Bests & Worsts Reviews from Amazon

Several notions are being incorrectly perpetuated by many reviewers here with poor grasp of science. First of all, let me say that I own both this Takeya 40 oz thermos flask as well as a 40 oz Hydro Flask. These are comparable products with comparable build quality and performance in keeping fluids cool and delicious. In fact, I like the build quality on the small mouth cap of this more than the cap that comes standard with hydroflask. That alone is worth another $7 to $10. If you have a smaller mouth, you are going to appreciate drinking from this cap much more, trust me. Now, to debunk junk tests that people have been posting in their reviews. If you place 5 cubes of ice in a 40 oz container, then seal it and check on the ice 12 hours later, OF COURSE it is melted. Why? Because you sealed almost 40 oz of room temperature air into the container that the ice has now equilibrated with. If you FILL the container with ice or ice water and then check it 12 hours later, it will be closer to the same temp and structure inside the flask than if you had only partially filled it. The performance level is almost identical to the hydro flask brand but a little weaker since hydroflask has 30% more steel and is 5oz heavier (17oz to 12oz) as a result. As someone who finishes my drink within the workday period and not in 24 hours, I find that the performance is comparable to the Hydro Flask in this regard and that the less weight is actually a benefit. Second thing that is driving me nuts. Placing your flask in the fridge and finding that ice you left inside of it melted the next day does not show a technological failure but actually a SUCCESS. Once again, if you sealed room temperature air and some ice into the container, then place it in the fridge, the inside environment was so well sealed from the outside coolness of the fridge that the ice equilibrated to melt. Thermoses are not meant to "enhance" the cooling effect of a fridge. A thermos will only to slow down rate of reaching temperature equilibrium with the outside environment. In summary, if you want to get maximum performance of cooling retention from a thermo flask or hydro flask, try to FILL the container with cold or iced fluid at the beginning of your day. Technology only makes our lives easier when we actually understand how to utilize it. The Takeya Thermo Flask with small mouth spout that opens and closes with a single turn of the top is one of the best values I have found for this type of product.