What's Happening?
A recent study conducted by a University of Copenhagen team, and published in the Journal of Food Science, indicates that bicarbonate levels in brewing water significantly influence coffee flavor, rather than the previously emphasized calcium and magnesium
hardness. Researchers brewed Colombian Kachalu coffee with ultrapure water, then introduced varying levels of calcium, magnesium, and bicarbonate. The study found that coffee brewed with 264 mg/L of calcium was indistinguishable from the ultrapure reference, and magnesium showed similar results. However, bicarbonate proved to be a critical factor. At 300 mg/L, perceived acidity in coffee dropped from 12.0 to 2.9 on a 15 cm scale, and fruitiness decreased from 10.2 to 2.4, while bitter and roasted notes intensified. The average brew pH also rose from 4.88 to 5.53, confirming bicarbonate's buffering effect on coffee acids. Even 120 mg/L of bicarbonate was detectable by tasters, suggesting its profound impact on the sensory profile of coffee.
Why It's Important?
This research is important for the U.S. coffee industry, particularly for baristas, roasters, and water-recipe companies, as it challenges long-held beliefs about optimal brewing water composition. The traditional focus on water hardness (calcium and magnesium) for flavor may be misplaced, with bicarbonate now identified as a primary determinant of a coffee's taste profile. This shift in understanding could lead to significant changes in how coffee professionals approach water treatment and mineral recipes. Companies that produce water filters and mineral additives for coffee brewing may need to re-evaluate their product formulations to prioritize bicarbonate management. For consumers, this could mean a more consistent and higher-quality coffee experience as cafes and home brewers adjust their practices based on these findings. The study suggests that prioritizing alkalinity testing and management could unlock new levels of flavor control and consistency in specialty coffee.
What's Next?
Coffee professionals are advised to prioritize testing alkalinity in their brewing water. The study's authors suggest that narrow hardness ranges might be more relevant for equipment protection than for flavor, prompting a re-evaluation of current water programs. While the study used one medium-roast coffee and did not measure extraction yield, indicating a need for further research across different roasts and origins, the findings provide a clear starting point. Filter manufacturers and water-recipe companies are now presented with a compelling reason to focus on bicarbonate. The industry can expect a greater emphasis on measuring and controlling bicarbonate levels to preserve the acidity and complexity that define specialty coffee. This could lead to new products and guidelines for water treatment in coffee preparation, ultimately enhancing the quality and consistency of coffee for consumers.
Beyond the Headlines
The deeper implication of this study lies in its potential to refine the scientific understanding of flavor chemistry in beverages. By isolating bicarbonate as a key variable, the research highlights the intricate interplay of chemical compounds in water and their profound effect on taste perception. This could inspire similar investigations into other beverages and food products where water quality is a critical, yet often oversimplified, factor. Ethically, this research encourages a more evidence-based approach within the culinary and beverage industries, moving beyond anecdotal beliefs to scientifically validated methods. Culturally, it could elevate the role of water science in coffee preparation, fostering a more sophisticated dialogue among enthusiasts and professionals about the nuances of taste. This development underscores a broader trend towards precision and scientific rigor in artisanal crafts, pushing the boundaries of what is considered 'perfect' in a cup of coffee.
