La Marzocco continues to stress the importance of using appropriate water treatment to obtain both perfect espresso and to increase the lifespan of our machines.

With this message, we want to explain to you – in a very simple way – the rationale used as we defined the ranges suggested in our water calculator:

www.lamarzocco.com/water_calculator

NOTE: test your water by drawing samples from a faucet dispensing COLD water, which is NOT filtered or softened. Use a fresh sample for every test. Remember to TEST WATER IN EACH LOCATION: water is highly variable from location to location.

*** pH: concentration of H+ and OH- ions in a substance, telling how acidic or alkaline that substance is. The more acidic the solution, the lower the pH (higher concentration of H+ ions). The more alkaline the solution, the higher the pH (higher concentration of OH- ions). The pH of 7 is Neutral, which is an ideal value for water for a superior espresso brew.

When pH is higher than 8:

• Effects on espresso: over-extracted, sapid espressos, with low aroma, very low pleasant acidity and unpleasant bitter taste, low sweetness.
• Effects on equipment: if high pH is due to high salinity in combination with low hardness, corrosion phenomenon will quickly appear. If pH is due to high hardness, boiler will be prone to scale build-up.

When pH is lower than 6,5:

• Effects on espresso: unpleasant sour taste.
• Effects on equipment: greater concentration of H+ ions will increase the corrosive potential of the water against boilers and pipelines.

*** TDS: Total Dissolved Solids are the total content of organic and inorganic dissolved substances that may be found in a solution, like minerals, salts or metals dissolved in a given volume of water, expressed mg/L, also referred to as parts per million (ppm).

TDS higher than 150ppm:

• Effect on espresso: unbalanced body and acidity, low aromas, harsh taste.
• Effects on equipment: minerals build-up and slime into boilers.

TDS lower than 75ppm:

• Effects on espresso: weak body, tart taste.
• Effects on equipment: water becomes aggressive against espresso equipment’s materials and speed up corrosion phenomenon caused by other additional factors.

*** Total Hardness: the reflection of concentration of Ca2+ and Mg2+ ions PLUS other minerals in a solution. Hardness as measured by the La Marzocco test kit is expressed in parts per million (ppm), where one part per million is defined as one milligram calcium carbonate (CaCO3) per litre of water. Calcium Carbonate is the main constituent responsible for limescale build up.

Total Hardness higher that 150ppm:

• Effect on espresso: over-extraction, harsh and bitter taste.
• Effect on equipment: excessive limescale build-up.

Total Hardness lower than 90ppm:

• Effects on espresso: flat body, low aromatics, little or no crema, unpleasant acidity.
• Effects on equipment: water becomes aggressive and may cause/speed up corrosion in combination with other additional factors.

Total Iron: high iron content will give coffee (with added milk) a greenish tint and a bitter/metallic flavour. Water from the boilers may be rusty in colour.

*** Total Chloride: Chloride is an ion of chlorine. It occurs when chlorine gains an electron becoming Cl-. The most commonly known chloride is NaCl (SODIUM CHLORIDE) also known as TABLE SALT, which is very soluble in water. THIS IS COMMON IN COASTAL AREAS AND GROUND WATER SUPPLIES, CHLORIDES CAN ONLY BE REMOVED BY REVERSE OSMOSIS.

Chloride higher than 30ppm:

• Effects on espresso: increase the perception of sourness and enhance phenolic compounds and astringency.
• Effects on equipment: chlorides cause severe phenomenon of pitting corrosion.

*** Total Chlorine: Chlorine (Cl2) is a chemical element that is a very inexpensive, effective and readily available disinfectant used by municipalities to kill bacteria present in the water, thus preventing the spread of waterborne diseases. CAN BE REMOVED ONLY BY ACTIVE CARBON FILTERS.

• Effects on espresso: chlorine combines with coffee’s phenolic compounds causing a distinctive medicinal taste.
• Effects on equipment: chlorine increases corrosive potential of the water.

*** LSI index: LANGELIER SATURATION INDEX by keeping into consideration pH, hardness, alkalinity and water temperature, the Langelier formula determines whether the water will have a tendency to scale or corrode.

• LSI higher than 0.70: water will form mineral deposits.
• LSI lower than 0.10: water will be likely to dissolve minerals and attack metals.