These are the remnants of ancient cooking or processing sites, typically consisting of a mound of shattered stone that was heated in fire and dropped into a water-filled trough to bring it to the boil. Thousands have been recorded across Ireland, yet their precise function is still debated; some researchers argue for meat-boiling, others for brewing, bathing, or textile processing.

At Kilberrihert in north County Cork, a spread of this burnt material has been recorded in arable ground, the disturbed condition of the soil suggesting that ploughing has dispersed what may once have been a more recognisable mound. Notably, a second fulacht fia lies roughly a hundred metres to the east, which is not unusual; these sites often occur in loose clusters, possibly reflecting repeated use of a favoured location near a water source over many generations during the Bronze Age.