"Mochaware invented in the 1790s, probably by accident, and much exploited for more than a century for utilitarian beer, mugs and jugs. The technique consisted of dripping a special 'tea' composed of acidic tobacco juice, manganese and, by tradition, stale urine onto a surface freshly diped in coloured alkaline clay slip. The reaction between the acid and alkali would spread the brown mixture into frond-like forms resembling the Mocha Stone from Arabia, which to a certain extent could be controlled by a skilled potter. The lathe turned rims and feet were usually finished with simple trailed bands of slip."
Source: Pg. 226 English Pottery 1620-1840 by Robin Hildyard"