A new R&D Series release from Ninkasi Brewing Co. is being released exclusively for a special event.

The beer is named Grapefruit Sour, a 5 percent ABV kettle-soured ale that is brewed with grapefruit puree. The new ale is part of the Eugene, Ore.-based brewery’s Rare & Delicious Series, which are beers that are “the creative expressions of each member of our brewing collective” and also includes Tart & Soul (5 percent ABV), Sour of Love (5 percent ABV) and Mango IPA (7.2 percent ABV) among others.

As for the the Heavy Kettle Project designation, “we decided to develop this framework for all Ninkasi sours to fall under,” Ali AAsum, communications director at Ninkasi, told Tenemu in an email. “It’s a play on our love of everything metal and the style of the beer (an American Kettle Sour).”

Ninkasi Grapefruit Sour Keg Label

According to AAsum, Grapefruit Sour will be a draft-only release that is scheduled to be poured exclusively at the Oregon Brewers Festival taking place in Portland from July 27-30. In addition, although a 22-ounce bottle label was submitted to the Alcohol and Tobacco Tax and Trade Bureau (TTB), the brewery has no plans of bottling the beer at this time.