In the heat of the summer it can be tricky to keep food cool. If you don’t want to drag around a cooler with you here is a trick to keep the food at the right temperature on a summer picnic or hike.
The night before, take two plastic bottles and fill them with 4/5 parts of water – beware that water expands when freezing! Put them in the freezer without the cork and let the water freeze to ice.
In the morning you screw the corks shut and use them to cool the food in your backpack. The ice will slowly melt during the day providing you with perfectly cool drinking water too!