Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
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Carlos Macku, Ph.D.,
Kyle Reed, Ph.D.,
Department of Technical Services,
Cork Supply, Benicia, CA
ntil the early 1980s, natural cork was basically the only material used by the wine industry to close a bottle of wine. Cork was the only choice because it was considered the perfect material, unchallenged by centuries of winemaking practice. Then in 1981 and 1982, Swiss scientist Hans Tanner and his team published research that made the landmark association between 2,4,6-trichloroanisole (TCA) and cork taint.1,2
Winemakers have always been well aware of cork taint, but the problem was considered a very minor annoyance due to its very low rate of incidence. However, anecdotal accounts
have reported that, since the end of World War II, the rate of taint climbed close to double-digit figures, particularly during the 1970s and 1980s.
This situation, understandably, created much angst among winemakers, while at the same time leading to an epic struggle to find a satisfactory means of wine packaging. During the ensuing years, innovative and entrepreneurial individuals worked hard to develop reliable and consistent wine closures that kept precious wine vintages away from oxygen with no negative effects.
At the same time, commercial globalization and the renaissance of scientific winemaking have added product convenience and quality consistency to the potential benefits of new and daring closure alternatives to natural cork.
Today, producers and consumers can choose from many types of wine closures. Wine packaging (probably one of the most challenging of all food barriers) has certainly evolved from the days when the product was transported, stored, and sold in Egyptian amphorae or medieval wooden barrels.3
For the last ten years, three types of wine closures have clearly dominated the market: natural corks, synthetics, and screw caps or screw tops (also known as Roll On Tamper Evident or ROTE). Other types of closures are also available, such as Vino-Seal, and Zork. Nevertheless, this article will focus on the first three types of closures and establish useful comparisons between the three systems.
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FIGURE 3: Oxygen Transmission Rates for the most widely-used wine closures (based on air measurements).