When Brent Delman was growing up in Cleveland, his culturally Jewish family, like their Eastern European forebears, ate lots of soft, fresh cheese—cream cheese, sour cream, cottage cheese—without worrying much about whether it was kosher. After all, cheese is just curdled milk, and as long as it’s not eaten with meat, what could be treif about it?
In some cases, it is that simple—at least for the soft cheeses common to traditional Eastern European cuisines. As long as the other ingredients (the bacteria cultures, acid and salt) are kosher and the cheese is prepared using sterilized equipment, these cheeses are considered kosher (and many carry kosher certification).
But as Delman—a specialty foods supplier—learned when he went into business making and selling kosher cheese as The Cheese Guy in 2008, hard cheeses such as gouda, cheddar and blue cheese are another story. “It’s all about the rennet,” Delman says. Historically, rennet —a complex of enzymes found in the lining of a calf’s stomach—was required to coagulate milk and ripen it into hard cheese.