Get a real food thermos, not a Tupperware

A real food thermos is the only way to pack soup or stew without leaking in your bag. Regular plastic containers with snap lids are not made for liquids, and they will fail you eventually.

Get a wide-mouth stainless steel food jar, not a narrow thermos meant for coffee. The wide opening makes it easier to eat from, and the screw-on lid with a silicone gasket is what keeps the liquid in. Brands like Thermos, Stanley, and Zojirushi make solid ones. Before trusting it, test it at home: fill with water, close it, shake it upside down over the sink.

Preheat the thermos before you add soup. Fill it with boiling water, close it, let it sit for five minutes, then dump it out and pour in your hot soup. That keeps your lunch hot enough to enjoy and also warms the seal, which helps it grip better. Make sure nothing is stuck on the threads or the gasket, then tighten until it stops. Don’t overtighten with a death grip — just firm.

One extra layer of insurance: put the sealed thermos in a gallon zip bag before it goes in your backpack. It costs nothing and catches anything if the lid fails. Also, carry it upright — most thermos designs work best when the liquid isn’t pushing against the lid from the side. If your bag forces it sideways, an insulated bottle sleeve that holds it vertically will save you a mess.

Thermos and stew are a match made in heaven. Just don’t test your luck with a Snapware from the kitchen cupboard.