Crooked Stave Artisan Beer Project will celebrate Roy G. Biv on Sunday with a bottle sale, a party and a couple of rare beer tappings at the Barrel Cellar.

Roy G. Biv isn't a person, though (if it was, he'd be very sour). Rather, it's an acronym for the seven beers that Crooked Stave has brewed over the past two years as part of its color-themed Wild Wild Brett series. The final beer, Violet, will be released on Sunday.

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"We brewed it back in January, so it's been a long time in the making," says Crooked Stave founder Chad Yakobson. Brewed with pomegranate and lavender, the beer was then fermented 100 percent with brettanomyces yeast and aged in oak barrels with passion fruit pulp. And although the passion fruit gives it a "tart character," Yakobson didn't use souring agents or bacterias in Violet.

After fermentation, Violet was dry-hopped with an experimental strain of hops known as 366. "We asked the growers in the Yakima Valley to send us something that reminded them of violet or purple or grape-y colors," Yakobson explains.

"We smelled a few that they sent us and went with 366. It has a purple, grape-y note that plays well in the background. You have to look for it, though," he adds.

Like the other Wild Wild Brett beers, Violet will be sold in 750 ml bottles, but it's the last Crooked Stave beer that will be packaged that way for a while, as the brewery has switched to using 375 ml bottles.

Unlike the other beers in the "Rainbow" series, it won't be sold in stores. All the bottles will be sold from the taproom beginning at noon on Sunday; there will be a six-bottle limit.

And beginning at 1 p.m., Crooked Stave will tap limited amounts of all of the other beers in the series, a new one each half hour (Rouge, Orange, Yellow, Green, Blue, Indigo). Wild Wild Brett Violet, along with two other Crooked Stave beers, St. Bretta and Hop Savant, will be on tap all day.

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