Repost from www.hibiki-an.com.
Sen no Rikyu (1522 - 1591) who created the Japanese Tea Ceremony, unfortunately did not include a recipe for Iced Matcha in his teachings. It was invented later by an instructor of the traditional Tea Ceremony. But this instructor had to enjoy it by himself in secret because only hot Matcha was allowed in the formal Tea Ceremony. Fortunately today we do not need to be secretive about enjoying delicious Iced Matcha!
* Cool the Matcha bowl in the refrigerator in advance.
* Sift the matcha in order to prevent lumps, so the flavor and texture will be smooth and mellow.
* Pour 2 Chashaku of sifted Matcha into the Matcha bowl that has been cooled in advance.
* Pour 70ml of 0 Celsius temperature water into the Matcha bowl and whisk with the Chasen until the tea gets frothy. Matcha gets frothy when it is mixed with either cold 0 Celsius temperature or hot boiling water.