Foam Stopper 46-50mm
Breathable foam stoppers will withstand boiling or autoclaving temperatures, making them ideal for use in preparing a yeast starter. The honeycomb structure of the foam stoppers will act is a filter for any airborne bacteria or wild yeast that might enter the flask. That important because a lot of air is sucked into the flask while it is cooling. You can also leave the stoppers on the flask instead of a fermentation lock. Some people use foam stoppers to replace fermentation locks in their carboys, too.
The large foam stoppers are 46-50 mm wide and fit our 2000 ml borosilicate glass flasks.
This came in handy when I had to use a 2000 ml beaker to start my yeast for an Imperial Red Ale. Easy to use and easy to clean.
I use it for my yeast starter flask. When swirling the starter try not to let it touch the stopper because that stain doesn't come out.
Fits my 2L flask i use for yeast starters perfectly. Makes a nice, tight fit that keeps dust out and lets the starter breath. as with any foam, these have about a 9 month lifetime for me, but i can soak up sanitizer, squeeze it out and let it work.
it is a foam stopper. What else to say. I use it in my yeast starter flask.
Only used it once so far. After use I washed it with warm water and it kept its original shape!