In an episode if Frasier, Frasier Crane is dating a Jewish woman and is suddenly forced to meet them. While his girlfriend at the time didn't create about him not being Jewish, her family would so he pretended to be Jewish, forcing him to take down Christmas decorations and serve Jewish foods. However he didn't have Jewish wine, so his brother poured a glassof regular wine and added a heaping teaspoon of sugar to it.
So, I was wondering, why is Jewish wine different than regular wine and was there a historical reason to this? Was wine once sweeter as well?
It actually doesn't have much of a historical reason. The most popular kosher wine in the US is Manischewitz wine, and they add sugar to their already-sweet wine. Frasier is playing off this stereotype. But kosher wine need not be sweet; I'll let someone else answer about historic Jewish wine.
This exists for a particular historic time and place. Traditionally, there was nothing particularly sweet about Jewish wine. However, in order to have kosher wine, there are a number of procedures that need to be followed, resulting in Jews being pretty much the only people who grow kosher wine. As Jews emigrated to the United States, the population was predominantly found in New York, and Jewish businesses, including the kosher food industry, centered around there. However, the only grape that would grow in the New York area, especially before more modern cultivation techniques, is Concord grapes, which are rather sweet and don't have the best flavor. But that was what available. This is the main grape used by everyone to make grape juice and grape jelly, due to its sweetness. So the end result was that kosher wine in the New York area, and then across all of the US, came to be made with sweet Concord grapes, and then a stereotype formed around Jewish wine being sweet, in the 20th century. But there's no history of it nor any Jewish reason why it must be so. I've lived in France, and there are kosher wines of all varieties there. They scorn the poor quality sweet kosher wine that Manischewitz makes. It certainly doesn't need to be true any more, but people have grown used to it and it's become a tradition. There's no huge Jewish tradition of drinking or interest in alcoholic beverages, so there's never been any huge Jewish movement to have better wine--if you're not too religious, you'll drink any wine that interests you and don't have to concern yourself with it being kosher. If you are religious, then you'll only drink kosher wine and you're not going to spend too much time fretting over the secular practice of drinking wine as a leisure activity.