really is what we do. Foam bungs work well too. Continuous shaking/stirring (especially in a baffled flask) is required for good gas exchange.

Saran wrap is not so good, as it is not very permeable to gases (but you can get something like saran wrap that is designed to be permeable, for just this purpose).

 

[AnOldUR]

Those puppies (the ones I use in the lab anyway) are designed for a one way air flow.

Not that the rest of your points are not correct, but not so sure about this. It's not like there's a check valve built in. As far as I know, the only reason that they have a direction arrow is so that you don't flip it in subsequent uses and put the contaminated side in. Anyone know for sure?

 

[BioBeing]

I think there is a prefilter on one side, but not the other. I might be wrong. But you are correct that they are not like an airlock (truly one way).

 

[Rhymenoceros]

So air locks can build some pressure, but what about blow off tubes? I s'pose I could put foil over the 2nd tube on the carboy cap though. Im convinced though, on my 6 gallon carboy I will now use foil instead. As for a starter, if I don't have a stir plate, should I just shake it, or do that soda bottle method?

 

[llazy_llama]

PseudoChef has been trying to sell us on tinfoil for a while.

Well, +1 for foil. Consider me signed up after I just shoved a stupid rubber stopper so far into my carboy I don't know how the heck I'm getting it out. I'm sold on tinfoil.

 

[flyangler18]

PseudoChef has been trying to sell us on tinfoil for a while.

It bears repeating now and then, especially with starters. Slapping an airlock on a starter is counterproductive.

 

[blindtiger]

I've never really considered the foil method until now. Consider me sold, especially since Ive been having trouble with my oxygenation.

 

[PseudoChef]

Yeah, I can be a crass jerk sometimes, but everyone's had that moment where you're staring at the airlock, or the grommet falls in, or there's suckback, or you're counting bubbles to measure fermentation, etc. As Charlie P. has reiterated ad naseum, I'm just wanting people to relax more and not worry.

The other thing is that Chris White has a big role in lots of people's beer. He does this stuff day in/day out to bring people the best yeast possible. If they're testing their flavor profiles and publishing their yeast statistics on fermentations done with lower pressure, then that's what I want to do to have similar results.

 

[OLB]

PseudoChef has been trying to sell us on tinfoil for a while.

Well, +1 for foil. Consider me signed up after I just shoved a stupid rubber stopper so far into my carboy I don't know how the heck I'm getting it out. I'm sold on tinfoil.

Check out this thread to get your rubber stopper, it worked for me.

 

[SpanishCastleAle]

Weird that just last night I made a second starter for a double-brew weekend and since I don't usually make two starters at once I had to improvise and used foil on the second one...first time ever that I didn't use an airlock on a starter.

Help with this apparent paradox though:
It has been mentioned that unless you are using a stir plate that there isn't much exchange of air/CO2. And if there is no exchange of air/CO2 then this doesn't really do anything for us.
But if there is an exchange of air/CO2 then there MUST be chance of infection shouldn't there? The ole 'you can't have it both ways'. Lotsa stuff is just 'airborne' whether it's bacteria/spores/etc. If you are pulling in unfiltered, untreated air then it seems you are pulling in contaminants (bacteria don't need to 'crawl' in...they float in like a hot air balloon, hitch a ride on a dust particle, etc.). I have a dog and I'm sure he stirs up some dirty, dog-hair contaminated air.

What they do in a lab and what we do in our homes are very, very different things. For one thing, most labs use 100% make-up air (i.e. 0% recirculated) whereas most homes are 0% make-up. Most labs don't have pets or kids running around. Etc. So imo regarding the 'they use foil in labs' arguement...that hat don't hold water imo.

EDIT: Maybe it's because we have Cleanrooms where I work and we have airborne particulate monitors and I've seen the monitors go berserk from all the dust/dirt in the air that we can't see. When we test a small room for particulate...you can't go in there and walk around...it would fail everytime because of all the dust you are stirring up (and it's not close...just watch the readout on the monitor when a person walks by...spike).

 

[springer]

By keeping the yeast on the stirplate, you're delaying fermentation. When the yeast switch from an aerobic to anaerobic phase, then fermentation starts.

I didn't know that by keeping it in motion it wouldn't switch to anaerobic.

I know a stirplate mixes the air and Co2 very well, just put some water in, get a 1L vortex and blow some smoke in the flask.

Not to be wiseass but wouldn't blowing smoke into the flask mix the air? Is it that the smoke now show's its swirling like the liquid? But What I am saying is without some other force the CO2 will sit on top and spin but not mix with the outside air .

In my house with force hot air, wood stove and 2 dogs I think the likely hood of contamination would be very high without something on top. I just use growlers and place the cap on it without twisting it on.

 

[nealf]

Well, +1 for foil. Consider me signed up after I just shoved a stupid rubber stopper so far into my carboy I don't know how the heck I'm getting it out. I'm sold on tinfoil.

I've used aluminum foil for about a month now... I'll never go back!!!

 

[Tonedef131]

I didn't know that by keeping it in motion it wouldn't switch to anaerobic.

It's not keeping them in motion that does it, it's the constant exposure to oxygen. When yeast have oxygen available they use that and the maltose to create water, CO2, and more yeast cells...obviously this is the reproductive stage. But once the oxygen is used up (or they have created enough cells) they will switch to creating alcohol and CO2. Keeping them in motion just allows them to have easy access to the sugars and nutrients they need to work.

 

[flyangler18]

I didn't know that by keeping it in motion it wouldn't switch to anaerobic

It's not simply keep them in suspension that does it, it's the presence of oxygen. If you are continuously agitating, as on a stirplate, with a separation medium that allows for gaseous transfer, the yeast are in a reproductive phase. Once oxygen is no longer absent (and this is me trying to synthesize what I've been reading), the yeast switch to an anaerobic phase, consuming the sugars present in the wort. If you don't have fermentation, then you're not getting a CO2 blanket.

Of course, there is a practical limit. 36 hours on the stirplate and it's done.

 

[PseudoChef]

Here's a link that has been mentioned before, but is worth repeating: MB Raines, Ph.D. - Guide to Yeast Culturing for Homebrewers - Maltose Falcons Home Brewing Society (Los Angeles Homebrewing)

 

[Medo]

Ahoy hoy,
Interesting thread indeed. I like the concept but would try a different implementation. If I were to try this, I would still use an airlock, but, would leave it empty. The airlocks I have are the type that you can remove the cover, and lift the floaty cap off of the tube going into the cork. And the cover is vented. Ive noticed the floaty, due to its rounded top, will not plug the tube when it is sitting all the way down on it, like you would have with no liquid in it. Surely this would allow unrestricted breathing of the primary. And I would think it would be even more complicated for a bug that cant figure out how to circumvent tin foil, to works it way through an empty airlock.
Besides, think of all the aluminum trees that would be saved if we used less foil
Just a thought....
I bid you all a great day!

 

[delboy]

Just like to add that i've been using the tin foil method since i started but then again i work with bugs etc and i understood the purpose of a starter and gas exchange and the effectiveness of a simple cover on a flask.
Mentioned it a couple of times on a couple of threads but it never seemed to register.
Anyway i digress, +1 on the fact that labs use foil on flasks and they don't get infections and nether will you

 

[dontman]

I've always used a starsan moistened paper towel as my "airlock" on my starters.

The primers I have read on starters all mention not to use an airlock so I never considered using one.

For my bigger starters I use a 96 oz apple juice pitcher and encourage air exchange by squeezing and releasing it several times prior to shaking it.

 

[BierMuncher]

Just in time for my 1.075 dubbel I'm doing tonight.

But I'm still going to rig a blowoff on the 6.5 carboy. But maybe I'll drape the hose into an empty bucket.

 

[user 22118]

I got tired of not knowing my fermentation temperature so I started doing this. Put the thermo into the hole in the bung and it rests easily and lets gas escape.

The pics below show before, from side and from top. I just pitched this IPA at 1.075 in the pics.

 

[dontman]

My probe would have to be a foot long to reach that far enough into the wort to be accurate. Mine would only reach the krausen at best.

I wish I had a longer probe.