My wife wonders how large my thermos collection is going to get. A lot larger, I think.
We test each thermos to determine how it performs with leaks, heat retention, ease of use, cleaning, etc.
Here’s the minimum you need

Lined  with stainless steel (not glass or plastic)
Wide mouth (a narrow mouth helps with heat retention, but makes [...]

An electric kettle is a perfect companion to thermos cooking at home. It boils water faster than any other method. Here are the results of our test of boiling 3 cups of water using various methods:

Electric Kettle: 3 minutes 23 seconds
Microwave: 6 minutes 20 seconds
Gas stove: 6 minutes 51 seconds

As you can see, you’ll be [...]