easily spreads by using unsanitized equipment in wineries. Once the organism is present, it is difficult to eradicate. However, Brettanomyces is highly sensitive to sulfur dioxide (SO2); therefore, this is an effective antimicrobial pesticide for suppressing this organism.
Several bacteria species, including Lactobacillis and Pediococcus are contaminants that interfere with the wine making process. These organisms contribute to the pro- duction of excessive acetic acid, wine spoilage, and slowing the fermentation process (known as “stuck fermentation”).
Wine barrels represent a sizeable investment for wine producers, making it crucial to reuse these barrels and extend their usefulness through proper sanitization methods. Although using sulfur dioxide gas to fumigate barrels is the accepted stan- dard in the industry, winemakers and researchers have experimented with various other methods, including:
steam cleaning the inner surfaces
cleaning with ozone-saturated water
saturating the interior of the barrel with ozone gas
using dry ice particles to blast the inner surfaces
filling barrels with hot water
burning sulfur wicks inside barrels
FUMIGATING WINE BARRELS WITH SULFUR DIOXIDE GAS
The compressed sulfur dioxide gas you use for sanitizing wooden wine barrels must have a registered pesticide label attached to the gas cylinder. Sanitizing wine barrels must be one of the authorized uses listed on this product label. Never use a compressed sulfur dioxide product that does not contain a label for this intended use.
Prewash Barrels. Wineries use various meth- ods for washing out barrels that previously contained wine. This may involve high-pressure water, the use of soap or other solvents, or other effective methods preferred by winery management. Once you have washed the barrels, thoroughly drain and air-dry them according to the winery’s procedures.
Read the Pesticide Label. Before beginning to fumigate wine barrels, read the sulfur dioxide label, application information included on the label, and company operating procedures pertaining to this process. Make sure you understand all the hazards associated with using sulfur dioxide gas. Learn how to avoid these hazards. Be sure you have the proper PPE required by the label.
Check to make sure that any cylinder you are using to fumigate wine barrels or corks contains sulfur dioxide in the gas form and not the liquid form. Cylinders containing liquid SO2 are under much higher pressure than those containing the gas phase only. Using SO2 under high pressure will overdose the barrel and release too much SO2, creating a serious respiratory hazard. Liquid-containing cylinders employ an eduction tube to draw the liquid from the bottom of the cylinder, while the gas-containing cylinders must not have this device.