Costco is incredibly popular for a reason, and the store brand products, Kirkland Signature, have something to do with it. At about $18 for a 1.75-liter bottle, the Kirkland Signature London Dry Gin, for example, is great to use with mixers like club soda, tonic, or in cocktails with juices or fruity ingredients.

Some consumers on Reddit, however, noted that the Kirkland gin has heavy rose notes, and suggested choosing another bottle if you're planning to have only one type of gin on your home bar cart. Although little has been confirmed or is known about Costco's gin — according to reports, it's quite possible that Tanqueray or Gordon's might be responsible for making it.

The bottle is reminiscent of Bombay Sapphire, but the number of gin distilleries owned by Diageo, the dryness of the gin, and the juniper notes — all seem to point to a Diageo distillery like Tanqueray or Gordon's. Distilleries typically don't want to claim that they are making another label for Costco, so this educated guess is as close as there is to an established answer.