What can I use to cap off my conical Flask

[Snood]

I just got my first 2L conical flask in the post yesterday. the thing is much bigger than I had expected! I was counting on using a bored rubber bung which I already use with my fermenter barrel but the neck of the flask is far too wide for it (the opening is 45mm in diameter) I have found a larger bung on ebay but it wont arrive from the USE to Sweden in time for making a starter next week.

Does anyone have any ideas of what i can use to close the top of the flask off whilst still allowing either the use of an air lock or some alternative air locking solution?

 

[Horace]

For my starters I use aluminum foil without a problem. The foil is long enough that it goes maybe an inch or two down the sides. No need for an airlock.

 

[Snood]

wouly you ferment your brew with tin foil as your seal? if we go to such great lengths to ensure everything is correctly sanitised, surely the same care should be taken with starters?

I popped into the only homebrew shop in my city and was supprised to find something which will do the job quite nicely I hope.

Thanks for the input.

 

[OneHoppyGuy]

+1 on foil... I (my SWMBO) sprays the foil with Star-San first.

And yes, I am spoiled to have someone maintain the yeast for me... :rockin:

 

[Lennie]

Foil is certainly sanitary from the method of production, although if you heat your wort in the flask the heat will santize it as well as the flask.

 

[SenorPepe]

wouly you ferment your brew with tin foil as your seal? if we go to such great lengths to ensure everything is correctly sanitised, surely the same care should be taken with starters?

I popped into the only homebrew shop in my city and was supprised to find something which will do the job quite nicely I hope.

Thanks for the input.

I would not ideally ferment my brew with tin foil as my seal (EDIT: Actually I have and do when necessary). Then again I would not purposely oxidize it with a stir bar. Starters are not beers. You want oxygen to be able to get in as I understand it.

 

[GilaMinumBeer]

wouly you ferment your brew with tin foil as your seal?

In a carboy, yes. Yes I would.

 

[daksin]

Foil is the preferred method- an airlock isn't going to allow for maximum gas exchange/aeration of the starter which is the whole point of using a stir plate. Airlocks only let gas out, so once all the O2 is out of your flask, you're no longer adding oxygen back to the starter.

 

[Snood]

but if oxygen can get in, then surely other potential nasties can get in. I should guess the seal of tin foil is still adequite enough to not allow any significant amounts of oxygen in but not adequite enough for maintaining a sterile environment.

I get that the point of using the stir bar is to aerate, but isn't it also, and primarily to keep the yeast in suspension to promote full fermentation and therefore maximum yeast development?

 

[A4J]

not adequite enough for maintaining a sterile environment.

we try to maintain a sanitary environment, not a sterile one.

+1 on tin foil.