Changes

Ozone has been shown to be an effective way to kill ''Brettanomyces'' that is buried in the wood of oak barrels (it has been found to burrow as deeply as 8 mm into oak barrels), but the ozone must be applied for an adequate time to allow for the ozone to diffuse into the oak. The amount of time needed to completely kill ''Brettanomyces'' living within barrels with ozone is not known, but it was found that 30 minutes of exposure to 40 mg/m³ ozone concentration was not enough time. The concentration of ozone is known to be a more important killing factor than time <ref>[https://www.researchgate.net/profile/Raffaele_Guzzon/publication/225890726_Survey_of_the_yeast_population_inside_wine_barrels_and_the_effects_of_certain_techniques_in_preventing_microbiological_spoilage/links/5472f6170cf2d67fc035d45f.pdf </ref>.  The most effective and preferred method is to heat the inside of the oak barrel to at least 140°F (60°C) for 20 minutes with hot water or steam. This has been found to be an effective way of killing ''Brettanomyces'' within the wood of 3-year old barrels infected with ''Brettanomyces''. Note that this might not be hot enough to kill other heat tolerant microbes, however these heat tolerant species tend not to be beer spoilers. Treatments that are higher in temperature and longer should be fine with steam, however if hot water is used then the longer the water is exposed to the barrel the more character from the barrel that is gets soaked out <ref>[https://www.ncbi.nlm.nih.gov/pubmed/25989358 Heat inactivation of wine spoilage yeast Dekkera bruxellensis by hot water treatment. Fabrizio, Vigentini, Parisi,Picozzi, Compagno, Foschino. 2015.]</ref><ref name="Agnolucci_2017">[https://link.springer.com/article/10.1007/s11274-017-2345-z Brettanomyces bruxellensis yeasts: impact on wine and winemaking. Monica Agnolucci, Antonio Tirelli, Luca Cocolin, Annita Toffanin. 2017.]</ref>.