湯畑（草津温泉）
Yubatake Source (Kusatsu Onsen)Operated by · 大阪屋旅館
酸
Acidic
+ 含硫黄泉 · Sulfate · Chloride
Hot source · 54°CUltra-acidicHigh silicaSulfur-rich
Known good for
- Skin conditionsatopic skin, eczema
- Circulationtired legs
- Aches & jointsstiff shoulders
- Sensitive-skin cautionbroken or dry skin
Fed by Kusatsu's Yubatake source, this is strongly acidic water at pH 2.0 — sharp enough to prickle on contact. The posted name reads acidic, sulfur-bearing aluminium-sulfate-chloride: free hydrogen sulfide at 13 mg/kg carries the characteristic rotten-egg note, while aluminium and sulfate give the water a firm, astringent body across roughly 1.7 g/kg of dissolved minerals. Metasilicic acid runs high at 230 mg/kg, leaving the thin silica film that smooths skin after such a sharp bath. The usage panel states no heating, no recirculation and no disinfection — water is diluted only when the incoming flow is too hot after the daily cleaning.
Analyzed May 2, 2003·社団法人 群馬県薬剤師会·Cert no. 群馬薬第2号