>>875207Fill 2-liter soda bottles half full of water. Put them in the freezer at an angle so that the water nearly touches the neck of the bottle. Freeze the water. When you go out and need to take water with you, fill the soda bottle all the way up with water. Insulated it inside your sleeping bag, blanket, or other such thing and it will stay ice cold nearly all day long.
>>875856>>875895I used an old winter wool sock for exactly that to keep drinks cool in the summer. You take a plastic container like an empty cottage cheese container and put the sock into it and fold over the excess on the outside. The really long wool socks are enough to fill the inside completely and cover the outside all the way down the side. Just about any glass, bottle, or can is able to fit snugly into the container. It works better than using those specially made drink coolers because it can accommodate many sizes and shapes.
Right now I'm using an old sun-bleached balaclava instead. Wool is best since condensation won't ruin its insulating effectiveness.
