Before me sit two new beers from Belleflower Brewing and Mast Landing, the fruits of a recent collaboration. Their names – As the Siren Sleeps and Encountered by Argonauts – suggest I may need to brush up on my classical mythology.

The Argonauts were Greek heroes, about 50 in number, who joined Jason aboard the ship Argo, in quest of the Golden Fleece. On their return voyage, they had to sail past the Sirens, whose irresistible songs drew sailors to their island; there the sailors would stay, eventually dying of hunger, so captivated they were by the monsters’ sweet music. But among the Argonauts was Orpheus, the world’s greatest musician. He would keep the crew safe, his lyre drowning out the beautifully fatal song of the Sirens.

It’s fair to say that each of these New England IPAs sings an enchanting tune, and both are deadly tasty.

As the Siren Sleeps (7.3% ABV), from Belleflower, pours a pale, hazy gold. Double dry-hopped with HBC586 and Bru-1 LupoMAX pellets, it is a swirl of aromas and flavors: pineapple, watermelon, citrus, guava and white wine. The mouthfeel is soft and almost creamy, and it finishes with a restrained, pleasant bitterness.

Encountered by Argonauts (7.2% ABV), from Mast Landing, is orange-colored in the glass. A lineup of Citra, Talus, Hallertau Blanc, Idaho 7 hops make for a tropical cocktail of marmalade, white wine, a hint of tangy kumquat and a touch of coconut. Its sweetness is tempered by a moderately bitter finish.

As the Siren Sleeps, a collaboration between Belleflower and Mast Landing brewing companies. Photo courtesy of Belleflower Brewing Co.

Each is quite distinctive in its own right, constructed through different hop and grain bills, while also distinguished by each brewery’s house yeast. But they do share one unifying ingredient in particular. The explosive fruitiness of both beers is enabled by Phantasm, a compound derived from Sauvignon Blanc grape skins. Phantasm is (and bear with me here) a “thiol precursor.”

Enter Weston Shepherd, production manager at Mast Landing, for a chemistry lesson. According to Shepherd, thiols are “potent aromatic sulfur compounds that are molecularly similar to alcohol.” Some smell good, like those in hops, which can add aromas of grapefruit and guava. Others smell bad, like those rotten-eggs scents added to odorless gasses so you know if your stove is leaking. While you can smell “free thiols,” thiol precursors (or “bound” thiols) are larger and are chemically bonded so that we can’t smell them. But yeast can “unlock some of these aromas,” Shepherd says.

“Thiol precursors are basically flavor compounds that yeast can biotransform into other flavor compounds,” explained three of Belleflower’s owners – Katie Bonadies, Nick Bonadies, and Zach Page – via an email exchange. Using Phantasm, they explain, gives their yeast “the tools it needs to increase the perception of hoppy-ness and to layer in complex fruit forward flavors.”

Both breweries added Phantasm to the “whirlpool” – the process when debris, gloriously named “trub,” is separated from the wort, post-boil. And from there, the yeast went to work, “unlocking” some of the “characteristic aromas” of Sauvignon Blanc wine – guava, pink grapefruit, gooseberry and passionfruit – according to Shepherd.

While Phantasm provides the genetic link between these sibling beers, the design and concept – pivoting around the mythological coming together of the Argonauts and the Sirens – constructs an imaginative world around them.

“Much like the recipes, there is a core similarity between the two names,” said Gene Buonaccorsi, Mast Landing’s director of marketing, “but we approached the myth of the sirens from a different vantage point.”

Indeed, the cans share a visual template – a nautical scene viewed through a lancet window – but each is also distinctive, like the beers they hold. The setting for Encountered by Argonauts – designed by Parker Olen, a co-owner of Mast Landing and its vice president of brand strategy – is verdant and sunny, the Argo well within earshot on a balmy day. As the Siren Sleeps – designed by Allie Norman for Belleflower – strikes a more somnolent tone, the silhouette of the ship distant in the gloaming, the mysteries of the darkness hidden.

Which is Orpheus’s lyre, and which is the Sirens’ song? I think of Butes, the one Argonaut to leap overboard, incapable of resisting the Sirens. Bobbing in the water, he heard both the song of the Sirens and harp of Orpheus at once.

Ben Lisle is an assistant professor of American Studies at Colby College. He lives among the breweries in Portland’s East Bayside, where he writes about cultural history, urban geography, and craft beer culture. Reach him on Twitter at @bdlisle.