The size of old-fashioned galvanized steel milk cans proves both an advantage and disadvantage. On one hand, you can store a large quantity of milk; on the other, you must have a large refrigerator in which to store the can of milk. Other things to consider before storing milk in a galvanized can include the can's quality, your milk usage and your transportation method.
Galvanized-steel milk cans come in 3-gallon to 100-gallon sizes. Any can larger than 3 gallons won't fit in a regular refrigerator, making a commercial-grade cooler a must for proper storage. Milk must stay under 40 degrees Fahrenheit to prevent bacterial growth, making proper transportation critical; you need the milk delivered to you in a refrigerated truck from the supplier.
Milk usage also comes into play when storing large quantities of milk. Milk lasts about two weeks under ideal storage conditions, so you want to keep just enough as you think you will use. You don't, however, have to fill the container full each time you add a fresh batch of milk, so if you have the storage space, a high-volume can won't be a problem.
Never store milk in an old-fashioned galvanized can that shows signs of corrosion or rusting. Although galvanized steel doesn't rust quickly, it does eventually. Also, if the milk can you have was used for storing non-food items, you can't use it to store milk. Clean and sanitize the can before you add milk to it and after each time you empty it.