Developed in Japan during the Heian period; the ridged interior design appears to have evolved independently from Chinese and Korean mortars which are typically smooth; the distinctive kushime ridges are a uniquely Japanese contribution to grinding technology
The suribachi is a ceramic mortar with an interior covered in radiating ridges (kushime) that dramatically increase grinding surface area — fundamentally different from smooth Western mortars which require impact-crushing rather than friction-grinding. The surikogi is a wooden pestle (traditionally wood from the sansho pepper tree, which transfers a subtle bittersweet aroma). The ridged interior grinds wet and dry ingredients into pastes and powders through rotary friction rather than pounding: sesame seeds (goma-ae base), miso (smoothing lumps), sanshō (dried pepper), tofu (smooth white filling), and dried fish (for furikake) are all ground in suribachi. The ridge pattern is characteristically Japanese: radiating lines from centre to edge, which trap ingredient and prevent slippage during grinding. Care: rinse immediately after use before residue dries in ridges; a toothbrush-like brush (tawashi) cleans ridges; never use abrasive scouring which would blunt the ridges.
Friction grinding rather than impact releases oils gradually without overheating — hot-grinding from impact mortar destroys volatile aromatic compounds in sesame and sanshō
Ridged interior enables friction grinding (not impact); rotary motion with pestle pressed into bowl; wet ingredients bind dry; surikogi wooden material prevents chipping and adds subtle aroma; grinding direction is consistent rotation not random.
Toast sesame first for maximum flavour release; add ingredients in small amounts — overloading prevents grinding contact with ridges; a few drops of mirin or soy added mid-grind helps sesame paste form; the suribachi can be used as a serving bowl — warmth from hands during communal sesame paste preparation is traditional at Buddhist temples for shojin cooking.
Impact pounding (cracks the ridges); using a smooth mortar for Japanese preparations — different grinding physics; adding all liquid at once to dry seed grinding; grinding hot ingredients that steam and crack ceramic.
Tsuji, Shizuo — Japanese Cooking: A Simple Art; Hachisu, Nancy Singleton — Japanese Farm Food