Sibarist FLAT (FAST) vs April Flat Bottom Paper

Fits

Flat basket

Flow

Fast · Manufacturer-stated

Material

Paper · Abaca

Reuse

Single-use

Availability

Specialty only

How it brews

The flat-bottom sibling of the FAST cone: a smooth, non-fluted paper using the same abaca technology, sized S (≈Kalita 155) and M (≈Kalita 185) for wave-style flat drippers, plus a larger size for basket machines. Because the wall is smooth rather than pleated, Sibarist markets it as keeping water in even contact with the whole bed and reducing bypass while still draining fast — a mechanism claim from the maker, not a measured result. It drops into a Kalita Wave 155/185 seat, so it's an option anywhere those papers fit. Single-use, made in Barcelona.

Fits

Flat basket, Kalita Wave 155, Kalita Wave 185

Flow

Fast · Manufacturer-stated

Material

Paper · Cellulose

Reuse

Single-use

Availability

Specialty only

How it brews

The Copenhagen roastery's own flat-bottom paper, sold Small (≈Kalita 155 / Origami S) and Large (size 175, for the April plastic brewer). It's cut to sit deep with a wide base and is marketed as flowing faster than conventional flat papers — that speed claim is April's, kept as a class rather than a number here. One honest ambiguity: older retailer copy described April filters as using Sibarist's abaca FAST technology, while the current listing says virgin wood pulp (cellulose); we record cellulose per the direct listing but don't treat abaca as confirmed. It drops into a Kalita Wave 155/185 seat, so it interchanges with those papers.