Soda ash is one of the alkali substances that are crucial in glassmaking and soapmaking. The famed clarity of 16th-century cristallo glass from Murano and Venice depended upon the purity of "Levantine soda ash", and the nature of this ingredient was kept secret. Spain had an enormous 18th-century industry that produced soda ash from the saltworts (barrilla in Spanish).
Soda ash is an essential component in glassmaking and soap production. The distinctive clarity of cristallo glass from Murano and Venice in the 16th century was dependent on the purity of "Levantine soda ash", which remained a closely guarded secret. Spain's substantial industry in the 18th century focused on producing soda ash from saltworts.