The merits of “HAA for bath” stem from its ingredients and manufacturing methods. It takes about three months from the making of its ingredients to the completion of the bath powder.
The main ingredient is yunohana, or mineral deposit from hot springs, which has been made in Beppu from nearly 350 years ago. These crystals only react to the blue clay found in the mountains of Beppu. Yunohana are not made naturally and require gentle handling; artisans nurture these crystals for over 40 days in the summer and some 60-70 days in the winter.
After collection, the yunohana are stored in Beppu hot spring water for about a month to remove any impurities. Slowly, deliberately, the yunohana is refined into an amber essence and extracted.
The refined yunohana essence is acidic and too strong for the skin by itself; active components such as sodium sesquicarbonate and boric acid are added, and the mixture is left sitting for a day and a night.
This changes the acidity of the essence to slightly alkaline, making the quality of the resulting bathwater so gentle that even three-month-old babies can bathe in it.
“HAA for bath” is an extremely precious bath powder, the culmination of a three-month process starting from the manufacturing of yunohana and of artisans’ craft and studies.
Blue clay (Montmorillonite), the key ingredient
Blue clay (Montmorillonite) is the essential ingredient to yunohana making. Artisans spread this blue clay over the floor of the yunohana huts to create a clay bed. This blue clay, a specialty of the Beppu region, is comprised of very fine particles, and is a very unique ingredient rich in minerals such as iron an aluminum.