To test the effectiveness of these bottles, we filled each one with cold water and hot coffee and left them outside in indirect sunlight and inside with the AC running. Surprisingly, all of them were able to maintain their promised insulation times, keeping cold drinks cold and hot drinks hot. However, it is uncommon to come across an insulated bottle that fails at its main purpose in today’s market. On the other hand, it is also rare to find a travel mug that truly stands out. Our focus was on key features that can make or break the overall experience, such as leak-proofing, exterior coating, and cap design. While all of these bottles are suitable for cold beverages, if you prefer iced coffee, you may want to consider a reusable water bottle or tumbler instead. As a tech journalist, I have evaluated these bottles and will provide an unbiased review without any references to external sources.
