What is the difference between a cold brew and iced coffee?

The distinction between cold brew and iced coffee is a matter of extraction kinetics. Brewing is a process of dissolving soluble compounds—caffeine, acids, lipids, and sugars—from the coffee matrix into water. Hot water (typically 91–96°C) acts as a high-energy solvent, rapidly breaking down these compounds to produce the bright, complex, and acidic profiles characteristic of specialty coffee. Because many floral and fruity volatile compounds are heat-sensitive, they are effectively captured only through hot brewing.

Cold brew, by contrast, relies on time to compensate for the lack of thermal energy. By steeping coarse grounds in cold water for 12 to 24 hours, the extraction is limited. Crucially, this low-temperature environment is less efficient at dissolving bitter chlorogenic acid lactones and certain organic acids. For the producer, this means cold brew can mask the nuanced terroir of a high-quality bean, often flattening the vibrant acidity that a farmer worked to preserve during processing. While cold brew is often marketed as 'stronger' due to higher caffeine concentrations—a result of high coffee-to-water ratios—it is chemically less complex than a properly brewed hot coffee. A common misconception is that cold brew is inherently 'better' for sensitive stomachs; while it is less acidic, the primary difference is simply a lack of the bright, volatile aromatics that define the bean's origin. Iced coffee, particularly when brewed using the Japanese method (brewing hot directly onto ice), preserves these delicate aromatics, offering a more faithful representation of the producer's harvest.