The one at Drummeen, in County Clare, is a quiet example of a type that appears so frequently in boggy, low-lying ground that farmers and walkers have been stumbling across them for centuries without always knowing what they were looking at. They typically take the form of a horseshoe-shaped mound of fire-cracked stone and charred earth, built up over time beside a trough or pit, and their very ordinariness is part of what makes them so intriguing.

The prevailing interpretation, developed largely in the twentieth century, is that fulachtaí fia were used for cooking, most likely by heating stones in a fire and dropping them into a water-filled trough until the water boiled. Experiments have shown this works remarkably well. The sites date predominantly to the Bronze Age, roughly 1500 to 500 BC, though some have earlier or later phases of use. The crescent of shattered stone that accumulates around the trough is the physical residue of repeated heating and cooling, stones fracturing each time they are plunged into cold water. Some researchers have proposed alternative uses, including bathing, textile processing, or brewing, and the honest answer is that fulachtaí fia may have served different purposes in different places and periods. The Drummeen example sits within a county that has a dense concentration of prehistoric activity, from the limestone pavements of the Burren to the early field systems that survive beneath blanket bog elsewhere in Clare.