Airlock or foil on a yeast starter?

[Bduce77]

The starter kit I purchased comes with an airlock, but I see everyone using foil to cover the glass while it’s on the stir plate. Is it ok either way?

 

[day_trippr]

You do want to allow O2 ingress - that's pretty much the whole reason for using a stir plate.
While physics would allow for O2 to make its way through any "air lock", I think it's sub-optimal and given the choices would go with the foil.
For the record, I use open cell foam plugs on my e-flasks...

Cheers!

 

[eltorrente]

Fruit flies can get by foil. I use foam airlocks on my starters, and they work great.

 

[pinchegil]

Fruit flies can get by foil. I use foam airlocks on my starters, and they work great.

+1 . here is an interesting article on this http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/

 

[myndflyte]

I just use saran wrap. Blocks fruit flies but allows air movement.