Yeast Starter Airlock

[dfohio]

Hey everyone, I have been researching yeast banks and yeast starters and have run into the following argument; Should one use foil loosely on the flask or should one use an airlock? Now, the majority say just to cover with foil to allow oxygen in which will promote more yeast.

My thought is this. Can't one use an EMPTY sterilized twin chamber airlock on the starter? Won't the dual chamber design act like a goose neck flask? Please give me your thoughts. Thanks.

 

[dfohio]

Sorry, could someone move this to the appropriate sub forum

 

[Fingers]

I use a standard airlock with liquid inside. You can oxygenate or aerate initially, but I wouldn't add any air while it's fermenting. Treat it just like a mini-beer.

 

[dfohio]

Isn't the point of using a stir plate is keep yeast suspended and consistently oxygenated? Here is a writeup concerning the issue on maltosefalcons.com

MB Raines, Ph.D. - Guide to Yeast Culturing for Homebrewers - Maltose Falcons Home Brewing Society (Los Angeles Homebrewing)

 

[caskconditioned]

I was actually just listening to the latest podcast on the brewing network. The "brothers White" are proponents of simply using tin foil for starters. They do mention a possible build-up of pressure using a standard air lock w/ liquid (potentially bad for the yeast)??

For ease, I usually use tin foil or a sponge stopper. I've had the rubber stopper w/ air lock pop off before (star san is slippery stuff) and it's just not worth the headache IMHO.

 

[dfohio]

Well that is why my comment was based on using a dual chambered airlock WITHOUT liquid and taking advantage of the gooseneck design. That is my question; Does a twin chambered airlock act as a gooseneck flask

 

[caskconditioned]

Well that is why my comment was based on using a dual chambered airlock WITHOUT liquid and taking advantage of the gooseneck design. That is my question; Does a twin chambered airlock act as a gooseneck flask

I don't see why it wouldn't work. My only concern would be that the twin chamber can become a resting place for some unwanted yeast/bacteria/nasties- and in the event you get negative pressure (say the temp drops and it sucks air in) or whatever causes it force air into the starter, you just exposed it to everything collecting in the twin chamber. Yeah, it will work, but are there safer ways of going about it? I believe there are.

Edit: I should clarify that I'm talking about post-fermentation (after the starter is finished). Obviously, during fermentation you are producing co2 so it's a non-issue. So if you are pitching mid to end of fermentation I don't think it would be as risky as I stated above.

 

[dfohio]

I understand what you are saying. But isn't tin foil just as susceptible to negative pressure and other unwanted phenomena? I would think a gooseneck would be even more sanitary.

 

[raceskier]

The foil and empty airlocks are both theoretically sterile.

In this experiment performed by Pasteur, the sterile broth remained uncontaminated after years with basically an S airlock:File:
Coldecygne.svg - Wikipedia, the free encyclopedia

But, these breathable stoppers: #10-11 FOAM STOPPER @ Williams Brewing are so inexpensive and so easy to use, why not pick a couple up?

 

[dfohio]

Pasteur used cotten balls which would be even cheaper. Though if the foam stoppers really do hold up to autoclaving then they would be perfect

 

[steelerguy]

I think you will be fine with either, but foil just seems easier to me, plus I would think there would be better gas exchange.

 

[fratermus]

Though if the foam stoppers really do hold up to autoclaving then they would be perfect

I have pressure cooked some at 15psi/15min, and foam stoppers didn't disintegrate. They never would re-expand out all the way the normal size again but they still sealed fine. I just use foil now and leave the foam in the drawer.

 

[caskconditioned]

I just soak them in star-san and then squeeze them hard before using to strain the liquid out. They work like a charm. I have not tried pressure cooking them.