I thought I put this on our blog before, but I can't find it. This is a great family home evening project.
Heat pint jars (without bands) in a 250 degree oven for 20 minutes. (A dripper pan works well for this.) One pound of butter slightly more than fills one pint jar, so if you melt 11 pounds of butter, heat 12 pint jars. While the jars are heating, melt the butter slowly (in a large kettle) until it comes to a slow boil. Using a large spatula, stir the bottom of the pot often to prevent scorching. Reduce heat and simmer for 5 minutes. Place the jar lids in a small pot and bring to a boil, leaving to simmer until needed.
Stirring the melted butter from the bottom to the top with a ladle or measuring cup with spout and handle, pour the melted butter carefully into heated jars through a canning jar funnel. Leave a 3/4" of head space in the jar.
Wipe the tops of jars, then place on hot lids and screw on the bands tightly. Lids will seal as the jars cool. The butter will separate into three layers: foam, oil and milk solids. Once the lids "pop" and seal, shake the jars to mix your butter. Do this every 15 minutes or so, until the butter retains more consistency throughout the jar. (This may take up to an hour or longer.) When just slightly warm, move jars to the refrigerator. Check and shake every 10 minutes until they are hardened in the jar. Then leave them in the refrigerator for an hour.
Canned butter should store for 3 years or longer on a cool dark shelf. It could replace the butter-flavor shortening requirement on the basic food storage amounts list, or simply included as a topping or flavoring.
Note: It does not need to be refrigerated once opened, if used within a reasonable amount of time.