Food Preservation for Self-Reliance – Dehydrating and Freezing
By Roxanne Bare, owner of Terra Mater
As promised, albeit a month late, here is the bonus article for the series on food preservation. Even with five articles there are two more methods of preserving foods that I have not been able to squeeze in. This article will discuss dehydrating and freezing foods.
Throughout the world, primitive civilizations dehydrated plants, berries, roots, meat and fish by putting them in the sun to dry. The Phoenicians dried fish in open air, the Chinese dried tea leaves, and the ancient Egyptians dried grains which were found in tombs by archeologists. Native American tribes preserved fruits, vegetables, and meats for winter months and showed the early settlers how to do so. By 1795, the French had developed the first dehydrator designed to regulate drying conditions.
While drying is easy and the food takes up less space, it will never replace canning and freezing because these methods retain the taste, appearance and nutritive value better than dehydration. However, dehydrated foods are an efficient and healthy choice to add variety to meals and snacks.
There are a few different methods of drying foods that include sun drying, oven drying, and a mechanical dehydrator. In Illinois, conditions are rarely favorable for sun drying. Temperatures need to be high with low humidity. In our fair state, when temperatures are about 95° the humidity is usually at 86% or higher, therefore, not good for sun drying. Electric dehydrators are easy to obtain and are very efficient and easy to use.
Before placing in a dehydrator, most fruits and vegetables need to be pretreated to stop enzyme action that causes the breakdown of cellular tissue in the food. Depending on the food, this may be steam blanching, treating with lemon juice or some other acid, or sulfuring. Some fruits and vegetables are not very friendly to dehydrating because they have such high moisture content that by the time you dry that out, there is really nothing left. Lettuce, cucumbers and melons come to mind.
Herbs are easily dried without pretreatment. I do dry a lot of my own herbs but I can usually do them by air drying them in a well ventilated area. The trick is waiting for low humidity days.
A favorite in our house is making dried meat, also known as jerky. For this I always use an electric dehydrator so I am assured of sufficient heat and even air flow to keep a safe food product.
An excellent source of further information on drying foods is available at http://www.aces.uiuc.edu/vista/html_pubs/DRYING/dryfood.html. This is the online version of the same circular I have on my food preservation resource shelf at home.The final method of food preservation that I wish to discuss is freezing foods. The best thing about freezing food is that it is the method that best preserves the nutritional content of fresh foods. Other benefits are the ability to do small amounts, it generally is less time consuming and there is no need for special equipment. On the down side, a major power outage can leave you with a bunch of thawed food that must either be eaten promptly or thrown away.
Freezing does not kill microorganisms that can cause food borne illness but it will stop them from growing or multiplying. So as long as your food was clean and safe before placing in the freezer, there is little danger of a problem upon thawing and immediate use.
Vegetables generally need to be pre-treated by water or steam blanching before freezing. This requires a few minutes in a steamer basket over boiling water or a few minutes covered with boiling water, then quick chilling in cold water. Blanching will preserve color, flavor and nutritive value. After the food is chilled you just strain off the excess water and put the food into your bags or containers, close them up and place in the freezer. For a step by step photo essay of freezing broccoli from my garden you can visit my personal blog at http://musingsbyroxie.blogspot.com/2012/06/freezing-broccoli.html
Fruits are generally packed in a syrup pack, a sugar pack or an unsweetened pack. Most fruit has better texture and flavor when packed with at least a light syrup. I have found that berries are an excellent fruit to freeze without any sugar though. For those, I place them in a single layer on a waxed paper covered cookie sheet. Let freeze solid then pack them into bags. Many fruits will darken during freezing especially if not packed in liquid. To help reduce this you may wish to ad ascorbic acid to the fruit during preparation. Most fruits will freeze well but the texture will be softer than a fresh product.
It is important to discuss food safety regarding frozen foods. When thawing foods to cook, one should not leave the package out on the counter to thaw. Foods should be thawed in the refrigerator. If you are planning to use fruits they can be kept cold until serving. Vegetables and meats also need to be kept cold until cooking. Sometimes you can even keep the foods frozen until putting them directly into the pan for cooking. Generally you will want to have meats thawed out before cooking to assure even heating and thorough cooking.
In the case of a power outage or a broken freezer, you may find yourself with accidentally thawed foods. Two factors determine what happens now: time and temperature. How warm did the food get and how long was it in the temperature danger zone. If the food still contains ice crystals, it is usually safe for cooking or refreezing. Keep in mind that refreezing will probably lose some quality of the food and that the storage time should be limited. If there are no ice crystals in the food but the temperature stayed below 40°F, you should plan to cook the food as you would if you had never frozen it. If the temperature of the food went above 40°F for even a couple of hours, you should discard the food. Some bacteria may double in numbers every 15 to 20 minutes in warmer temperatures.
An excellent booklet on freezing foods can be found at http://www.ag.ndsu.edu/pubs/yf/foods/fn403.pdf. This booklet covers all the basics of preparing foods for the freezer and food safety guidelines.
This wraps up my series of articles on food preservation. Gardens are in full production right now so happy harvest and preserving!