Pesto is best when made fresh and then served, however for cooks on the run this is not always a feasible option. There are a variety of tips for freezing pesto, many of which are largely dependent upon the amount of pesto that will be frozen. As pesto should not be unfrozen and then refrozen, it is best to know exactly how much will be needed when it is defrosted and simply freeze in quantities of approximating that amount. As it is important for maintaining the integrity of the flavor of the pesto, it is best to freeze the pesto in a manner in which freezer burn is most effectively avoided.
There are those cooks that favor making large batches of the oil, basil, and pine nut sauce and then freezing pesto in ice cube trays. This allows for any size meal to be easily made in a short amount of time. Freezing pesto in ice cube trays will allow for any amount, from a few cubes to the whole tray, to be quickly defrosted and then heated up. To be sure to avoid freezer burn, once the pesto has frozen, seal the tray in a freezer-safe bag.
Similar to freezing pesto in ice cube trays is using muffin tins to freeze it in. When defrosted, this affords the cook single-serving size quantities of pesto. It is recommended that the muffin tin be sprayed with a cooking oil before spooning the fresh pesto into it. This will aid in easy removal from the tin when it comes time for defrosting the sauce. Again, it is suggested with this approach that the tin be sealed after the initial freezing of the pesto takes place.
Gallon freezer bags create an optimum storage container for freezing pesto in large quantities. When it is time to defrost the pesto, it can simply be set on the kitchen counter or in the sink in the freezer bag. The frozen pesto can then be allowed the time necessary to naturally come to room temperature.
Frozen pesto will remain good for approximately four to six months. After this time, it is best to discard it, as the flavor will no longer be optimal. Writing the date when the pesto is placed in the freezer, either on masking tape which can be placed on ice cube tray or muffin tin or with indelible marker on a freezer bag, will help ensure that the pesto is used before it goes bad.