The timing of Bittermilk's fifth release couldn't be better: With Charleston palates already tuned to grapefruit by Radler, the local bottled cocktail mixer company is putting out a charred grapefruit tonic.

In addition to burnt grapefruit, the compound features lime and lemon juices, cinchona bark, sugar and Bulls Bay Saltworks salt.

Salt was added to "really bring out the savory caramel notes and to round out the flavor," Joe Raya is quoted as saying in a release. Raya and his wife, MariElena, last year created the Bittermilk brand.

Unlike other mixers in the Bittermilk line, the No. 5 is not merely a just-add-spirit proposition. Although the tonic could probably hold its own with tequila or gin, the directions urge drinkers to reach for a bottle of club soda too. Still, promotional materials maintain the product is a "tonic not available in the market."

In addition to grapefruit tonic, Bittermilk is continuing to offer its Old Fashioned, Whiskey Sour, Sazerac and Tom Collins mixers, all of which are enhanced with various aromatics and botanticals. The tonic is the first concoction centered on citrus.

"We are excited to launch this line in the middle of the summer-a perfect time for the refreshing drink," Raya says.

No. 5 will officially launch next month at Two Boroughs Larder's third anniversary party. The Aug. 3 event at Deux Puces Farm will feature a raw bar and Cathead Vodka cocktails from 1 p.m.-4 p.m., followed by a $55 dinner at 5 p.m. The cocktail afternoon costs $10. To purchase tickets, visit event.celebrations.com/Larder3YearParty.

Bittermilk products are sold at local retail outlets including Caviar & Bananas, Charleston Beer Exchange, Two Boroughs Larder and High Wire Distilling Co. For more information, visit bittermilk.com.