Why Kelp?

The water in Kachemak Bay is cold enough to take your breath away, even in July. Glaciers feed it from the Kenai Mountains; tides pull it in and out twice a day. Beneath that turquoise-blue surface, kelp grows slowly through the dark winter months, ribbon by ribbon. It’s where our story begins. But the story of kelp and bathing is far older than Alaska.

An Old Ritual, Rediscovered

People have turned to the sea to restore themselves for as long as there have been coastlines. In Euripides' Iphigenia in Tauris, written in the fifth century BC, Iphigenia declares that "the sea washes away all the ills of mankind." It is a line about ritual purification rather than spa treatment, but it captures something that has never quite left the Western imagination: the sense that salt water renews.

France: the birth of thalassotherapy

That instinct gained a name in nineteenth-century France. On 31 December 1865, a young medical student named Joseph La Bonnardière defended his doctoral thesis at Montpellier, Introduction à la thalassothérapie, joining the Greek thalassa (sea) and therapeia (care). The word stuck.

In 1899, on a rock overlooking the Channel at Roscoff in Brittany, Dr Louis-Eugène Bagot opened the Institut de Rockroum, widely regarded as France's first thalassotherapy center. Bagot offered baths of heated seawater, jet showers and what he called wave baths, a kind of full-body massage by the sea itself. Brittany became the heartland of the practice, with marine therapies, including seaweed wraps and baths, eventually filling dozens of institutes along the French coast. Today, the Breton thalasso remains a byword for coastal luxury.

Ireland: the Edwardian seaweed bath

Across the water, the west of Ireland developed a ritual all its own: the hot seaweed bath. By the end of the Victorian era, bathhouses offering hot seawater and fresh seaweed stood in resorts like Enniscrone, Strandhill, Bundoran and Portrush. At the start of the twentieth century there were around 300 of them around the Irish coast, nine in County Sligo alone.

In 1912, the year the Titanic sailed, Kilcullen's Bath House opened in Enniscrone, County Sligo. More than a century later it is still run by the same family, its enormous porcelain tubs, brass taps and wooden steam cabinets unchanged. The ritual is simple and slightly theatrical: a steam, a long soak in hot seawater thick with freshly steamed seaweed (serrated wrack gathered from Killala Bay), then a bracing cold seawater shower. Locals came after the harvest to soothe tired bodies; today travelers come for the sensation of skin that feels silky for hours afterward.

Japan: the gift of the sea

In East Asia, seaweed has been woven into daily life for well over a thousand years, first as food and offering. Japan's ama, women who free-dive without breathing equipment for abalone, shellfish and seaweed, appear in historical records from the eighth century; some scholars estimate the tradition is close to 2,000 years old. Kombu appears in the Shoku Nihongi, a court chronicle completed in 797, in an entry for the year 715 describing kombu offered as tribute to the imperial court. By the tenth century, the Engishiki listed kombu as a tax item, destined for sacred offerings to the gods and the emperor's table.

Korea: a bowl for new mothers

In Korea, seaweed holds a tender place in the rituals of birth. Women traditionally eat miyeok-guk, a gentle seaweed soup, for weeks after giving birth, and Koreans eat it on their birthdays in honor of their mothers. Tradition traces the custom back to the ancient kingdom of Goguryeo. It is a ritual of nourishment rather than bathing, but it speaks to the same idea: that seaweed is a food of care and restoration.

China: the classical materia medica

China's oldest surviving pharmacological text, the Shennong Bencao Jing (Divine Farmer's Classic of Materia Medica), compiled around the turn of the first millennium, records haizao, seaweed, among its marine substances. Later classics added kunbu, a name for large brown kelps, which first appears in the Wu Pu Bencao of the Wei and Jin period. Kelp has been traded and treasured in China for more than a thousand years.

Different coasts, different rituals. The common thread is a deep cultural trust in what grows in cold, clean seawater.

The Science of a Kelp Bath

Kelp is a large brown seaweed, and what makes it so remarkable in the bath is what it is made of.

• Alginate. The signature polysaccharide of brown seaweeds. Alginates hold water and form a soft, slippery gel, which is why kelp feels silky between your fingers. It is the same quality Irish bathhouse keepers describe when they steam seaweed to release its alginates.
• Fucoidan. A sulfated polysaccharide found in brown seaweeds and increasingly studied in cosmetic science for its skin-conditioning properties.
• Minerals and trace elements. Growing in seawater, kelp concentrates minerals such as magnesium, potassium, calcium and iodine within its fronds.
• Moisture-binding polysaccharides. Together, these long-chain sugars behave like natural humectants, attracting and holding water.

In warm water, a kelp bath releases these compounds into a gentle, faintly silky soak. The result is a sensation many bathers know from the Irish seaweed bath: skin that feels softer, smoother and more supple, with a conditioned, hydrated feel that lingers after you step out. A seaweed bath is not medicine. It is a ritual of comfort, and kelp for skin is, at its heart, about how your skin feels: soft, cared for and calm.

Why Alaskan Kelp

Kelp thrives in cold water. Alaska has the longest coastline in the United States, more than five hundred species of seaweed and some of the largest kelp beds in the world. For centuries, Alaskans have gathered seaweed for food and materials. What is new is farming it.

Alaska's first commercial kelp farm was established in 2016. Since then the industry has grown quickly, with harvests reaching a record 872,000 pounds in 2022. Kelp farming requires no fresh water, no fertilizer and no arable land: farmers seed lines in autumn, and the kelp grows through the cold, dark months to be harvested in spring.

Our kelp is sustainably farmed in Kachemak Bay, near our home in Homer, Alaska. Here, glacial meltwater and nutrient-rich tides meet in one of the most productive marine environments on the coast. Native sugar and ribbon kelps grow slowly in this cold water, and we believe you can feel it. Alaskan kelp is a small, clean, quietly radical thing: a crop that asks nothing of the land and gives back to the sea.

The Seavīta Ritual

We created our Deep Sea Mineral Soak to bring a century-old coastal ritual home, rooted in our own cold bay.

Run a bath as hot as you can stand it. Pour in Zechstein magnesium flakes, 16 ounces of a mineral drawn from an ancient sea, and let them dissolve. Drop in the kelp and botanical bath tea bag and watch the water soften around it. Finish with a few drops of Deep Drift, our vetiver body oil, earthy and grounding, on damp skin after you rise.

Then stay a while. Let the steam rise the way it does off the bay on a cold morning. No schedule, no screen, just water, salt and kelp, doing what they have done for people across the world for centuries.

When you are ready, the Deep Sea Mineral Soak is waiting.

Sources

• Euripides, Iphigenia in Tauris, line 1193.
• CTHS, "La Bonnardière, Joseph"; Bibliothèque nationale de France (HAL) on La Bonnardière's 1865 thesis.
• Les Echos, "Roscoff, berceau de la thalassothérapie" (2017); HAL thesis on Breton thalassotherapy, 1899–1998.
• Kilcullen's Seaweed Baths, "About"; Ireland.com, "Seaweed baths and County Sligo"; BBC Travel (2014); The Irish Times.
• Japan Tourism Agency, "The Ama of Ise-Shima"; National Diet Library of Japan, "Kaleidoscope of Books" No. 17.
• FAO, "Laminaria mariculture in China"; Chinese pharmacology literature on haizao and kunbu.
• Alaska Sea Grant, "Aquaculture"; USDA Climate Hubs, "Seaweed Farming in Alaska"; NOAA Fisheries, Alaska mariculture overview (2025).