Mayo is the secret to a non-soggy sandwich

Keeping a sandwich from getting soggy in a lunch box is mostly about building a moisture barrier — and mayo, butter, or cream cheese is the easiest one.

Most people blame the condiments. They’re not the problem. A generous spread of mayo (or butter, or cream cheese) smeared edge-to-edge on both slices actually seals the bread. The real culprits are wet ingredients: tomato, cucumber, pickles, lettuce. Those need to stay in the middle of the sandwich, not touching the bread, with cheese or meat acting as a buffer.

For genuinely wet stuff — tomato slices especially — the pro move is to pack them separately and assemble at lunchtime. Takes ten seconds and completely fixes the issue.

Two smaller tips: don’t wrap a sandwich while it’s still warm, because condensation steams the bread, and slightly toasted bread shrugs off moisture way better than soft white.

That spread of mayo is doing double duty as flavor and raincoat. Future-you at noon will appreciate it.