A Maine Bartender Inspired by the Ocean

How Wild Ingredients and Chemistry Are Revolutionizing Cocktails at Magnus on Water

Image of Cat applying foam to a Couch Surfer is courtesy of Magnus on Water.

On any given morning in late summer, Brian “Cat” Catapang can be found in Clifford Park beside a blackberry patch in Biddeford, Maine. Unhurried, he breathes in the fresh air, his fingers stained a deep reddish-purple as he fills a bucket with berries. Cat then travels the short distance to Magnus on Water to juice the blackberries and steep them in salt he’s extracted from pails of seawater hauled at high tide from nearby Fortunes Rocks Beach. For three days, the mixture dries on low heat in dehydrators in the restaurant’s basement, preserving its volatile aromas. Finally, Cat grinds the salt fine. This ingredient will become part of a drink he calls the Black Mamba.

Cat, the Beverage Director and Co-Owner of Magnus, is less a bartender than a modern alchemist, coaxing tinctures and syrups from whatever the landscape offers and testing them with the curiosity of a chemist at play.

This kind of innovation and care extends throughout Magnus—service, bartending, and cooking are all in sync, everything moving with the rhythms of the coast, the woods, and the waterways. It’s something akin to what surfers call the flow state—that fleeting moment when everything coheres. The shaker keeps its rhythm, the chime of ice against glass, the faint citrus bloom in the air. Everything is interconnected. Behind the bar, Cat seems to vanish into the movements, wholly absorbed. He is an astronaut, suspended somewhere between gravity and grace. And the first sip of his drinks land with a sense of inevitability of a tide rolling in.

For the Maine-born bartender, the sea is part of his identity, a force that shapes his work, pushing Cat to draw constantly from nature. Harnessing the ancient elements of earth, air, fire, and water into the flow of everything in the restaurant.

The water here has always been special. It’s a source of creativity. Child’s play. So much of what I create, and the kind of hospitality we try to offer, comes from that—curiosity, fun, a little mischief. But it always connects back to nature, using humble science. - Cat

Appropriate, then, that the restaurant takes its name from Albertus Magnus, the 13th-century German monk who was among the first to practice alchemy—the medieval forerunner of chemistry—blending science and mysticism to probe the natural world.

Image of the Couch Surfer courtesy of Magnus on Water.

The Couch Surfer and science

Amy Keirstead, a chemistry professor at the University of New England, recently spent an afternoon with Cat exploring the science of cocktails—how understanding ingredients and the ridiculously tiny things like atoms and molecules from which they are formed opens the door to more complex flavors and invention. After all, in the end, everything on the bar, even water, is a chemical.

To kick off the conversation, Cat began making the drink he is best known for—the one drink that never leaves the menu—the Couch Surfer. The cocktail is Cat’s homage to the zen of cold-water surfing. It begins as a variation on the margarita—a 50/50 blend of tequila and mezcal, lemon, lime, and orange, topped with a salty pineapple-poblano foam, and served in a glass shaped like a wave.

The Couch Surfer is a story that starts light, floating at the surface, before spiraling down into the depths—bracing, elemental, and even a little demanding, until it opens into something calmer and more rewarding.

It was the first thing I created. I wanted to capture that childlike moment of diving into a wave. The salty, frothy whitewater hitting your face, but then you dive under the waves and it’s refreshing and cooling and calm. It’s my homage back to Maine, to growing up here. Everyone can connect to playing in the ocean. - Cat

Ice melting dynamics

With the Couch Surfer, the goal is to let the tequila speak. It calls for an icy chill, encouraging it to be imbibed swiftly. Cat’s shake is restrained; he keeps the cubes intact. Ice, after all, does more than cool—it governs dilution.

Large blocks, hand-cut at Magnus, melt slowly, keeping flavor concentrated. The balance is delicate: too much chipped ice, and halfway through you’re sipping water with a memory of tequila.

“You want to look at your drink and it’s inviting,” Cat says. “I want it to be a work of art. It’s such a fleeting moment. It brings you into the present—and then it’s gone.”

The foam

Learning to catch and ride a wave takes courage, endurance, and patience. So does making cocktails at Cat’s level—emphasis on the patience, plus a lot of trial and error. He refers to mistakes as “portals to discovery.” Foams are one of Cat’s favorite tools: dense and rich or light and airy, often dismissed as trendy, but powerful when used with intention. His Couch Surfer features a seafoam-inspired cap, not as a decoration but as part of the drink’s story—an integration of flavors, not a layer.

He tried building the foam with fresh pineapple juice and sea salt, using egg whites as the emulsifier (a chemical bridge) to hold the ingredients together and lend a creamy texture and silken body, but the foam kept fracturing. Cat then tried xanthan gum (an emulsifier sold in powder form as a result of drying out sugars) as a binding agent in the drink, but the more he added, the more it just clumped together. Then one day he used a Vitamix to blend the ingredients, and the heat from the blade activated the xanthan gum, which “glued” together the starches, and the foam held its shape.

Xanthan gum, Professor Keirstead explained, is a polysaccharide (sugar polymer) used like an emulsifier and to increase viscosity.

You can use it to add to egg whites and it'll stabilize those. Which is exactly what you did in place of the egg yolks. The reason you needed to heat the xanthan gum was because of its structure—this part of the polymer (she points to an image in a scientific article) carries a negative charge and this part is neutral. It forms these strong forces, called electrostatic interactions, with itself and makes a coiled structure. You need the heat to overcome those intramolecular forces, to get it to stop interacting with itself and start interacting with the other ingredients. - Professor Keirstead

Image of the Cool Hand Luke by @mkaverill courtesy of Magnus on Water.

The art of mistakes

Cat treats mistakes as raw material. A failed experiment rarely ends in failure; more often it leaves him with a new technique tucked away until the right drink calls for it.

To him, cocktails are stories with characters—the flavor, the glass, the name—but it’s the chemistry, the decisions, the techniques that give them plot and spine. He revisits recipes like chapters, adding perspective, extending their arc. “And stories, like cocktails, are never truly finished,” Cat says. “I often revisit an old recipe with new perspective and techniques, breathing fresh life into it and extending its arc.”

Cat explains that he often pushes against the grain, testing the edge between expertise and discovery. For him, mistakes are essential—you have to make all the bad cocktails before you can make the good ones. Mastery of technique and flavor frees him to try combinations that make little sense on paper but reveal themselves in the glass. Balance, a word he finds as hollow as “smooth,” is not the goal. Drinks should evoke emotion: a nightcap can lean sweet or sharp and acidic, and both still achieve their own kind of equilibrium.

The Old Fashioned, in his eyes, is the perfect lesson. Its role is simple: let the whiskey shine. “Too often, bars stir the cocktail down to full dilution—ice-cold and waterlogged—only for the guest to be sipping whiskey-flavored water halfway through,” he says. Cat insists it should evolve in the glass—biting at the start, softening with time and ice. “Dilution and temperature are crucial here: bourbon is packed with fatty-chain esters that contribute complex aromas and flavors, but high ethanol masks them,” he explains. “Dilution slowly eases the proof, coaxing those subtler notes into focus. Over-stirring, on the other hand, makes the liquid too cold and “tight”—like an accordion compressed instead of stretched.” Understanding these details is what Cat says makes the Old Fashioned, in his eyes, a perfect drink. “It reflects patience and the passage of time,” he shares. “PSA to bartenders: stop turning your whiskey into water.”

Image of the Black Mamba courtesy of Magnus on Water.

Black Mamba

The cocktail itself is a Technicolor portrait of Cat’s process—blanco tequila blended with pear eau de vie from Bartlett Spirits of Gouldsboro and syrup made from caramelized citrus. Cat finishes it off with a little bit of Japanese sparkling yuzu and the blackberry salt mixture—a deep, vibrant pinkish-red-colored magical dust made from ingredients he foraged himself, anchoring the drink back to the land and sea.

Blackberry chemistry

Blackberries are generally small, juicy fruits with a sweet and tart flavor that are intense in color and packed with nutritional benefits. Blackberries are a source of phytochemicals (pigment compounds) called anthocyanins, which give blackberries their unique purple-black coloration.

Professor Keirstead pulls out a sheath of pages, each covered with intricate chemical structures that might look like hieroglyphics to anyone outside a lab. To her, though, they are a language.

They are sketches of molecular structures.

They show cyanidin 3-glucoside, the predominant anthocyanin in blackberries, and cyanidin 3-diozalylglucoside, a rarer compound thought to be unique to blackberries.

See all of these lines in each of these structures - these represent what we call a conjugated pi system– that’s a type of electronic arrangement that results in the molecules absorbing yellow light [points to a graph called an absorption spectrum] which means those compounds reflect other energies of the visible spectrum and appear purple. - Professor Keirstead

Final thoughts

So many of us fear the unknown. But I think, and Cat agrees, I’m sure, that’s the most exciting part of life. Exploring the dark recesses of our own psyches, embracing mystery, finding the next wave, and seeing where it takes you. There’s true creativity in what Cat is doing with cocktails.

🍸🥃🍹

Magic is for Everyone

Magnus on Water
12 Water St., Biddeford, Maine
Reservations highly recommended.
Reviews and past articles

Further Reading:
The Drunken Botanist: The Plants That Create the World’s Great Drinks by Amy Stewart

Liquid Intelligence: The Art and Science of the Perfect Cocktail by Dave Arnold

Also, check out the delicious finds at Rabelais (Portland, Maine), Omnivore Books (San Francisco, but ship nationwide USA), and Kitchen & Letters (NYC, but ship nationwide USA).