No Nestle Quik for Lunch

One time my daughter came home from school without her Dora thermos. She had mistakenly put someone else's Dora thermos in her backpack. When I went to wash it, I noticed inside was mugicha, which is a kind of barley tea. It seems like such an adult drink to me, unsweetened barley tea, but here it was, in a Dora thermos for a three-year-old. The preschool, like schools in Japan, tells us to only send water or "ocha" おちゃ (any kind of Japanese tea) for the kids to drink with their lunch each day. Absolutely nothing sweet. No juice, no sweet tea, etc.