I packed apple slices for my kid’s lunch for about a week before I noticed the pattern. Every single day, the container came back with half the slices brown and untouched. Not because my kid hates apples. Because they looked gross.

Brown apples are not rotten apples. That brown color is just oxygen reacting with the apple’s flesh, an enzyme called polyphenol oxidase doing its thing. Totally safe to eat. But try explaining that to a six-year-old.

The lemon juice trick everyone knows

Most people reach for lemon juice to stop the browning. It works because the acid slows down that enzyme. The problem is the taste. Lemon on apples is fine if you are making a tart, but for a plain lunchbox snack it makes everything taste faintly of lemon.

And my kid noticed. “Why does the apple taste like lemon?” was the exact quote that sent me looking for alternatives.

Salt water is the quiet winner

Here is the method I have used every school morning since. Fill a bowl with cold water and stir in about half a teaspoon of salt per cup of water. Soak the slices for three to five minutes, then drain and rinse them off.

The salt slows the browning just as well as lemon, and a quick rinse leaves almost no salty taste behind. You would never know the slices were treated.

The rinse matters, by the way. Skip it and the apple edges get a faint saltiness that is fine on a salad but weird in a snack box.

Other things that actually work

• Honey water: two tablespoons of honey in a cup of water, soak for a minute. A peptide in honey blocks the enzyme. It adds a touch of sweetness some kids love.
• Cold water alone: slows browning for an hour or two if you are eating soon.
• Rubber band trick: slice the apple, then reassemble it and wrap a rubber band around it so the cut sides stay pressed together. Looks odd, works fine.

What does not work

I tried keeping the slices in water in the lunchbox itself. That just made the box leak and the apples soggy. I also tried those plastic apple keepers, which work until your kid loses the top.

The salt water rinse is the one that stuck because it needs nothing special and costs nothing.