Ozone with its strong sterilizing ability makes it very useful in many aspects of wine processing. Ozone can be used in everything from clean-in-place systems to control bacteria in barrels by sanitizing it. Often ozone can offer a safer, less costly and effective solution than traditional chemicals. Ozone fights against bacteria such as pseudomonas, flavor bacterium, streptococcus, legionella, etc. Ozone is especially effective against fungi and bacteria, which are the main cause of degradation of vines. Ozone is very efficient against these microorganisms.
It's important to understand that barrel sanitation using ozone is not the same as barrel sterilization. The surface of barrels do not have a discrete surface, it is more like a 4-5mm sponge, often with blisters. The porosity of the barrels provides far too many nooks and crannies for ozone in any concentration and duration to completely eradicate all microbes. The ozone treatment of barrels is designed not to eliminate microbes, but instead to control them. This concept of microbial control is especially important when ozone is used to treat barrels with high populations of microbes, which can produce off-flavors or cause wine spoilage.
Many wineries have implemented ozone as a part of their barrel-washing practices. Standard procedure for barrel washing varies from winery to winery, but it typically includes a high pressure, hot water rinse, followed by a dissolved ozone water treatment.
The concentration of ozone applied, as well as the contact reaction time in the barrels, depends on the quantity and nature of the contaminant. Larger quantities of microbes in contaminated barrels require longer treatments, but smaller doses may be required to handle sensitive materials.
Typically, a 2.5 ppm ozone concentration for two-minutes on healthy barrels, after a hot water flush, is sufficient. If the barrel is severely contaminated, a five-minute treatment may be required.
Ozone washing of barrels saves money and reduces high costs of replacing with contaminated wine barrels.
As ozone is the non-chlorinated cleaner for initial sanitation, years of experience has proven that it should also be used for additional follow-on rinses as well. S.S tanks may keep empty for week or more after initial sanitization. Many wineries rinse all the s.s vessels with ozonated water immediately prior to filling to ensure proper sanitization.
A broad range of surface and equipment are routinely sanitized with ozonated water to control unwanted microbes and contamination. Bottles and bottle equipment are sanitized with ozonated water as well. Conveyors, floors, crushing machines, destemming machines are used routinely and effectively sanitized using ozonated water.
The biggest threat to winemaking is contamination during the long production process from harvest to tank to barrel to final bottling. Clean-in-Place (CIP) involves cleaning and sanitizing pump systems, pipes, tanks, hoses, filters and bottling lines. Using ozone in the CIP process saves time as well as costs. Dissolved ozone water is circulated through the piping systems and reacts with organic materials.
Many modern ozone generators have controls built-in which receive signals from ozone sensors connected to the pipes or tanks. This allows machinery to be cleaned and sanitized easily and automatically.
Without ozone, CIP sanitation must be done by one of these two ways. The first is by using chemicals, typically chlorine or iodine solutions, requiring multiple rinses afterwards to remove noxious residues. The other option is by using heat, usually high temperature water or steam, which is very expensive to produce and creates a danger for cellar employees. In contrast, ozone achieves CIP sanitation at low cost, at ambient cellar temperatures and without harsh chemical residues. Furthermore, hot water or steam causes the expansion and contraction of welds, one of the biggest causes of line degradation and repair. Heat can also bake on materials inside the lines, making them more difficult to clean. Since ozone is used in cold water, it avoids these and other issues caused by heat based CIP sanitation.