I have read many times that you can use sanitized foil to make a seal or airlock for a a flask or mason jar in which you are harvesting yeast from a commercial brew.
I was just wondering how you want to arrange the foil? Do you want to get it as airtight as possible and assume that air will get out of it anyway?
I am just confused on how to actually use the foil
I tried to figure out how Revvy did his in http://www.homebrewtalk.com/f12/pacman-yeast-starter-video-63855/#post1617242 but couldnt quite figure it out
The point of the foil is to keep fruitflies and other critters out. You can just crimp it along the edges, so that it's closed.
Also, the foil doesn't create an air tight seal. You want oxygen in the bottle so the yeast can grow. Another reason to give it a swirl every once in a while; to encourage more oxygen in the starter wort.
Thanks a ton both of you!
That is exactly what I thought but I wasnt sure