Start by placing bulkier items you won't need until you picnic?think more durable foods like a block of cheese, fancy dip, or smoked salmon. Then add a layer of ice. Above that base, in what's known as the ?core? of the pack, layer in the heaviest items, like beer, wine, and/or cider. Then more ice.

Yes, you can put ice directly into a backpack cooler, but in 2026, the strategy has evolved for better performance. For high-end brands like Yeti or RTIC, the liners are waterproof and leakproof, making them safe for loose ice. However, to maximize "ice retention" (how long the cold lasts), experts suggest pre-chilling the cooler with a "sacrificial" bag of ice overnight. Use a 2:1 ice-to-contents ratio—twice as much ice as food. For best results, use a mix: block ice (which melts slowly) at the bottom and cubed ice to fill air pockets. To keep your gear light, many hikers in 2026 prefer frozen water bottles; they act as ice blocks initially and provide cold drinking water as they thaw, preventing the "soggy sandwich" issue that occurs when loose ice melts into a pool of water at the bottom.