Foam stopper for starter

As anyone out there ever used those foam stoppers NB sells for your erlenmyer flask ? I guess the principle is it will allow oxygen but not bacteria while allowing the starter to gas off as well. How are these things sanitized ? Etc. thanks.

You leave it in the mouth of the flask while boiling the starter wort and the steam sanitizes it.

Meh. Foil is easier.

If you aren't boiling in the flask you can soak the stopper in StarSan and squeeze it out. Enough stays in the stopper to sanitize it after you have touched it.

944play said:

you leave it in the mouth of the flask while boiling the starter wort and the steam sanitizes it.

Meh. Foil is easier.

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+1

i use them sometimes in a microbiology lab, we autoclave them. foil is easier and does the job

I use them all the time. Soak in starsan squeeze out and use.

i had a fruitfly get under the foil once, i've since switched to a sanitized paper coffee filter and rubber band and been very happy with that

Couldn't you just put a rubber band on the foil?

944play said:

You leave it in the mouth of the flask while boiling the starter wort and the steam sanitizes it.

Meh. Foil is easier.

Click to expand...

Wouldn't boiling it in the flask with the starter cause it to get sticky from eveporation ? I know in theory the water only boils off but in reality I know it gets sticky. Are these foam stoppers a one trick pony than dispose ?

jtejedor said:

Couldn't you just put a rubber band on the foil?

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you need to allow air in for yeast growth

Aschecte said:

Wouldn't boiling it in the flask with the starter cause it to get sticky from eveporation ? I know in theory the water only boils off but in reality I know it gets sticky. Are these foam stoppers a one trick pony than dispose ?

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They are not disposable, but they don't last forever either.
They don't seem to get sticky from the evaporation.
I like them much better than foil, especially when I'm chilling my wort as I can slip my probe thermometer between the glass and the foam and it is held firmly in place during the chill while keeping out any airborne bacteria.
They will also keep out any hungry insects during the ferment.
And they are super cheap.

OvaTersley said:

They are not disposable, but they don't last forever either.
They don't seem to get sticky from the evaporation.
I like them much better than foil, especially when I'm chilling my wort as I can slip my probe thermometer between the glass and the foam and it is held firmly in place during the chill while keeping out any airborne bacteria.
They will also keep out any hungry insects during the ferment.
And they are super cheap.

Click to expand...

+1 to all of this. I've done both the foam stopper and the foil and I generally prefer the foam, EXCEPT when I get blowoff. The foil tends to stay more or less on top of the flask, while the foam stopper just gets pushed out and then when the blowoff stops the flask is left uncovered. The smart solution is to not try to make a 2000mL starter in a 2000mL flask. At least not all at once. But if you're not a bonehead the foam stopper works great.

i use blowoff tube but the end is in the jar without water/starsan, so air can still get in, mess goes to the jar and everyone is happy (me, wife and yeast