Kool Sonic Fruit Juice, a layered sour beer, was masterminded by Ground Up brewers Oli Boyes and Julian Webster, of Wanaka, after they saw a similar creation by Wellington brewers Garage Project a few months ago.
Upon their return, they set about trying to mix two of their sour beers, Kool Juice, a sweet 5.5% beer made with lactose, and Sour Fruits, a drier 6% alcohol beer.
While a spoon-like contraption had to be added to the tap of the Sour Fruits to stop it breaking through the Kool Juice, the idea worked after two months of experimenting.
"The high-residual sweetness in the Kool Juice underneath makes it heavier while Sonic Fruits is drier and more alcohol, and those two factors mean it layers really really nicely," Mr Boyes said.
Nitrogen was also infused to create a third colour, being the white foam on top.
"We’re using a lot of science. People might think there’s not a lot involved in making a beer but it really is quite indepth."
Aside from what they saw at Garage Project and a couple of others in the United States, Mr Boyes said their layered sour beer was "definitely" unique to the South Island.
"Most people won’t ever have seen something like this before."
The pair debuted the beer at last weekend’s Dunedin Craft Beer & Food Festival, and Mr Boyes said it was their fastest-selling beer because it was different.
The beer will also be showcased at the Wanaka Beer Festival next month, and could also be on tap at Cork Bar in Wanaka soon, he said.
