Any appliance that uses water can eventually develop mineral scale and build-up, including espresso coffee machines for home and office use. This mineral build-up is particularly likely in areas with hard water, but it can occur in any espresso maker in just about any location. Over time, mineral scale can result in poor water flavour and quality, and can even affect the machine function. Use citric acid to clean the espresso maker and help preserve the flavour and quality of the coffee.
Dissolve 5 ml (1 tsp) of citric acid powder in 250 ml (1 cup) of hot water. Mix well until the citric acid is dissolved and then add cold water until the total liquid volume is approximately 1 litre (4 cups).
Open the lid on top of the espresso machine and fill the water tank with the citric acid mixture. Close the lid.
Run 295 ml (10 fl oz) of water through the steam wand on the espresso machine and 85 ml (3 fl oz) through the brew head. Turn the espresso machine off.
Wait 20 minutes and run another 295 ml (10 fl oz) of water through the steam wand and 85 ml (3 fl oz) through the brew head.
Repeat until the water tank is empty. Fill the tank with clean, cold water and run the water through the machine. Run some water through the brew head and steam wand as well. Refill the tank with water and repeat until the water has no citric smell or taste.
Buy citric acid powder from hardware shops, supermarkets and online cleaning equipment suppliers.
Use caution when using citric acid powder, as it may cause harm to eyes. Wash hands after handling.