Yutomi no Sato Saigakukan On-yu Gensen
Analysis VerifiedThis is one of the private sources gushing in Yufuin Onsen, one of Japan's most popular hot spring resorts. The "On-yu" source is a simple hot spring drawn from within the property, known for being gentle and suitable for everyone due to its low mineral content. Its weak alkalinity of pH 8.2 gently removes dead skin cells, leaving the skin feeling smooth. Rich in metasilicic acid, a natural moisturizing component, it helps hydrate the skin after bathing. This spring is recommended for those seeking a gentle bath to unwind both body and soul while surrounded by the majestic nature of Mount Yufu.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
A trace component with gentle antibacterial and anti-inflammatory action.
Scores are calculated from mineral analysis data based on the Mineral Spring Analysis Guidelines (Ministry of Environment, Japan). They are unrelated to facility atmosphere or service quality.
▸Note
The temperature, pH and component values shown here are based on the hot spring analysis (source). Actual values in the bath may differ depending on heating, dilution, recycling and filtration. Please check current usage status at the facility.
With a gentle pH of 8.2, this weakly alkaline spring is suitable for long soaks. Immersing yourself slowly in the lukewarm water enhances relaxation. As it's rich in metasilicic acid, it's best to gently pat dry with a towel after bathing, without rinsing off the beneficial components.
The weakly alkaline nature of this spring, with a pH of 8.2, is traditionally associated with softening the skin's outer layer, which may support a silky skin feel. Furthermore, it contains a high concentration of metasilicic acid (95.8 mg/kg), a key indicator of "skin-beautifying" springs. This natural moisturizing agent creates a hydrating veil, helping to prevent dryness. It's an ideal choice for those seeking deep relaxation and rejuvenation.
While simple hot springs are gentle and suitable for most people, avoid bathing if you have any general contraindications for onsen (e.g., acute illness, severe heart conditions). If you have health concerns, please consult a medical professional.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Yutomi no Sato Saigakukan On-yu Gensen
- Spring type
- Simple Hot Spring
- Old spring type name
- 単純温泉
- Source temperature
- 44.9℃
- pH
- 8.2
- Flow type
- 動力揚湯
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2020-07-20
- Analyst organization
- 公益社団法人大分県薬剤師会
- Registration No.
- 大分県第3号
Cations
- Lithium ion Li⁺
- 0.20 mg/kg
- Sodium ion Na⁺
- 75.9 mg/kg
- Potassium ion K⁺
- 3.9 mg/kg
- Magnesium ion Mg²⁺
- 1.3 mg/kg
- Calcium ion Ca²⁺
- 7.1 mg/kg
- Total cations
- 0.09 mg/kg
Anions
- Fluoride ion F⁻
- 0.90 mg/kg
- Chloride ion Cl⁻
- 24.6 mg/kg
- Sulfate ion SO₄²⁻
- 12.8 mg/kg
- Bicarbonate ion HCO₃⁻
- 177 mg/kg
- Total anions
- 0.22 mg/kg
Undissociated Components
- Sulfuric acid H₂SO₄
- 0.00 mg/kg
- Phosphoric acid H₃PO₄
- 0.00 mg/kg
- Arsenious acid HAsO₂
- 0.00 mg/kg
- Metasilicic acid H₂SiO₃
- 95.8 mg/kg
- Metaboric acid HBO₂
- 1.5 mg/kg
- Total undissociated
- 0.10 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 3.5 mg/kg
- Total dissolved gas
- 0.00 mg/kg
Trace Components
- Radon Rn
- 0 Bq/kg
Totals
- Total dissolved substances
- 0.40 mg/kg
- Component total
- 0.41 mg/kg
- Evaporation residue
- 0.30 mg/kg
Usage
- Heating
- No
- Dilution
- No
- Recycle / Filter
- No
- Additives
- No
- Disinfection
- No
Indications & Contraindications
- Bathing indications
- Autonomic instability, Insomnia, Depression
- General indications
- High blood pressure (mild), Rheumatoid arthritis, Chronic pain or stiffness in muscles and joints, Muscle stiffness due to motor paralysis, Gastrointestinal dysfunction
- Contraindications
- Acute illness (especially with fever), Active tuberculosis, Malignant tumors, Severe heart disease, Respiratory failure, Renal failure, Bleeding disorders, Severe anemia, Any actively progressing illness, Pregnancy (especially early and late stages)
Drinking
- Drinkability
- Not drinkable
