Often times new winemakers reach for bleach when cleaning or sanitizing their wine equipment. Chlorine based bleaches are very effective at eliminating microbes and bacteria, but that is not the issue. Chlorine is one of the two key contributors to the creation of 2,4,6-trichloroanisole (TCA), which is a major wine fault. When a wine has TCA present beyond the sensory threshold, it is referred to as "corked" and will give off undesirable musty aromas. Even commercial wineries occasionally have problems with corked wines.
Beyond chlorine, the second major contributor to the creation of TCA is mold. Mold is commonly found in oak and cork products, even if they have been heavily sanitized. Minuscule bits of mold can become trapped deep within the pores of wood based products. The molds by themselves are really not a huge problem but once chlorine is added, it's game over. Cork and oak suppliers have been continuously improving their processes to attempt to eliminate trace amounts of mold and remove chlorine from the manufacturing process but TCA is still a common problem in the industry. If TCA is not present in the corks when they arrive, but you introduce chlorine, then you are playing a dangerous game.
What makes TCA such a pain in the buttocks is that the sensory threshold is unbelievably low. At less than five nanograms per liter, a taster will begin to perceive the unwanted aromas of TCA. That's less than five billionths of a gram! The smallest amount of TCA could effectively contaminate your entire cellar. A couple grams of the stuff in pure form, could contaminate all the wine in North America. Needless to say, professional winemakers take TCA pretty seriously...
As an alternative to chlorine bleach, consider using sodium percarbonate based cleaners like B-Brite for heavy cleaning and acid based sanitizers like Star San as a final step in the cleaning and sanitizing process.
If you have any great tips and tricks, please feel free to share in the comments thread below.
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