The Hydro Flask Standard Mouth isn’t the cheapest thermos we tested. But it comes with a lifetime warranty and scored well enough in our heat and cold retention tests to make it the best overall value for a basic thermos.
The Hydro Flask is made with stainless steel with double insulated walls and a smooth outercoat that helps you keep a firm grip on it. Condensation doesn’t collect on the outside and the outside walls don’t feel too warm or cool when it is filled with hot or cold drinks. It isn’t a good choice for commuting because the lid is a screw cap that may take more than one hand to open. Plus, it has a wide, over-the-nose mouth that makes it hard to control how fast your drink pours from it. But it can work well for a day trip of hiking, fishing or picnicking. Hydro Flask does sell other caps and lids that work with this thermos to make it easier to take on the go.
This thermos holds 18 ounces of liquid and will keep it hot for 12 hours, or cold for 24 hours. During our heat tests this Hydro Flask cooled down 76 degrees; it also warmed up 29 degrees during cold retention tests. This is one of the biggest temperature changes we saw during testing, but our drinks were still hot enough to enjoy, and cold drinks were cooler than room temperature. If you’d prefer a thermos that insulates liquids for longer, check out our review of the Thermos Sipp.
This thermos is completely BPA free and is hand wash only, even the lid. The screw top lid is secure. We bounced, tossed, jostled, tipped and shook this thermos and it didn’t leak at all. It has a rubber-feeling handle to help you carry the Hydro Flask around, but it isn’t strong enough to slip around a belt or rope while hiking.
The Hydro Flask Standard Mouth thermos is a good value because it comes with a lifetime warranty and keeps the outer flask at room temperature even when the thermos contains hot or cold liquids. It also prevents condensation from collecting on the outside. It keeps drinks hot for 12 hours, but it won’t be as hot as other thermoses we tested since the Hydro Flask had an average 76-degree temperature change during our tests.