"Aoimori's Natural Blue Apple Concentrate", which makes a "Royal Blue" drink just by dropping it in water, is available for pre-order at Village Vanguard Online. The price is 1,296 yen (tax included). The product will be shipped in early June.
This is a concentrate that changes color to royal blue when dropped in water with a dropper. The concentrate extracted from the flower called Anchan contains abundant pigment called anthocyanin, and it seems that the natural blue color spreads when it is put in water.
Even if you hang it on alcohol, wine, or alcohol. You can enjoy both hot and ice cream. If you put it in a drink containing acid such as lemon, the color will change to purple.