While you may not like the texture of frozen milk after it has thawed, you can safely defrost any type of milk, according to the California Dairy Council. Skim or low-fat varieties of milk will fare better when defrosting due to the separation of the fat that occurs. Whole milk contains more fat, so the degree of separation of its components is greater.
Remove the frozen milk from the freezer within three months for best results.
Place the container of milk in the refrigerator to thaw. Leave it to thaw for approximately 24 hours.
Shake the milk before pouring to encourage the original texture. It will likely have a grainy texture after thawing due to separation.
Cold Water Thawing
Fill a sink or large container with cold water from the tap.
Submerge the container of frozen milk in the container of cold water to thaw.
Set a timer for 30 minutes. Allow the milk to thaw until the timer finishes. Press on the sides of the container to see if the frozen milk is breaking up and thawing. Drain or pour out the water and replace it with fresh cold water.
Reset the timer for another 30 minutes and check the milk when the timer finishes. If the milk has changed to mostly liquid form, shake it, pour out what you need and place the rest into the refrigerator. If not, change the water and set the timer for 30 minute intervals until the milk reaches a point where you can pour it. Shake and store in the refrigerator.