Espresso Machine Descaling Guide: Frequency, Descaling Agents, and Procedure

Volume I  ·  May 2026  ·  232 words

Mineral scale — primarily calcium carbonate — accumulates in the boiler, thermoblock, and water pathways of an espresso machine as water is heated and evaporates, leaving dissolved minerals behind. Scale reduces heating efficiency (the mineral layer insulates the heating element), restricts water flow through narrow passages, and, in severe cases, can block the thermosyphon loop in heat exchanger machines, causing overheating. Descaling dissolves the scale using an acid — citric acid, lactic acid, or a commercial descaler. The Dezcal descaler and Durgol Swiss Espresso Descaler are the standard products. Descaling frequency depends on water hardness: with soft water (<70 ppm as CaCO3), descale every 6-12 months; with hard water (>140 ppm), every 2-3 months. Using filtered water (carbon filtration for chlorine, not RO for minerals — RO water is so mineral-free that it can leach metals from the boiler) reduces scaling frequency but does not eliminate it. The descaling procedure involves running the descaling solution through the machine, allowing it to sit for 15-30 minutes to dissolve scale, and flushing thoroughly with fresh water — typically 2-3 tanks. Descale before the machine shows symptoms of scale buildup (longer heat-up time, reduced water flow, steam pressure loss), not after.