Can a coffee grinder adjust the coarseness of coffee by controlling the grinding time?

Some types of coffee grinders (especially blade type) can indirectly adjust the thickness of coffee powder by controlling the grinding time, but there are also certain limitations. The following is a point by point introduction:

1. Blade type grinder: controlling the thickness through time
▸Principle: The blade rotates at high speed to chop coffee beans, and the longer the grinding time, the finer the particles.
▸Short time (a few seconds): The powder is coarse and suitable for pressing or cold extraction;
▸Medium time (8-15 seconds): Medium thickness, suitable for American drip filtration or hand flushing;
▸Long term (over 20 seconds): The powder is fine and suitable for mocha pots or espresso;
▸Disadvantage: The particles are uneven, and there is a phenomenon of "powder+fragments" coexisting, which affects the extraction equilibrium.

2. Grinding disc grinder: adjustable by scale, not by time
▸Principle: Control the thickness by adjusting the distance between the grinding discs, rather than relying on grinding time.
▸After setting the coarse and fine gears, even if the grinding time is different, the particle thickness remains consistent;
▸Advantages: The particles are more uniform, suitable for Italian and hand punching methods that require precise control;
▸Conclusion: It is not recommended to control the thickness of the grinding disc by grinding time, and the built-in adjustment function should be used.

3. Grinding time mainly affects the total amount and should not be overly dependent
▸Even for blade type models, a long grinding time does not necessarily mean uniform grinding;
▸Excessive grinding can produce "fine dust", leading to over extraction and a bitter taste in coffee;
▸Suggest combining powder screening or observing powder status to avoid relying solely on time for judgment.

4. It is recommended to use the coarse and fine adjustment function instead of time control (if available)
▸If the grinder has a coarse and fine scale adjustment function, this method should be prioritized for more precise control;
▸Time control can only be used as a "suboptimal solution" for models without adjustment functions.