Ask Wine Wizard

Remove A White Film on Carboy


Steve Auer — Coos Bay, Oregon asks,

I have a large 12-gallon (45-L) carboy (see photo below). There’s a film on the inside of the glass. I’ve cleaned with One Step and have tried to scrub inside with a bottle brush many times. I Cannot remove film. The carboy currently has wine in it, but you can see its size. Any help would be appreciated.

Wow, looks like you’ve got a serious case of “Ring Around the Carboy.” Thanks for sending in the picture, I always love it when readers do that because, especially in cases like these, it gives me a good visual to go from. I can see that pesky stain on the inside of the neck of your carboy. One Step is a great cleaner but I’m not so sure it’s strong enough for your purposes here, i.e. it won’t really help you get that film off. If I were you, I’d make sure you had a stiff-bristled “carboy brush.” If your local homebrewing/fermentation supply store doesn’t have one, you can find one online by entering those terms into your search engine of choice. You want a brush with an angled handle and/or an angled brush, so you can get into every curve and corner of your fermentation vessels. Rather than use One Step again, I’d use something that’s a stronger base, which will help to break up the residue around the neck area. A classic that I love is peroxycarb, which
Response by Alison Crowe.