Ask Wine Wizard

What is the best way to store plastic fermentation tubs and keep them clean?

TroubleShooting

Ray Ruthenberg — Woodbine, Illinois asks,
Q

Many home winemakers have food grade plastic tubs (5 or 6-gallon volume) used for primary fermentation, stored for that fantastic next batch. I formerly used bleach to keep them clean, until I read about the bleach/corkiness connection. So, then I switched to sodium sulfite for the tubs. I’ve always kept an inch or so of relatively fresh sulfite solution in the covered tubs, to keep them sanitized (sometimes for months). Is this the best method, or would it be better to clean the tubs out, dry them and keep them covered to exclude airborne beasties?

A
You’re on the right track — it’s not a good idea to mix chlorine bleach with winemaking because free chlorine molecules can, if the conditions are right, contribute to appreciable levels of the swampy or stinky “corked” aroma, the most ubiquitous being 2,4,6-trichloroanisole. I never use any chlorine-containing cleaning compounds in my winemaking and don’t recommend it to anyone. There are plenty of alternatives for cleaning, one of my favorites being sodium percarbonate. It also sanitizes (depletes microbial cell count) on clean surfaces as it contains 13% available oxygen and is a strong oxidizer. You’re also on the right track by thinking it might be better to clean your fermenting tubs thoroughly and then dry them out to store them for next time. In my experience in the cellar, even closely-monitored “wet storage” solutions lose their potency with time. Forget to add more sodium metabisulfite powder to your storage solution, go on vacation for two weeks and you’ll probably come back to a microbial house party in your tub — hosted by those same “airborne beasties” you were trying to
Response by Alison Crowe.