Moreno Faina explains how water, roasting, and extraction change the flavor of coffee

He is one of the world's leading coffee experts. He directs the Università del Caffè at Illycaffe, an institution that trains professionals from around the world in the world of coffee, and in this interview he reviews the keys to understanding and improving its flavor.

Water is a crucial factor, especially in espresso, because its chemical composition can alter percolation time and expand the coffee grounds. Ions such as calcium, magnesium, and bicarbonate affect the flavor, while chlorine and organic compounds should be avoided. There is no universally accepted ideal water, although a total hardness of 50 to 170 mg/L of CaCO3, an alkalinity of between 40 and 80 mg/L, and a pH between 6 and 8 are recommended.

Coffee is versatile in both sweet and savory recipes. 100% Arabica blends pair well with milk, white chocolate, or butter, and enhance caramel or roasted notes. Single-origin coffees, such as Ethiopian Arabica, can display floral notes that complement ingredients like bergamot or bitter orange. Brazilian Arabica, sweeter and more caramelized, lends itself to brewing methods like the French press and pairs well with dark chocolate.

Tasting coffee at home is an excellent way to train your palate. You evaluate visual aspects (color, texture, creaminess), taste (bitter, acidic, sweet), and olfactory aspects, both orthonasal and retronasal. Identifying aromas involves connecting with previous sensory memories. Although it can be challenging at first, training your taste and smell allows you to distinguish the qualities of coffee over time.

During extraction, compounds are released in stages: first the acids (bright), then the sugars (sweet), and finally the bitters, which can be unpleasant if over-extraction occurs. The coffee-to-water ratio, grind size, temperature, pressure, and dosage must be adjusted according to the brewing method. Bitterness comes from caffeine and roasting: over-roasting, poor bean quality, or incorrectly calibrated parameters can lead to unwanted bitterness. Balance is achieved by carefully managing the entire process.

Cold brew coffee, originating in Japan, extracts compounds at low temperatures for 12 hours. The result is a less acidic coffee with a light body and mild aromas. Although the caffeine is fully extracted, its sensory profile differs from that of hot brewing methods.

The technical difference between preparing coffee at home and in a coffee shop lies in the precise control of variables such as grind, dosage, pressure, and water. However, with good raw materials, well-maintained equipment, and experience, home brewing results can rival those of professionals.

During roasting, reactions such as the Maillard reaction occur, generating aromatic compounds. The type of roast influences the final profile, but it must be adapted to the home roasting method, the available equipment, and the characteristics of the bean. Freshness preserves the oils and aromatic compounds, so once roasted, coffee must be protected from oxygen and moisture. Pressurization techniques, such as those used by Illy, extend its shelf life to between 24 and 36 months and maintain its sensory quality.