Rubber stopper

[castillo]

I have a 1000ml flask that takes a #9 stopper. But I can't seem to find a #9 stopper. I plan on making a yeast starter for my next brew in this flask. Any suggestions? Thanks.

 

[JewBrew]

Cover it loosely with a rubber band an plastic wrap or tin foil.You could always go with the old fashioned hole-in-a-balloon air lock.

 

[demonrichie]

take the flask wherever youd get a stopper and measure it right there. if it fits go for it

 

[Sacdan]

Don't use a stopper when making a starter. Use a piece of snitzed foil. You want Oxygen to get in and Co2 get out.

 

[wyzazz]

Loosely crimp a piece of sanitized tinfoil on that flask and you're all set!

 

[RiverCityBrewer]

I used a stopper one time for a starter, now its just foil as it is much easier to deal with when using a stir plate to allow for a good gas exchange.

 

[castillo]

I was planning on a using a stopper with an airlock. Does oxygen not get in with an airlock?

 

[wyzazz]

Nope, things get out not in with an airlock. Think of it as a check valve, it lets pressure out but not back in.

 

[k47k]

an 8 1/2 stopper fits a standard 1000ml flask.