渋大湯（大湯と渋温泉総合源泉の混合泉）
Shibu O-yu (blend of O-yu and the Shibu Onsen combined source)Operated by · 渋温泉旅館組合
Mixed source
硫
Sulfate
+ Chloride
- Color
- almost colorless and transparent, with an iron and faintly salty taste
- Taste
- metallic iron taste with a faint saltiness
- Odor
- not recorded
Sodium-Calcium Sulfate spring
pH 5.7Weakly acidicHot source · 60°CHigh silica
Composition fingerprint1.2 g/kg dissolved · Hypotonic
Na⁺55
Ca²⁺35
SO₄²⁻51
◀ CationsAnions ▶
- Sodium Na⁺
- salt's cation — pairs with chloride to make the water salty.
- Sulfate SO₄²⁻
- "gypsum / Glauber's salt" — vessels and wound healing.
Known good for
- Aches & jointsstiff shoulders
- Circulationtired legs
- Warmingcold sensitivity
A blended source — Shibu O-yu, combining O-yu with the Shibu Onsen combined source — classified as a sodium-calcium sulfate-chloride spring. Sulfate gives the water a quiet body with a salty edge layered in, and it is moderately mineralized with noticeable presence. Weakly acidic, it carries a metallic iron taste with a faint saltiness. With 159 mg/kg of metasilicic acid, it leaves a thin silica film for noticeably smoother skin.
Sampled at bath inlet·Analyzed Nov 24, 2015·一般社団法人 上田薬剤師会 検査センター