Iron-rich hot springs are unique baths that range from reddish-brown to yellowish-brown. The experience of soaking in water that resembles the color of tea is unlike any other hot spring. These springs are relatively rare in Japan, so if you find one, be sure to take a dip.

What is an Iron-Rich Hot Spring?

An iron-rich hot spring refers to a hot spring that contains a certain amount of iron ions. If the total iron ions in 1kg of hot spring water exceed 20mg, it is classified as an iron-rich hot spring.

Depending on the type of iron ions, they can be further categorized into types such as "Iron(II) Bicarbonate Spring" and "Iron(II) Sulfate Spring."

Appearance and Characteristics

Color: Reddish-brown to yellowish-brown
Smell: Metallic odor
Texture: Normal
pH: Neutral to slightly acidic

The most notable feature is its color. The reddish-brown water resembles tea.

Why Does It Turn Reddish-Brown?

The interesting aspect of iron-rich hot springs is that they are transparent when they first emerge.

Freshly emerged iron-rich hot spring water is clear, with dissolved iron ions. However, upon exposure to air, the iron ions oxidize and turn into iron rust. This iron rust is what gives the water its reddish-brown color.

In other words, the reddish-brown color is evidence of a "fresh iron-rich hot spring."

Witnessing the Color Change

Some facilities allow you to witness the process of the spring water changing from transparent to reddish-brown. Watching this transformation is quite an intriguing experience.

A chemical reaction is happening right before your eyes, allowing you to truly feel the "living hot spring."

Health Benefits of Iron

Iron-rich hot springs are abundant in iron. However, absorption of iron through bathing is limited.

For those seeking the health benefits of iron, drinking the spring water (known as "drinking hot springs") is considered effective. Consuming the water allows the iron to be absorbed into the body, potentially aiding in the improvement of anemia.

Main Benefits

Common indications for iron-rich hot springs:

• Anemia (drinking hot springs)
• Menopausal disorders
• Neuralgia, muscle pain, joint pain
• Cold sensitivity, peripheral circulatory disorders
• Chronic digestive disorders
• Chronic skin diseases

In addition to the circulation-boosting effects of bathing, drinking the spring water may help improve anemia.

Notable Iron-Rich Hot Springs

Kin no Yu at Arima Onsen (Hyogo Prefecture): A famous reddish-brown hot spring rich in iron and salt.

Naruko Onsen (Miyagi Prefecture): A hot spring area offering a variety of spring qualities, including iron-rich springs.

Kawayu Onsen (Wakayama Prefecture): A unique hot spring area where digging into the riverbank reveals hot spring water.

Recommended For

Those who wish to experience reddish-brown hot springs, individuals prone to anemia, and those looking to enjoy unique hot springs. Iron-rich hot springs offer a visually enjoyable experience.

Effects of Drinking Hot Springs

Iron-rich springs are one of the spring qualities suitable for drinking.

Consuming iron can help improve anemia. However, always follow the instructions of the facility when drinking hot spring water, as not all hot springs are suitable for consumption.

Additionally, excessive iron intake can lead to constipation, so be cautious not to overconsume.

Bathing Precautions

Iron-rich hot springs may cause iron rust to adhere to bathtubs and washbasins.

This is an inherent characteristic of the hot spring. Although facilities clean regularly, consider any slight rust as proof of a "genuine iron-rich hot spring" and enjoy it.

Also, white clothing may become stained reddish-brown. It is recommended to use towels provided by the facility or bring dark-colored towels.

Conclusion

Iron-rich hot springs are a relatively rare spring quality in Japan. The reddish-brown to yellowish-brown colored water is visually delightful.

The water is transparent when it first emerges and turns reddish-brown upon exposure to air. Witnessing this chemical reaction firsthand is part of the charm of iron-rich hot springs. Drinking the spring water is also said to help improve anemia. If you find a rare iron-rich hot spring, be sure to experience it.