Ask Wine Wizard

I’ve heard that a lot of wineries are using ozone for their sanitation programs…


Bernice Michel — Fillmore, California asks,

I’ve heard that a lot of wineries are using ozone for their sanitation programs. I make about ten barrels of wine a year — should I buy an ozonator machine?


Wine Wizard replies: Though ozone is an excellent tool for winery sanitation, the short answer is that unless you’ve got over fifty barrels of wine and sell it for a living, you probably are better off leaving the expensive machines to those that can justify the expense. The machines that generate ozonated water run in the thousands of dollars and at the scale you make wine the extra sanitation benefit you would get probably isn’t worth it.

Ozone is an unstable molecule that is a powerful oxidizer. Ozone-generators use UV light to zap air or piped-in oxygen gas (02) into ozone (O3). In most wineries, the ozone gas is then dissolved into a stream of water, which exits the stream as ozonated water and can be used to rinse tanks, barrels, drains, etc. Because oxygen really only likes to exist either in its natural gaseous form (O2) or connected to molecules that are easy for it to turn into, like water (H2O), the third, unstable oxygen atom in ozone is always avidly looking for somewhere else to go. This makes it an ideal candidate for sending a spare oxygen molecule over to say, a bacteria’s cell wall, disrupting that bacteria’s operations and, with enough of these rogue oxygen molecules (via adding across double bonds or decomposing to cause a free radical), killing it all together.

It’s easy to see why ozonated water (the easiest method of applying ozone to where you want it) has quickly become a sanitizing solution of choice for many wineries. It also “biodegrades” by quickly turning back into water or oxygen (if it doesn’t attach to organic matter like microbes) and if ventilated properly is harmless to humans (high concentrations of ozone in the air can be a respiratory hazard). However, with so many great sanitizers available to the small-scale winemaker, you’d really have to justify the cost before investing in an ozone generator for your winery. You can try mimicking ozone’s oxidizing power by using a hydrogen-peroxide producing powder, sometimes sold in the laundry section of supermarkets or increasingly through winemaking supply retailers. When dissolved in water, these powders form a strong base so you’ll have to make sure you do a citric acid wash and then clean water rinse after applying.

Update: Household ozone machines are now available at a more affordable cost.

Photo by Michael Larkin
Response by Alison Crowe.