Ozark Trail Thermos Review: If you love hot coffee you need to read this

To test out the Ozark Trail Thermos line, I used the baseline temperature of 185 degrees Fahrenheit for all of the products I tested. My goal was to see how long I could keep a cup of coffee warm and if there would be variation in temperatures over time across the tumblers. I also used two of the 22oz Tumblers, one with the standard open mouth lid and one with a closed, spill proof lid.

I tested the temperature using a Weber meat thermometer which was $15 off the shelf. I used plain water which I boiled to temperature and placed inside each of the Tumblers and immediately closed with the provided lids.

I decided to do this test inside my house because exterior temperatures in Michigan were exceeding 90 degrees and I wanted to be able to keep a stable room temperature of 68 degrees Fahrenheit throughout the test.

I began with my initial 185 Degrees Fahrenheit temperature and tested each Tumbler 2 hours after placing the water inside, 4 hours after placing the water inside and 12 hours after placing the water inside.

Here are my results:

After 2 hours:

• 32oz – Tumbler
  • Temperature – 151.8 Degrees Fahrenheit
  • Heat loss – 33.2 Degrees Fahrenheit
• 24oz Water Bottle
  • Temperature – 154.7 Degrees Fahrenheit
  • Heat loss – 30.3 Degrees Fahrenheit
• 22oz Tumbler with locking lid
  • Temperature – 146.5 Degrees Fahrenheit
  • Heat loss – 38.5 Degrees Fahrenheit
• 22oz Tumbler with standard lid
  • Temperature – 145.2 Degrees Fahrenheit
  • Heat loss – 39.8 Degrees Fahrenheit
• 14oz Coffee mug
  • Temperature – 138.3 Degrees Fahrenheit
  • Heat loss – 46.7 Degrees Fahrenheit
• 10oz Lowball tumbler
  • Temperature – 131.4 Degrees Fahrenheit
  • Heat loss – 53.6 Degrees Fahrenheit

After 4 hours:

• 32oz – Tumbler
  • Temperature – 135.8 Degrees Fahrenheit
  • Heat loss – 49.2 Degrees Fahrenheit
• 24oz Water Bottle
  • Temperature – 143.4 Degrees Fahrenheit
  • Heat loss – 41.6 Degrees Fahrenheit
• 22oz Tumbler with locking lid
  • Temperature – 131.8 Degrees Fahrenheit
  • Heat loss – 53.2 Degrees Fahrenheit
• 22oz Tumbler with standard lid
  • Temperature – 128.6 Degrees Fahrenheit
  • Heat loss – 56.4 Degrees Fahrenheit
• 14oz Coffee mug
  • Temperature – 118.8 Degrees Fahrenheit
  • Heat loss – 66.2 Degrees Fahrenheit
• 10oz Lowball tumbler
  • Temperature – 111.9 Degrees Fahrenheit
  • Heat loss – 73.1 Degrees Fahrenheit

After 12 hours:

• 32oz – Tumbler
  • Temperature – 100.2 Degrees Fahrenheit
  • Heat loss – 84.8 Degrees Fahrenheit
• 24oz Water Bottle
  • Temperature – 111 Degrees Fahrenheit
  • Heat loss – 74 Degrees Fahrenheit
• 22oz Tumbler with locking lid
  • Temperature – 96.9 Degrees Fahrenheit
  • Heat loss – 88.1 Degrees Fahrenheit
• 22oz Tumbler with standard lid
  • Temperature – 93.6 Degrees Fahrenheit
  • Heat loss – 91.4 Degrees Fahrenheit
• 14oz Coffee mug
  • Temperature – 82.8 Degrees Fahrenheit
  • Heat loss – 102.2 Degrees Fahrenheit
• 10oz Lowball tumbler
  • Temperature – 80.8 Degrees Fahrenheit
  • Heat loss – 104.2 Degrees Fahrenheit

Overall I was pleased with the results of the Ozark Trail Thermoses I tested. A few of the key points that I think should be mentioned are listed below.

• There is a direct correlation between the size of the thermos and its ability to retain heat over time.
• The 24oz water bottle was the clear winner even though it was not the largest of the group. The screw on cap vs. the insulated lids appear to give the 24oz bottle an edge.
• There is very little difference in heat retention when using the provided lid vs. the additional locking lid, so the real benefit of the additional lid will be in keeping your beverage inside the mug.
• As a whole, each respective Tumbler has a specific application and will do a very good job at retaining heat when you are on the go.

One more very important thing to mention in the performance category is that when it comes to my personal acceptable temperatures to drink coffee, each of the Tumblers that I reviewed exceeded the performance numbers listed on the Walmart website.

If you are wondering what makes a double wall vacuum sealed thermos superior to other designs, we can help clear the air.

This design consists of, you guessed it, two stainless steel walls as well as a vacuum sealed chamber that sits in between the two walls. With a traditional single wall thermos, convection occurs transferring the internal heat out or vice versa, impacting the liquids temperature over time and at a greater pace.

The vacuum chamber in a double wall vacuum sealed thermos prevents that convection from occurring and greatly increases the duration that your drink remains at the desired temperature.

One of the things that I was curious about was how well the lids performed. The locking lid and open mouth lids do seem to provide similar results when paired with the 22oz Tumbler, but I had one more text I wanted to run.

Using a thermal imaging scope from ATN, I filled one of the 22oz mugs with water boiled to 185 degrees Fahrenheit and another filled with water boiled to 140 degrees Fahrenheit.

You can see in the image below that the thermos on the left has the hotter water, however the heat signature on both Tumblers is only present inside the Tumbler.

Once the lids are placed on to the Tumblers you can see a bit more in relation to how they work. With the locking lid, there appears to be more heat transference than the open mouth lid. Even with the locking lid absorbing more heat, it does provide a few degrees more heat retention over time.