The term “soude” refers to both a historically important chemical compound and the plant from which it was derived. This plant, Salsola soda, is known as saltwort or barilla. It thrives in environments where most other plants struggle.
The Plant Behind the Name: Salsola soda
Salsola soda is an annual, succulent shrub, typically 5 to 70 centimeters tall and up to 46 centimeters wide. Its herbaceous stalks are often reddish-brown and lack thorns. The leaves are fleshy, hairless, and greyish-green, sometimes turning reddish, clasping the stem.
As a halophyte, this plant tolerates salty conditions. It thrives in coastal saline habitats and can even be irrigated with saltwater. Salsola soda is widespread in salty areas globally, especially along the Mediterranean Basin, and has been introduced to regions like South America and California. It accumulates inorganic salts and water in its tissues, enabling it to maintain osmotic balance and grow in high-salinity soils where other plants cannot survive.
From Ash to Industry: Historical Significance
Historically, Salsola soda was a primary source of soda ash, predominantly sodium carbonate. The process involved harvesting the plant, drying it, and then burning it to produce an alkaline ash. Water-soluble sodium carbonate was then extracted from these ashes via lixiviation, followed by boiling the solution to obtain the soda ash.
Soda ash played a role in various early industries. It was valued in glassmaking, contributing to the clarity of 16th-century Venetian cristallo glass. Additionally, soda ash was a component in soap production. Spain, for example, had a substantial 18th-century industry dedicated to producing soda ash from saltworts, which they called “barrilla”.
The widespread demand for soda ash for soap, textiles, and glass in the late 18th century eventually outpaced the supply from burned plants and seaweed. This led to synthetic methods, such as Nicolas Leblanc’s process (1791) and the more efficient Solvay process (1860s), which ultimately superseded plant-based extraction.
Modern Uses and Culinary Appeal
Today, Salsola soda has found renewed purpose, especially in culinary applications. It is known as “agretti” or “monk’s beard,” popular in Italian cuisine, and also called saltwort or friar’s beard. This vibrant, succulent plant is a spring delicacy, available from late winter to early spring (March to early June).
Agretti has a distinctive flavor, described as slightly salty, with a pleasant crunch and a hint of bitterness, sometimes compared to spinach, samphire, and chard. It is sautéed with garlic and olive oil and served as a side dish. Young, tender agretti can be used raw in salads, complementing ingredients like tomatoes, olives, and mozzarella. Traditional Italian preparations include incorporating it into pasta dishes, such as ‘Spaghetti con gli Agretti’ in Rome, or into omelets like ‘Frittata di Agretti’. The plant also contains nutrients, including vitamin A, iron, and calcium.