Whats better – flat-base or convex-base tampers?
This is one of the age-old questions in the world of tamping. The whole purpose of tamping is to get uniform compression throughout the coffee puck, and in my opinion this can only be achieved if the tamper has a flat base. A convex tamper will create a dished tamp, rather than a flat one. This extra pressure at the centre will discourage even water flow throughout the coffee, and thus will lead to uneven extraction. Flat base tampers also sit nicely on the bench, rather than rolling around and scuffing the centre of the tamper. However others have counter-arguments. Some suggest convex tampers improve ‘particle distribution’ (that is, how evenly the coffee grounds are distributed in the filter basket). Most grinders tend to heap a pile of coffee grounds in the middle of the filter basket, and the convex shape of the tamper is intended to push this pile to the sides of the basket and leave a perfect tamp. While this may have its merits, a convex tamper still results in the centre being
