If you find yourself with more butter than you can use by the sell-by date, freezing some sticks is a good way to preserve it. Butter has a shelf life of about four months in the refrigerator, but if you freeze it successfully, you can use it over a long period of time with great results. As long as the butter you're freezing is fresh, it should keep well in the freezer. Salted butter will last about one year, while unsalted will stay fresh tasting for six months.
After a year, your frozen butter will still be safe to use, assuming it's remained frozen the entire time, but you might start to notice signs of freezer burn.
How to Freeze
Freezing butter is a simple process. If possible, keep the butter in its original box or container—that way, you'll have the package with the sell-by date or best-by date to refer to later, and you won't have to bother with labeling anything. Place boxes or sticks into storage bags before freezing.
If you don't have the original packaging, wrap the sticks of butter in aluminum foil or plastic wrap and then place inside a freezer bag. Alternatively, as cutting frozen butter can be challenging, slice the sticks into pieces that are 1 to 2 tablespoons, wrap well with plastic wrap or aluminum foil, and place in freezer bags.
Be sure to store the butter away from onions and other odiferous frozen foods as butter has a tendency to pick up the flavors and odors of the foods that are around it.
How to Use
Depending on the recipe, you might be able to use your butter while it's still frozen. If your recipe calls for melted butter, just take it straight from the freezer to the pan or microwave to melt it. You can also grate frozen butter using a cheese grater; cut the amount needed and grate over a piece of waxed paper or a cutting board. The small pieces will thaw quickly.
If you need to cream the butter, then it must be defrosted before use. The best way to do this is to place it in the refrigerator overnight. It will be difficult to cut a frozen stick of butter, so it is better to thaw a whole stick or pound at a time.
If you need butter right away, you can thaw it in the microwave by heating it for 10 seconds, flipping it to another side, and then heating it for another 10 seconds. Continue doing this, watching it closely, until the butter is soft but not melted.