Reliable measurements of hydrophobicity of minerals and ores are important to the study of the separation performance of a froth flotation process. However, surface heterogeneity, which is inexorably linked to actual industrial ores, has always been a challenging factor to characterize with currently existing measurement techniques. In this study, a new apparatus of surface flotation that provides surface floatability and wettability evaluation requiring parsimonious needs in sample consumption is presented. It consists of a continuous‐flow macroscopically flat‐interface flotation cell for the selective separation at a moving liquid‐gas interface between hydrophobic mineral and hydrophilic gangue from scanty mineral samples. To prove the concept, comparative experiments were conducted with a mineral matrix composed of graphite and quartz using the new surface flotation apparatus, a micro‐flotation cell, and a Denver cell. The results obtained from the surface flotation cell indicate that its separation efficiency and its reproducibility are better than the two standard laboratory separation techniques. Use of this new technique provides more and better information related to the wettability of mineral/ore surfaces while requiring as low as 3 g of mineral samples.