HE-134
Freezing Vegetables at Home
William D. Evers and April C. Mason Foods and Nutrition Extension Specialists
Freezing is one of the simplest and least time-consuming ways to preserve many vegetables. And frozen vegetables are convenient to use. They are ready to serve on short notice because most of the pre-table preparation is done before freezing.
Many vegetables can be frozen satisfactorily. However, the quality of the frozen product varies with the kind of packaging, quality of vegetable, stage of maturity, type of pre-freezing treatment, and rate of freezing. If you have doubts about how well a vegetable will freeze, test-freeze three or four packages, using the directions given in this publication. Sample the food after freezing. This test shows only the effect of the freezing process. To test the effect of storage, you would need to leave the packages frozen for a longer period of time. Try a week and then a month of storage to see if the quality of the vegetable is acceptable to you.
Selecting the Right Freezing Container
Much of the success of home freezing depends on choosing the right freezer container or wrap. If vegetables are not properly packaged when they are put in the freezer, they will lose moisture, color, and nutritional value and develop an off-flavor. For example, the evaporation of ice crystals can produce freezer-burn, a dry, grainy, discolored area, which makes food unattractive and unappetizing. The use of proper freezing containers and packaging methods controls or prevents freezer burn.
Glass, metal, and rigid plastic containers that are made especially for freezing are excellent packaging selections because they effectively control evaporation. Bags, wrapping materials, and waxed cartons made for freezing are also sufficiently moisture-vapor-resistant. But ordinary waxed papers and paper cartons from 
purchased dairy products are not durable or moisture-vapor-resistant enough to be suitable for freezer packaging.
All containers used for freezing should be leakproof and easy to seal. Packaging materials must be durable and must not become brittle enough to crack at low temperatures.
Preparing Vegetables for Freezing
Fresh, tender vegetables right from the garden are best for freezing. The fresher the vegetable, the better the frozen product!
Washing is the first step in preparing vegetables for freezing. Wash vegetables thoroughly in several changes of cold water. Lift them completely out of the water with each change of water so grit can settle to the bottom of the pan and be discarded following each washing.
Peel, trim, and prepare the vegetables according to the directions for each specific vegetable given in Table 1. Unless vegetables are to be cut into uniformly-sized pieces, they should be sorted according to size.
Blanching or Heating Before Packing
An important step in preparing most vegetables for freezing is heating, also called “blanching.” When a vegetable is picked, the enzymes responsible for the changes during growth and ripening continue to be active. This can lead to off-flavors, discoloration, and texture changes in the picked vegetable. Heating vegetables stops this enzyme activity. If a vegetable is not heated prior to freezing, enzyme activity will continue even at freezer temperatures.
In addition, heating wilts or softens vegetables and makes them easier to pack. It also kills microorganisms, brightens the color, and helps retain nutritional value during freezing. The
Purdue University Cooperative Extension Service, West Lafayette, IN 47907