When I visited friends in Madrid two summers ago, we did our share of drinking. We sipped sherry and house-made vermouth alongside tapas, took in World Cup matches over one-Euro beers, and toasted fancy gin cocktails. Just about the only thing I didn’t drink a lot of was whiskey; it’s distinctly unpopular in Spain, despite that nation’s rightful reputation as a hotspot for drinking. American whiskey, especially, is scarce.

The one bourbon you can reliably find in Spain is Four Roses. This is because in 1943, when Seagram acquired the brand, they stopped selling Four Roses bourbon in the US and…