From the manufacturer
De'Longhi EcoDeCalk Natural Descaler for Coffee Machines
Used regularly, the De'Longhi EcoDecalk machine descaler liquid significantly reduces the likelihood of premature breakdown from scale build-up, increases the energy efficiency, and improves the flavor and crema. Our descaler made with 100% lactic acid and is suitable for all espresso/coffee machines. The liquid is easier and quicker to use than coffee machine descaling tablets, and will keep your machine running smoothly so you can always enjoy your favorite beverages.