Heat the warm water to 160º, in the kettle or what have you
13 oz warm water
While that's warming, gather your tools: the insulated water bottle and funnel, the chosaku (ladle), chasen (whisk), and the chawan (bowl)
Place the funnel over the top of the bottle
Get the cold water
With the chosaku, take 4 heaping scoops of matcha powder into the chawan
2 tsp ceremonial grade matcha powder
Wipe the chosaku clean
Pour about 1 to 2 tbsp of the cold water over the matcha powder.
3 oz ice cold water
Pour the rest of the cold water into the bottle. This will bring the final temperature down to drinking range (~135º) With the chasen, mix the powder and cold water well into a thin paste, until you can't see powder particles anymore.This keeps the powder from clumping, and from accidentally "burning" when adding the hot water. Sifting the powder is often recommended, but that shouldn't be needed with this method. Pour about half of the 160º warm water into the chawan. The temperature is important: lower and the powder doesn't mix well, higher and the tea gets "burned". Either way, it doesn't taste great. 13 oz warm water
With the chasen, vigorously whisk the tea, moving in a zig-zag motion across the bowl, for about a minute until tiny bubbles froth over most of the surface.This step is important to evenly bring the powder up from the bottom and suspend it in the solution; otherwise, it ends up collecting at the bottom of the bowl instead of in your stomach.If it doesn't froth, you probably didn't use enough powder, or used too much water. Pour the tea into the bottle
Wipe up any mess from that
Fill the bottle with the rest of the 160º warm water
Rinse the chasen, chawan, and funnel
Enjoy the tea -- should be at the perfect drinking temperature, and the insulated bottle will keep it there for a couple of hours.