That these kilns are considered archaeologically significant at all often surprises people, yet they were once as essential to a farming community as the fields themselves.

A lime kiln was a simple but demanding piece of infrastructure. Limestone and fuel, usually coal or timber, were loaded in alternating layers into the bowl of the kiln and burned at intense heat over the course of several days. The resulting quicklime was then spread across fields to reduce soil acidity, a practice that transformed boggy or sour land into productive ground. The spread of lime kilns across Ireland from the seventeenth century onwards tracks closely with agricultural improvement movements, landlord schemes, and eventually the intensified tillage demands of the eighteenth and nineteenth centuries. Many were built close to local limestone outcrops to reduce the cost of hauling raw material, and the best-preserved examples retain their arched draw-holes at the base, through which the burned lime was raked out. The Glentrasna kiln is one of many such structures still dotting the Cork countryside, most of them now cold and overgrown, their working lives having ended when commercial lime became cheaper and easier to obtain than burning your own.