Does brewing time change the taste?

The common misconception is that brewing time is an independent variable that 'changes' flavor in a vacuum. In reality, time is a proxy for extraction yield—the percentage of the coffee bean's mass that ends up in your cup. As water remains in contact with grounds, it follows a predictable sequence: acids and salts dissolve first, followed by sugars, and finally, heavier, bitter-tasting plant fibers and tannins. If you cut the time short, you risk a sour, thin cup; leave it too long, and you invite astringency and bitterness. For the producer, this is a critical distinction. A high-quality, high-altitude bean with complex acidity requires precise extraction to showcase its terroir. If a brewer uses an incorrect time, they aren't just 'changing the taste'—they are obscuring the specific post-harvest processing and varietal characteristics that the farmer spent months cultivating. Recent research, including studies from the UC Davis Coffee Center, clarifies that time, temperature, and grind size are interdependent. They do not intrinsically alter the coffee's chemical potential; rather, they dictate the efficiency with which you access that potential. When you adjust your brew time, you are essentially managing the 'solubility budget' of the coffee bed. The goal is not to find a 'perfect' time, but to find the duration that balances the specific solubility of that roast level and grind size to achieve a target Total Dissolved Solids (TDS) and extraction yield that honors the bean's origin.