The Milk(y) Way

Sage likes to have a glass of milk every couple of days. Hands down, this has been one of our greatest challenges: keeping milk cold. Without access to electricity, our refrigerator will not work. Our cooler keeps things cold enough for a few days, but there are other issues. I started with a plastic half-gallon container. About half of it soured because I don't drink the stuff and David only does with cookies. We haven't been eating many of those, either. I scaled back to smaller packaging, but mostly they are paper-based, and become waterlogged as the ice melts and everything dives into the icy soup. Quickly the paper breaks down, creating a milky frothy mess in the cooler. Then I tried individual sizes in plastic containers. Worked great, except the caps are not water-tight. No matter what, the milk spills or spoils. Not green...or economical. Powdered milk, you're up. Dazzle me.