Kelp burning was central to island and coastal life in Ireland from the early eighteenth century onward, peaking in the decades around 1800 when the ash was in high demand by the glass and soap industries on the mainland and further afield. The process involved gathering vast quantities of brown seaweed, principally species of Laminaria and Fucus, drying it over low stone structures, and then burning it slowly in long trench kilns to produce the solidified kelp ash. The kilns themselves are typically simple, elongated, shallow constructions of unmortared stone, built directly into the shoreline landscape. On the Aran Islands, where soil was scarce and agriculture precarious, the kelp industry offered one of the few reliable sources of cash income for island families, though the work was gruelling and the returns often slim. The collapse of the industry in the nineteenth century, undercut by cheaper synthetic sources of soda ash, left these kilns as the most visible physical trace of that labour.