The formula for an Espresso “perfetto” starts with the water you use: temperature and quality of water are fundamental. Water comprises 98% of the average cup of coffee, so it’s not a stretch to think that water quality significantly impacts the final result.
Local tap water contains certain levels of calcium and magnesium, so water quality, or the liquid’s “hardness”, refers to its mineral level, which influences how the hot water and coffee interact; water that’s too hard or too soft can negatively impact the final cup. Many experts, including Andrej Godina, Coffee Expert and Authorized Trainer at the Specialty Coffee Association, suggest measuring water hardness and if necessary, inserting water softener. If using bottled water, opt for one with a fixed residue of about 200-300 mg/L. The ideal brewing water is not too sweet with balanced minerals that enhance the coffee’s natural flavours without overwhelming them.
In addition to the right hardness, the water temperature must remain stable throughout brewing since how the water penetrates the coffee dose is key to a perfectly balanced extraction. The perfect brewing temperature is between 83° and 92° Celsius. However, coffee connoisseurs believe keeping to the lower end of the scale releases the coffee’s more complex flavours.
Once the coffee and water are in place, pre-infusion and extraction occur. Pre-infusion involves ground coffee soaking gently in the filter before applying brewing pressure in order to ensure that water penetrates the grounds evenly once the extraction begins.
Extraction happens when pressurised hot water percolates through a layer of roasted, ground and compacted coffee and flows out from the filter spouts, extracting the characteristics of the coffee into the cup. It determines both the quality of the cup and the thickness of the crema, affecting the liquid’s fine, persistent texture.
Under-extraction occurs when the water flows too quickly, failing to capture the coffee grains’ substances. Yet, under-extraction isn’t tied solely to water flow; it can also be caused by old coffee, under-heated water, insufficient coffee grain dosage, or weak compacting. Under-extracted coffee is less full-bodied than the classic Espresso–the crema dissolves, the aromatics are weak, and the flavours are bland. Alternatively, overpacking the filter, too fine grinding and/or excessive compounding could lead to over-extraction. It results in a dark, exceptionally bitter liquid that emits an unpleasant aroma with a crema that tends to split in the centre and cling to the edge of the cup.
Par exemple, la technologie Active Temperature Control assure la température de préparation idéale en maintenant l’eau à une température stable pendant toute la préparation du café. Le Thermoblock hautement performant avec système de contrôle de la température garantit une température idéale stable en préparant un café.
La technologie Dynamic Preinfusion, figurant dans La Specialista Maestro et La Specialista Prestigio adapte la longueur du pilon d’infusion à la grosseur du café moulu, assurant que la surface entière du café entre uniformément en contact avec l’eau pour une extraction parfaite.
Que vous choisissiez une machine à café automatique ou une machine espresso broyeur, les amoureux du café qui préparent leur café à la maison peuvent, grâce à De’Longhi, savourer un espresso parfait dans leur propre maison. Et pour les personnes qui veulent lui donner une touche élégante, la mousse est la cinquième et dernière étape.
