Toya Kohantei Hotel

A blended chloride spring drawn from the Toyako Spa Cooperative's pooled wells — Toya nos. 5, 6, 9, 12 mixed with community wells 1 through 7 — and led by sodium and calcium. The pooled source runs hot at around 50 °C with a generous 1,400 L/min flow, and the 2,890 mg/kg of dissolved residue puts it firmly in the richly mineralized band that leaves a thin mineral film on the skin. A notably high 178 mg/kg of metasilicic acid layers a silica-softness on top of the usual heat-retaining grip of a chloride bath, so the warmth lingers well after you step out.

北海道立衛生研究所