Warm beverages are fine—in fact, many cyclists like to put warm tea in their Podium bottles for their early-morning rides. However, we don’t recommend putting boiling hot liquids in your bottle for two reasons:
With bottles like the eddy, you’ll essentially be drinking a hot beverage through a straw, which makes it hard to gauge the temperature and easy to burn your mouth.
Extra-hot or boiling water can distort the plastic.
Also, please keep in mind that the Kids’ eddy bottles do not work like baby bottles—so you shouldn’t boil the bottle itself to sterilize it (warm, soapy water or a run through the dishwasher should be enough to get it clean).