flat dripper (part 1)
( from instagram post 2025.2.14 )
< flat vs conical : part 1 >
I have little experience in flat bottom drippers, far less than conical ones. The reason can be traced back to an old coffee rumor that "flat dripper gives lower acidity and richer body than a conical". I have been a believer for many years until recently found out it was unlikely true (more details in part 2).
A main difference between flats and conicals is the shape of coffee beds they form. While a conical forms a conical bed, a flat bottom forms a wide and shallow puck. It has some advantages over conical shape:
More contact area with fresh water (except for large doses) - efficient extraction
Less bed depth - good extraction evenness from top to bottom layers
However, shallow bed is not without caveat as it can be broken by strong water stream. As a stream strikes through the bed and reaches the filter, it creates an easy path for water to escape aka channeling.
Therefore, flat dripper generally works better in large doses. Besides, slow pouring or tool-assisted pouring (e.g. melodrip) can minimize agitation thus less channeling risk. In comparison, conical benefits more from agitation as the bed center is the deepest. For conicals, you may consider pouring in small circles and avoid hitting the edge of coffee bed.
Another difference is the wall angle. Despite variations among brands, the walls of flats in general are more vertical than conicals. More verticality means less water can escape through filter and bypass extraction. One who desires minimal bypass can set filter paper in a way that makes full contact with the wall. A filter shaping tool can get the job done without hassle.
Yet these differences are not the cause to the "low acidity, heavy body" impression of flat drippers. Let's stay tuned for part 2 and share your thoughts!
