Kettle Sour with Phantasm

There has been a lot of experimentation around thiols in recent years, but much of it has been centered around the interactions between thiols and hops with a focus on pale ales and IPAs. We thought about ways to make thiols shine rather than compete for the spotlight, and a tart, fruity beer seemed like an interesting idea. For this recipe, we chose a kettle-soured Berliner Weisse as our starting point but modified it to encourage more thiol production by incorporating precursors and thiol-generating yeast.

A traditional Berliner Weisse recipe will typically include a fair amount of wheat, often about half the grist or more. However, our research has indicated that barley is a much more reliable source of thiol precursors, so we cut down the wheat to only about 10% of the grist in this recipe. The high percentage of barley will give our Thiolized® yeast additional precursors to chomp on and create those rich passion fruit aromas we’re looking for.

Phantasm is an extract made from New Zealand sauvignon blanc grape skins that increases the amount of thiol precursors in your wort. Since we would not be using many hops at all in this recipe, we wanted to see how an extra push from the Phantasm would crank up the thiol flavors in the finished beer without much aroma competition from the hops. Adding Phantasm during the whirlpool stage will add precursors to your wort and should help with clarity as well.

As with any kettle soured beer, we did an initial souring with our Lactobacillus blend before pitching our Thiolized® yeast, Star Party. We opted for Star Party over the other Thiolized® strains to lay a clean and well attenuated base to spotlight thiols and lactic acid. Remember: any IBUs will inhibit the Lacto blend, so no mash hopping.

The finished product was fascinating — the inclusion of Phantasm generated a strong thiol-forward aroma note, but the most interesting aspect was this beer’s wine-like quality. The clean sourness combined with strong sauvignon blanc flavor notes made this a refreshingly tart crusher that our staff really enjoyed. We see this as a great opportunity to take thiol-forward brewing in a new direction, and encourage brewers to take some risks and find different ways to incorporate thiols into their beers beyond pale ales and IPAs.