Basil only grows in warm weather so it is necessary to store it for use during the winter. Fresh basil is always better but dried or frozen will do until the weather gets warmer and the herb can be planted again. Basil can be stored for about one year before it starts to lose flavor, and there are several methods to preserve it.
The most common method of preserving basil was to air-dry the leaves and then store them in bottles or jars for use in culinary dishes and for medicinal applications. Basil leaves were gathered in bundles and hung from rafters in the house or barn until they dried, but leaves did turn black. Physicians made infusions from fresh basil and added alcohol to them so they would keep for a few months. Basil was stored for the winter in salt, which preserved some of the flavor.
Some of the green color of basil can be retained by drying in the oven. Place leaves on a baking sheet and put it in the oven at the lowest temperature setting. Stir the leaves occasionally and remove from the oven when the leaves feel crispy, after about three to four hours. They can also be dried in a microwave at 50 percent power for two minutes between paper towels. If not crispy, microwave at 100 percent at one-minute intervals until they are. Microwave drying retains color the best.
Basil can be frozen, but when it thaws it tends to become limp. The taste will still be good. Do not wash basil before placing in freezer bags because the water will be retained and the leaves will become slimy. Wash it after thawing. Place half of a paper towel in the freezer bag with the basil and it will soak up some of the condensation and thawing liquid. Basil can be frozen in ice cube trays. Chop basil and put 2 tsp. in each compartment of the tray and fill with water. Once frozen, pop the cubes out and place in freezer bags. Most recipes call for 2 tsp. increments of basil, and this is perfect for soups or stews. Throw in the whole cube.
Basil stored in oil will last about one month at room temperature and three months in the refrigerator. Place ½ cup of olive oil in a pan and warm it up enough to be uncomfortable if touched but not burning hot. Add ½ cup chopped basil, stir it around, and let it sit until cool. Store the oil in a glass jar.
Containers for Storage
The best containers for basil are glass jars or bottles with tight-fitting lids. Jelly jars, glass salad dressing bottles, pickle jars or canning jars are suitable. Dark-colored jars work very well because the light does not affect the herb inside and the flavor will last longer. Plastic containers also work well for storing in the freezer or at room temperature. They must have air-tight lids. Freezer bags work well in the freezer.