If you're not yet familiar with Jewniverse, now's the time. You may like to get into this article about kosher whiskey.
But obtaining the certification isn’t easy. Over the years, distilleries acquire hundreds of oak casks for aging their whiskey, and their origins are generally unknown. Many of the casks are assumed to have housed sherry in the past, which, as wine, is subject to much stricter kashrut scrutiny. So kosher scotch-makers like Glenmorangie have to know exactly what’s been in their casks.