1. Pure Water & Sea Salt (Udon & Knife-Cut Wheat)
Dissolving 2% to 4% sea salt into water before mixing tightens the gluten matrix by shielding electrical charges on protein strands, allowing them to pack closer together. In Sanuki udon from Kagawa Prefecture, saline levels climb up to 12% in summer, creating a firm, leathery dough that can only be flattened by treading on it inside thick vinyl sheets.
Hand feel: Cool, dense, and slightly rubbery before resting; turns remarkably supple and glossy after a 2-hour rest.