The basement of a century-old house owned by a long-deceased Thai doctor isn’t a likely place to find a cutting-edge cocktail bar. But Philtration isn’t your standard cocktail bar. 

Located on Kasemsan Soi 3, the speakeasy-style bar is serving drinks inspired by Boonmee Kasemsuwan, better known as Moh Mee, in an almost dungeon-like chamber. The house, and the basement itself, was built during Rama V’s reign. Part-house, part-factory, it was designed by the same Italian architects who designed the Ananta Samakhom Throne Hall. In the late 19th century, Moh Mee concocted herbal Chinese medicine in this very basement under lock and key. Later, the chamber was sealed by the family, until fourth-generation descendant Nachapol “Na” Kasemsuwan decided it was time to reveal this century-old secret to the world.

“The story of this house already exists. I’m just helping it resonate louder in the world,” Na says.

Inspired by the speakeasies he discovered while studying in the UK, Na saw the potential for this space to bring new energy to Bangkok’s bar scene. Three years after opening a restaurant called Baan Moh Mee within the compound, Philtration was born.

The interiors here, many of which were left intact, are all about soft curves, with an elegant east-meets-west vibe. The name Philtration, meanwhile, stems from the term “philtre,” or potion. That thread runs through the whole story of the space, from the history to the cocktail menu, based on herbal mixtures, extractions, and fermentation. 

“I was thinking of how we could express this knowledge in the modern world. [A speakeasy-style bar] was the right medium to bring the two things together—our tradition of herbal remedies and the trending concept of a hidden cocktail bar,” Na explains.

The two narrative forces combine under the direction of Shavinraj “The Fairy Godfather” Gopinath. He and his team played with herbs and spices used in their traditional remedies, as well as ingredients found around Thailand. They still do that, in fact. 

“We have to stay current, finding new ingredients and recipes to keep the menu fresh and playful. Guests always want to see something new and special on the menu when they return,” says Gopinath. 

To do that, they experiment with infusions and fermentation, keeping a tight grip on their flavor profile across an impressive list of 25 signature drinks. The highlights include the Opium Den (B400). Beyond the cheeky name, the drink is infused with herbal ingredients that boast anti-inflammatory properties. The Sam Kok (B380), meanwhile, has a base of Saint James rum and rose apple, which, in traditional Thai-Chinese medicine, is said to help with weight loss and reduce the risk of getting Alzheimer’s disease. 

Besides the unique setting and drinks, Na hopes to develop some staying power through live music and events. “It was always part of the plan,” he says. But it’s done in their own style. Last year, Filtration played host to Broadway-themed performances, for example.

“When we first announced it, the tickets sold out in three hours. The second time, tickets were sold out in three minutes,” Na says.

Now, Na plans to hold two to three events per month, with a new set of cocktails and theme each time, once bars can get back to business.

In the meanwhile, they’ve found new ways to keep busy. In March, they launched Dr. Phil, a brand of cold brew teas made with medicinal herbs. The selection includes drinks like Oolong Till Better (B100), infused with Uthai Moh Mee, an herbal blend said to help improve blood circulation and benefit the heart, and Rice Tea Meet You (B100). They are currently working on liquor-spiked jams, too.

“We aren’t doing this for ourselves but for our staff who have invested their hard work to make Philtration successful. Without them, it wouldn’t have been possible,” says Na. 

“We are currently in the R&D phase of finding our new identity,” adds Gopinath, a subtle nod to the scientific experimentation that runs through this historic space.

All images courtesy of Philtration.