共同噴気泉(なかの湯)
Kyodo Funkisen (Naka-no-yu)Sampled at wellhead
酸
Acidic
+ Sulfur
A simple acidic sulfur spring (hydrogen sulfide type) drawn from the communal steam vent 'Naka-no-yu' on the Maeguro slopes of Nasu-Shiobara. The wellhead runs at 79.2 °C — among Japan's hottest natural sources — and at pH 2.6 it is sharply acidic enough to sting slightly on contact. The water is colorless and clear at the source but carries a strong rotten-egg note of H₂S along with a sour, bitter taste; with 55.4 mg/kg of free hydrogen sulfide it has the unmistakable bite and skin feel of an acidic sulfur spring, long known for stubborn skin conditions.
pH
2.60
Acidic
Source temperature
79.2°C
Hot
Tonicity
0.41g/kg
Hypotonic
Free CO₂
55mg/kg
Low
Free H₂S
55mg/kg
Very high
- Color
- colorless and clear, with a strong hydrogen sulfide odor and a sour, bitter taste
- Taste
- sour and bitter
- Odor
- strong hydrogen sulfide
Highlights
- Ultra-acidic
- Sulfur-rich
- Top-decile hot
Analyzed Jul 20, 1993·栃木県郡部協会
