The B3 papers from Sibarist are a whole new paper material for coffee filtration - developed in collaboration with Matt Winton (WBrC 2021 Champion) for fast flow, yet a clean cup. The paper is thicker than most paper filters, but still has a high porosity and flow and makes a very tasty cup of coffee! It comes in 2 shapes, FLAT or HYBRID.
The B3 FLAT is a shape designed for any flat bottom brewers such as Kalita, April, Stagg X or Orea. When used with brewers like the Stagg X or the Orea, which have smooth walls, you're able to create very low bypass against the walls, and have an increased extraction. This works particularly well when paired with the BOOSTER 45 from Sibarist, which will enhance flow through the bed.
The B3 HYBRID is a shape designed for most Conical Brewers, such as the Hario V60, or the Origami as an example. The thicker paper allows the paper to sit off the ridges of the brewer without collapsing in, which enhances contact points, and highlights the effect of the brewer. It is folded into a 22mm flat base, which reduces the lower extracted coffee at the bottom of the cone brewer, turning it into a hybrid cone/flat brewer. This pairs perfectly with the BOOSTER 22 which will enhance flow through the base of the HYBRID filter.