Theglassworts are various succulent, annualhalophytic plants, that is, plants that thrive insaline environments, such as seacoasts andsalt marshes. The original English glasswort plants belong to thegenusSalicornia, but today the glassworts include halophyte plants from several genera, some of which are native to continents unknown to the medieval English, and growing in ecosystems, such asmangrove swamps, never envisioned when the term glasswort was coined.
The common name "glasswort" came into use in the 16th century to describe plants growing in England whose ashes could be used for makingsoda-based (as opposed topotash-based)glass.[1][2]
The ashes of glasswort plants, and also of their Mediterranean counterpartsaltwort plants, yieldsoda ash, which is an important ingredient forglassmaking andsoapmaking. Soda ash is analkali whose active ingredient is now known to besodium carbonate. Glasswort and saltwort plants sequester the sodium they absorb from salt water into their tissues (seeSalsola soda). Ashing of the plants converts some of this sodium intosodium carbonate (or "soda", in one of the old uses of the term).[citation needed]
In the medieval and early post-medieval centuries, various glasswort plants were collected at tidal marshes and other saline places in the Mediterranean region. The collected plants were burned. The resulting ashes were mixed with water. Sodium carbonate is soluble in water. Non-soluble components of the ashes sank to the bottom of the water container. The water with the sodium carbonate dissolved in it was then transferred to another container, and then the water was evaporated off, leaving behind the sodium carbonate. Another major component of the ashes that is soluble in water is potassium carbonate, a.k.a. potash. The resulting product consisted mainly of a mixture of sodium carbonate and potassium carbonate. This product was called "soda ash" (it was also called "alkali"). It contained 20% to 30% sodium carbonate. For glassmaking, it was superior to a potash product obtained by the same procedure from the ashes of non-salty plants. If plant ashes were not washed as just described, they were still usable in glassmaking but the results were not as good.[citation needed]
The appearance of the wordglasswort in English is reasonably contemporaneous with a 16th-century resurgence in English glassmaking, which had suffered a long decline after Roman times.[3][4] This resurgence was led by glassmakers who emigrated to England fromLorraine and fromVenice. The Lorraine glassmakers brought with them the technology offorest glass, the greenish glass that usedpotash from wood ashes as a flux. TheVenetian glassmakers brought with them the technology ofcristallo, the immaculately clear glass that usedsoda ash as a flux. These glassmakers would have recognizedSalicornia europaea growing in England as a source for soda ash. Prior to their arrival, it was said that the plant "hath no name in English".[2]
By the 18th century,Spain had an enormous industry producing soda ash from saltworts; the soda ash from this source was known asbarrilla.[5]Scotland had a large 18th-century industry producing soda ash from seaweed. The source of this ash waskelp. This industry was so lucrative that it led to overpopulation in theWestern Isles of Scotland, and one estimate is that 100,000 people were occupied with "kelping" during the summer months.[6] In the same period, soda ash (la soude de Narbonne) was produced in quantity from glasswort proper aroundNarbonne, France.[7][8] The commercialization of theLeblanc process for synthesizing sodium carbonate (from salt,limestone, andsulfuric acid) brought an end to the era of farming for soda ash in the first half of the 19th century.[citation needed]
.jpg)
Young shoots ofSalicornia europaea are tender and can be eaten raw as a salad:glasswort salad orsamphire salad (Turkish:Deniz börülcesi salatası). This salad is a part ofTurkish cuisine, also made with lemon juice, olive oil[9] and garlic.[10][11] It is commonly served as ameze.[citation needed] The shoots can also be pickled.[12]
The plant can further be prepared in several ways – cooked, steamed, or stir fried – and eaten as a vegetable dish.[13]
Plants that have been called glassworts include:
