To keep your liquids hotter for longer, we recommend pre-heating your bottle by pouring boiling water in first and then your beverage. Yes, just like a good barista will do for a cold mug. This means that the initial water is used to heat the bottle rather than your beverage. The same goes for cold; if you really need it to stay cold for a long time, let some ice water sit in your bottle for a few minutes, pour it out, and then use your insulated bottle for your beverage.