A two-day kosher wine fair opened in Jerusalem on Wednesday, and the question on many visitors' lips was: What exactly makes wine kosher? The wine fair at the Jerusalem International Convention Center (Binyenei Ha'uma) held in a cooperation with Wine and Gourmet magazine provides the perfect opportunity to answer that question. "Kosher wine starts in the vineyard with the orlah, which means that it is forbidden to use the grapevines from the first three years of the planting, but only from the fourth year," said Aryeh Ganz, the main kashrut supervisor for Carmel, Israel's largest winery. While his may seem to pose a serious economic problem, that is not necessarily the case. "Most vintners in Israel have contracts with wineries so they don't lose money if they spend the first three years strengthening the vines," said Ganz. "In addition, the grapes start growing only from the third year, when the crops are small and modest anyway, so the loss is not that big." Most Israeli vineyards strictly observe the Jewish law of shmita - the final year in a seven-year cycle during which land in Israel must lie fallow and debts are canceled. Today there are creative ways to get around this law, Ganz said. "One of them is by symbolically selling the land to a non-Jew for the shmita year and buying back the crops at a low price while sharing the seventh year's profits," he said. Unlike in other countries, where dead or weak grapevines are replaced every year with new plants, Israeli vinters cannot do this because of the shmita and orlah laws. "We have to keep track of the vineyards we work with to make sure no changes that can damage the wine's kashrut have been done," Ganz said. As a supervisor who has to keep up with 15,000 dunams (3,750 acres) of vines, Ganz uses a computer program that was developed for this exact purpose and uses the Global Positioning System to assist him in supervising each vine. Jewish law also bans letting the wine be touched, and sometimes even seen, by a non-Jew or even by a non-observant Jew, from the moment of pressing the grapes to the bottling. To make sure this law is observed, kosher wineries employ only haredim. This law also forces the wineries to have every visitor accompanied by a kashrut supervisor, to make sure nothing is touched. "It can be embarrassing sometimes, but there is no other choice since you cannot be sure how religious a person is and you certainly cannot ask him," said Tvzika Shor, the vintner at Zion Wineries in Mishor Adumim near Jerusalem, which produces glatt kosher table-wine under the supervision of the Badatz Eda Haredit. Likewise, all substances used in the process, such as yeast, sulfate, sulfur dioxide or tartar, most of which are made in European factories and supervised by the relevant kashrut institutions, have to be kosher. Wineries like Carmel that produce the substances themselves can reduce their costs. There is a popular rumor that all kosher wine has to be boiled and therefore does not taste as good as non-kosher wine. "Many kosher wineries do not boil wine that is not for export," said Ganz. Jewish law stipulates that kosher wine can become non-kosher Nesech wine if it is opened and poured into glasses by a non-Jew or a non-observant-Jew, unless it has been previously boiled, he said. Nesech wine was used by pagans in religious rituals and was forbidden to Jews in the days of the Sanhedrin. Shor added that boiled wine means wine that was cooked for 22 seconds at 87 degrees Celsius. "The Israeli wineries target their kosher exported wine toward religious customers abroad. They assume that the observant Jewish customer will prefer to order the boiled kosher wine on the menu rather than embarrassing the bartender or waiter by not drinking or, even worse, asking them to let them open and pour the wine themselves," said Ganz.