Foam Stopper 46-50mm

These stoppers are great for using with Yeast Starters or when washing yeast using a 2000 ML flask. Drilled stoppers and airlocks are not necessary for starters and these foam stoppers are easier to sanitize and fit than aluminum foil.

I just went ahead and bought a handful of these to use for future yeast starters. Not sure if they "go bad" or not but at some point I just feel more comfortable replacing them once they start to look a little shabby. Seems safer than aluminum foil and allows for adequate transfer of gases.

Works better than an airlock on starters-can be inserted as soon as you finish boiling. Also fits in the mouth of my 5 gallon carboys, to keep them sanitary in storage.

I use these on my yeast starters. For yeast starters you want a free exchange of carbon dioxide and oxygen. This allows more O2 into the flask and lets CO2 escape. The foam will keep dust from settling into your starter.

Work great for yeast starters using my 2000 mL flask. Will be purchasing more for my other flask and carboy. Good for putting on flasks and carboys when storing to keep from collecting dirt and dust inside.

I read the Yeast book and it says that when making a starter you want to oxygenate the wort, so the yeast can grow. So I use this foam stopper instead of an air lock. I rinse it in StarSan before using, and haven't had any problems.

I use this rather than foil or an air lock when making a yeast starter in a 2000ML Erlenmeyer flask so Oxygen can reach the yeast while it's growing. I rinse it out when done, an soak it in Star San before using it.

When I make a yeast starter I seal the end of the flask with this foam stopper (that I sanitized ahead of time. It keeps out dust, that can carry microbes and wild yeast, but allows CO2 and O2 to freely flow. Yeast in starters want O2 and should be constantly Oxygenated.