We did a four-day camping trip in northern Michigan two summers ago. By day two, the cooler was a lukewarm pool of melted ice with floating cheese and soggy bread. We ate granola bars for dinner. My wife was not thrilled.

The next year I watched a bunch of YouTube videos about cooler packing — apparently there is a whole subculture of people who take this very seriously — and tried again. The difference was night and day. Ice was still solid on day three.

Pre-chill everything

Do not put warm drinks and room-temperature food into a cooler and expect ice to handle it. Refrigerate everything overnight before packing — drinks, fruit, condiments, even the bread if you have space. The ice is there to maintain cold, not create it from scratch. Starting cold means the ice lasts three times as long.

Layer properly

Put a solid inch of ice on the bottom. Then food that needs to stay coldest — raw meat, dairy, anything that would make you sick if it warmed up. Another layer of ice. Then drinks and snacks on top. The cold sinks, so the bottom stays coldest. If you put drinks on the bottom and meat on top, your chicken thighs are in the danger zone by lunch.

Block ice beats cubes

Freeze water in half-gallon milk jugs or Tupperware containers a few days before your trip. Block ice melts much more slowly than cubes because the surface-area-to-volume ratio is lower. One big block can outlast three bags of cubes. As a bonus, when it does melt, you have cold drinking water sealed in a jug instead of a swamp of mystery water at the bottom of the cooler.

Drain or don’t drain

Conventional wisdom says drain the water because it warms the remaining ice faster. But cold water is still cold — about 32°F — and it fills air gaps that would otherwise let warm air circulate every time you open the lid. I keep a small amount of water in the cooler and only drain it if there is so much that food is floating. For most trips, leaving the cold water in place works better.

We ate actual cooked meals on day three of that second trip. My wife was impressed. I am now the designated cooler-packer in our household forever.