DeLonghi descaler, marketed as DeLonghi EcoDecalk Descaler as of 2015, is a liquid used for removing limescale from inside coffee machines. The descaler is biodegradable and includes plant lactic acid as a reactive agent. It replaces the discontinued product Entkalker Descaler.
Limescale is a build up of impurities left behind by water usage. It can accumulate in large patches in the interior of coffee machines, affecting the taste of the brewed coffee. The build-up on the elements also means it takes more energy to brew a pot of coffee.
While cleaning the outside components of a coffee machine just takes elbow grease, a descaler is used to deep clean the inner workings. The descaling solution is run through the system by brewing it along with a pot of water. The lactic acid, or citric acid depending on the brand, reacts with the lime scale and dissolves it.
A treatment once every six months is usually enough to protect the coffee maker, unless hard water is used for coffee making. Hard water has more dissolved minerals, causing the lime scale deposits to build up faster. Coffeemakers that get heavy usage, such as in coffee shops, should also get more frequent descaling treatments.