Sibarist B3 FLAT vs Sibarist FLAT (FAST)

Fits

Flat basket

Flow

Medium · Manufacturer-stated

Material

Paper

Reuse

Single-use

Availability

Specialty only

How it brews

The B3 grade of Sibarist's abaca flat-bottom paper (associated with Matt Winton's flat-bed method), in S and M. Unlike the FAST papers, B3 is a lower-porosity sheet Sibarist rates as medium flow, trading some drainage speed for more body and retention across the flat bed. That medium class is the maker's own framing, not independently measured. It fits the flat-basket seat and interchanges with other flat papers of that fit; a pre-brew rinse is common.

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.