Cupping Water

When professionals evaluate coffee, they use a standardized process known as cupping. Because coffee is roughly 98% to 99% water, the quality and mineral composition of the water used are just as critical as the quality of the green coffee itself. Cupping water must be clean, odorless, and free of chlorine or other chemical additives that could mask the delicate volatile aromatics of the sample.

The Specialty Coffee Association (SCA) provides specific guidelines for water quality in cupping. Ideally, the water should have a neutral pH and a specific mineral content—typically measured in parts per million (ppm)—to ensure that the acidity and sweetness of the coffee are properly extracted. If the water is too soft, the coffee may taste flat or overly acidic; if it is too hard, the coffee may taste chalky or muted.

In a professional setting, cupping water is heated to approximately 93°C (200°F). This temperature is chosen because it is hot enough to extract the necessary flavor compounds without scorching the grounds or causing the rapid degradation of delicate acids. The water is poured directly onto the grounds in the cupping bowl, where it remains in contact with the coffee for the duration of the evaluation.

For the home enthusiast, the lesson is clear: if your coffee tastes 'off' despite using high-quality beans, your water may be the culprit. Using filtered water that is balanced in minerals will allow you to taste the true character of the origin. When cupping, always use the same water source for every sample to ensure that your comparisons remain objective and consistent across the table.