Have you ever tried the real onsen?
1. Continuous flow from source (Gensen kakenagashi) Whilst heat might be added, there is no water added to this type of bath. With this kind of system, the high temperatures at the source are made more moderate and suitable for bathing by the use of heat-exchange devices either at the point where the water enters the bath, or in the bath itself.The hot spring of a ‘Gensen kakenageshi’ bath is always released without being used in a circulation system.
2. Continuous flow (Kakenagashi) In order to maintain the moderate temperature of this type of bath, both water and heat are added to the water supply. Like the ‘Gensen’ varient of ‘Kakenagashi’ – once the water enters the bath, it is released and does not go through a circulation system.
3. Direct flow from source – heated and circulation bath system the hot spring supply is untouched as it enters the bath from the entry point, but in order to keep the water at a suitable temperature, a circulation system is used.
4. Direct flow from source – heated, filtered, sterilised, and circulation system.
The hot spring supply is untreated as it enters the bath from the entry point, but in order to keep the water at a suitable temperature, a circulation system is used to heat the water, whilst also purifying and sterilizing it.
5. Hot spring supply is heated, filtered and sterilised before entering the bath.
As soon as the hot spring is supplied to the bath, in order to keep the water at a consistent volume and temperature, the water is first circulated, during which time it is also purified and sterilised before once more being released into the bath to be used.
Even if the hot spring has a temperature of 25 degrees, the overall mineral composition within 1kg water adds up to less than 1000mg. The level of stimulation is low, but there will potentially be a wide range of effects when used.
Carbon Dioxide Onsen
Carbon Dioxide Onsen
It is where in 1kg of hot spring water, there is 100mg or more of released carbonic acid. This causes carbon dioxide to dissolve, creating a fine froth on the surface, and it is often referred to as a ‘bubbly spa’ or ‘soda spa’. The onsen has the effect of expanding blood vessels, helping to lower blood pressure.
Sodium Bicarbonate Saline Onsen
This type of onsen is alkaline, and there are two different types: Sodium Bicarbonate and Bicarbonate Earth Onsen. It is a clear colour and has the ability to make skin feel smooth, and in particular sodium bicarbonate makes skin soft and gentle, while removing dirt, often being called ‘the water of beautiful skin’.
Containing salt similar to the kinds found in sea water, the salt has the effect of controlling perspiration after bathing, also means that the body’s ability to retain heat is also excellent. This type of onsen is known as ‘Fever water’.
The spring water, with a bitter taste when drunk, has been known as ‘Water for cuts and bruises’. Sulphate onsen are divided into three categories: Calcium sulphate, Sodium sulphate, containing traces of natrium, and a regular bitter spring which contains traces of magnesium.
Ferruginous Onsen (Iron)
There are two types of Ferruginous Onsen: Carbonated Iron Onsen, and Melanterite Onsen. The water is a colourless, transparent as it gushes up, but as it comes into contact with the atmosphere, it develops into a dark reddish-brown colour and weakens the waters effect. This type of spring helps the body’s ability to retain heat, and when drunk replenishes the body’s iron levels.
Colourless and transparent, or a yellowish-brown colour with a bitter taste, these acidic springs have strong sterilising properties.
Cupriferous/Ferruginous Onsen (Copper and Iron)
Similar to the Ferruginous spring, the water oxides with the atmosphere once exposed, becoming an opaque yellow colour, and leaving a red-brown sediment. Because there are traces of iron in the spring, the temperature can be very hot, but this kind of onsen is not very effective for cleaning the body.
With the distinctive and unique smell of bad eggs, this kind of spring has the ability to expand the blood vessels in the body. Because the hydrogen sulphide in the spring is toxic, proper ventilation is essential. The pale-yellow sediment are known as ‘Hot water flowers’. The sulphur can soften the hardened keratin of the skin, and is also good for acne and spots.
This type of spring has powerful sterilising properties, and a strong stimulation that permeates the skin. Acidic Onsen are not recommended for people with sensitive skin or weak health.
Only tiny amounts of radioactive minerals are found in this type of hot spring, and it can also be referred to as a ‘Radium Onsen’ or ‘Radon Onsen’. Strong evidence has been recorded that shows the miniscule amounts of radioactivity in the water have a beneficial effect on the body.