The Desert Water Bag

By Caleb Wilkerson

As we enter the heat of summer, the importance of having cool water available to drink cannot be overstated. While we drive our air-conditioned cars carrying coolers of ice and water on long summer trips, it is easy to take for granted our modern refrigeration technology. Back in the days of hood ornaments and before insulated coolers were common, folks had a surprising way of keeping their water cool during long, hot, summer drives. Canvas water bags, such as the one in the picture below, were used to hold water and keep it cool and refreshing. This particular bag was found hanging above the sink in the homestead’s Main Cabin kitchen.

  Ames Harris Neville Company Desert Water Bag, c. 1940

Ames Harris Neville Company Desert Water Bag, c. 1940

You may be wondering how canvas, a fabric, could be used to hold water. Not only did the canvas hold water, but it also enabled the water inside to remain cool. How did this work?

Canvas water bags cooled water through evaporation. As stated on the front of the bag, one must saturate the canvas before filling it with water. Doing this allows the water molecules to permeate the cloth fibers and utilize water surface tension to keep the water inside the bag from leaking. A little bit of leaching was actually what cooled the water inside the bag. When the water on the outside surface evaporated it pulled just a little bit through the canvas, and the evaporation process had a cooling effect on the water inside.

So what do cars have to do with water bags?

The water bags were hung from a car’s hood ornament and positioned in front of the grille in order to use the wind passing by the car to further cool the water. In most cases, this meant that the water in the bag, although not ice cold, was generally 25-30 degrees colder than the temperature outside. This would have been greatly refreshing during long, hot car trips.

No need for ice and a cooler, when you had a canvas bag and a car grille to hang it on!