Extra summer tomatoes can be quickly frozen without blanching whether their skins are on or off, whether they are whole, sliced, chopped or pureed.
First, be sure to select firm, ripe tomatoes to freeze. Discard any tomatoes that are spoiled.
Like all produce, tomatoes need to be properly washed before freezing. Wet tomatoes with water, rub the surfaces, rinse them with running water and dry them with a paper towel. Do not wash tomatoes in a sink filled with water because contaminated water can be absorbed through tomatoes' stem scars. Using soap or detergent is not recommended with fruits and vegetables because they can absorb detergent residues.
Peel the washed tomatoes by dipping them into boiling water for about one minute, or until the skin splits. The skin can then be easily removed. To freeze tomatoes with their skins, wash the tomatoes and then cut away their stem scars and the surrounding areas.
Wait to season tomatoes until after they have been defrosted and are about to be served. Freezing could possibly weaken or strengthen herbs and seasonings.
For freezing tomatoes, with or without skins, place them on a cookie sheet and freeze them. Once the tomatoes are frozen, transfer them to bags or containers.
For best results, use containers meant for freezing and make sure they are tightly sealed. Use a freezer with a temperature at or below zero degrees Fahrenheit. It is recommended that all frozen vegetables be eaten within eight months.
To use the frozen tomatoes, remove them and run them under warm water in a sink. This will help defrost them and any tomato skins will slip off easily.
Thawed tomatoes can be used in recipes calling for cooked tomatoes. However, freezing gives tomatoes a mushy texture, so do not substitute them for raw tomatoes.
For more information on freezing tomatoes and food safety, visit UNL Extension's Food: Nutrition, Safety & Cooking, http://lancaster.unl.edu/food/ciq.shtml.