How do I adjust grind for different brew times?

The relationship between grind size and brew time is the fundamental lever of coffee extraction. When you grind your coffee, you are determining how much surface area is exposed to the water. A finer grind exposes more surface area, which allows for faster extraction but also creates more resistance to water flow. A coarser grind exposes less surface area, which slows down extraction but allows water to pass through more easily.

If you are using a method like a V60 or a drip machine, your brew time is a direct indicator of how well your grind size matches your recipe. If your coffee is finishing too quickly, the water is likely 'channeling' through the grounds without extracting enough flavor, resulting in a thin, sour cup. By adjusting your grind to be finer, you increase the resistance, forcing the water to spend more time in contact with the coffee, which helps pull out the sweetness and balance.

Conversely, if your brew is taking too long, the water is likely over-extracting the coffee, pulling out harsh, bitter compounds that mask the delicate notes of the bean. In this case, moving to a coarser grind will allow the water to flow more freely, reducing the contact time and bringing the extraction back into the 'sweet spot.'

In practice, making these adjustments requires patience. Change your grind size in small, incremental steps—don't jump from 'fine' to 'coarse' all at once. Keep your other variables, like water temperature and dose, constant while you dial in the grind. By focusing on one variable at a time, you will learn how your specific grinder and beans respond to changes, eventually allowing you to hit your target brew time and flavor profile with consistency every single morning.