(Editor's Note: This article was originally published on August 31, 2007. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
(A continuation of Part I)
In the early 1900s a man was on an expedition to Labrador with the U.S Geographic Service. He noticed that caribou meat exposed to cold air still tasted fresh after many weeks.
When he returned to the U.S. he developed a quick freeze machine. It consisted of a garbage can containing a layer of steel pipes filled with a refrigerant of sodium chloride brine. Food was placed between the pipes and frozen to a temperature of -40 degrees F and kept well for weeks.
Shortly thereafter he started his frozen food business selling fish.
The man's name was Clarence Birdseye and the company bearing his name is still in business today. Freezing foods to preserve them is more popular today than ever.
Home freezing generally doesn’t take as much time as canning, and as a personal preference, some foods just taste better frozen than canned. For example, I think corn and asparagus taste much better frozen than canned.
How Freezing Works
Freezing to 0 degrees F or below preserves foods by preventing the growth of microorganisms that cause spoilage. Note that I said preventing growth, not killing the microorganisms. Once thawed, frozen foods need to be treated like any other perishable product: cooked immediately or refrigerated.
Choose only fresh firm fruits or vegetables. Make sure they are free of soft spots and bruises. Wash thoroughly in cold water taking care to keep them out of the grit that falls to the bottom of the sink..
Blanching (Scalding in boiling water)
Almost all fruits and vegetables require blanching before freezing. Blanching stops or slows the actions of enzymes that cause spoilage; it also retains flavor, texture and color.
Blanching times are very important and they vary due to types and size of fruits and vegetables. Once the blanching time is complete the produce is plunged into ice water to stop the action.
There are several ways in which you can pack your fruits or vegetables.
Dry Pack: after blanching and draining, foods are packed into containers and placed into the freezer.
Tray Pack: again after blanching and draining foods are placed onto a tray (like a cookie sheet) and placed into the freezer. Once frozen, the food is placed into containers and put back into the freezer. This method prevents the contents from freezing into a solid block and makes it easier to remove a portion at time for use. This method works well with berries and cut green beans.
Syrup Pack: many folks like to freeze fruits such as peaches and pears in syrup made from sugar and water. The syrup is brought to a boil and poured over the fruits before freezing.
Containers for freezing
You have several choices when selecting freezer containers. The types of containers are governed by type and size of product being frozen and personal preferences. The containers need to be moisture and vapor resistant, durable and easy to seal.
Freezer/Canning Jars. Reusable, reseal able. Wide mouth jars are easier to empty than regular moth canning jars.
Plastic Freezer containers. Made especially for freezing. Available in a variety of sizes. Reseal able, reusable.
Freezer Bags inexpensive, a variety of sizes. Great for irregular sizes like corn on the cob. Not reusable.
Containers not to use: ice cream, milk containers. Not vapor resistant, food might pick up odors or tastes from other items on freezer.
Foods that do not freeze well.
Certain foods just do not freeze well. They tend to get mushy and soft. Foods that do not freeze well include rhubarb, cabbage, celery, onions, melons, cucumbers, garlic, green peppers, lettuce and radishes.
How long is frozen food good? The USDA states that frozen foods are safe to eat indefinitely if kept at 0 degrees F or below. For quality sake frozen fruits and vegetables should be consumed within 10-12 months.
Odds and Ends.
As stated earlier the temperature in the freezer needs to be at 0 degrees or below to keep foods frozen for extended periods of time. Most freezer compartments in your refrigerate are not that cold. Use a deep freezer to keeps foods frozen for more than a few weeks.
Many light colored fruits such as peaches, pears etc tend to discolor when exposed to air. To prevent this there are several products that you can use to prevent this. These products contain vitamin C (ascorbic acid) which prevents oxidation. Follow instructions on the package.
If you have a power failure DO NOT OPEN THE DOOR to the freezer. Most foods will stay frozen for 2-3 days.
Be sure to label and date each container that you place into the freezer.