While most grain-based spirits are in fact kosher, few are actually certified. The ingredients added into the stills can sometimes keep spirits from said certification. For example, the cardamom used in 209′s regular gin isn’t kosher. Neither are the port and sherry that sat in the barrels that many whiskeys are aged in. It goes without saying that it’s difficult to find kosher liquor, but thanks to some craft spirit makers, it’s not impossible.

Some companies like Distillery 209 have started specifically crafting kosher products like the No. 209 Kosher for Passover Gin. Miami-based branding specialist Ralph Mizraji just came out with L’Chaim corn-based kosher vodka, too.

Source

Kosher-for-Passover Gin: bring on the martinis, LA Times
Toast Hanukkah with kosher spirits, Bloomberg Businessweek