You can tell when a vendor has had some success at one of the many food expos during the year. It looks like sugar cane juicers hit it big.
There are three major areas where I check for street food trends, Insa-dong, Myeong-dong, and Hongdae. I first saw this in Hongdae last month, and I saw it again last weekend in Myeong-dong. Last year it looked to be fresh squeezed lemonade and, to a smaller extent, coconuts with straws stuck in them. Now we have vendors with stainless steel machines squeezing the juice out of sugar canes. When dunked in ice, they are surprisingly refreshing. Though I don’t see myself outright craving a cup.