Bittermilk is a craft cocktail mixer brand offering bourbon barrel-aged blends like its No. 1 Old Fashioned and No. 5 Charred Grapefruit Tonic. The brand's lineup extends to espresso martini mixer, Manhattan mix, and margarita mixer, all crafted with all-natural ingredients. Bittermilk brings elevated, small-batch quality to cocktail creation at home.