The Judaic dietary law, Kashrut, forbade lard as a cooking medium, and butter, too, was proscribed as an alternative since Kashrut also prohibited mixing meat and dairy products. Jewish cuisine used olive oil in the Mediterranean, and sesame oil in Babylonia, but neither cooking medium was readily available in Western and Central Europe, so poultry fat (known in Yiddish as "schmaltz"), which could be abundantly produced by overfeeding geese, was substituted in their stead. The delicate taste of the goose's liver was soon appreciated; Hans Wilhelm Kirchhof of Kassel wrote in 1562 that the Jews raise fat geese and particularly love their livers. Some Rabbis were concerned that eating forcibly overfed geese violated Jewish food restrictions. Some rabbis contended that it is not a forbidden food (treyf) as none of its limbs are damaged and the geese did not feel any pain in their throats from the process. This matter remained a debated topic in Jewish dietary law until the Jewish taste for goose liver declined in the 19th century. Another kashrut matter, still a problem today, is that even properly slaughtered and inspected meat must be drained of blood before being considered fit to eat. Usually, salting achieves that; however, as liver is regarded as "(almost) wholly blood", broiling is the only way of kashering. Properly broiling a foie gras while preserving its delicate taste is difficult, and therefore rarely practised. Even so, there are restaurants in Israel that offer grilled goose foie gras. Foie gras also bears resemblance to the Jewish food staple, chopped liver.