In our two-part series on food preservation basics, we talk about methods, which include the ingredients discussed in our ‘Spin, “Food Preservation, Let’s Talk Ingredients.” Make sure you read that as well; it’s just as important to understand the food preservation ingredients at your disposal as it is important to understand methods.
This is an overview of all of the traditional food preservation methods that are available to the homeowner. People can be surprised when they learn about all of the available methods and how they work. It’s beneficial to know the landscape before planning how you’re going to preserve surplus food.
Most people don’t immediately associate food and burial, but it just goes to show you that assumptions don’t get you anywhere useful in life. The constant temperatures, darkness, and humidity levels associated with burial are ideal for preventing spoilage of root crops in particular, but also foods like onions and cabbages and foods that have been previously dried. The root cellar, a wonderful way to preserve root vegetables and other hardy vegetables such as cabbages, is one form of burial.
Other forms of burial storage include the storage clamp and the cache pit. Storage clamps recreate the conditions found in a root cellar where top soil is scraped to create a shallow, rectangular depression, food such as potatoes are piled into a ridge-shaped heap, then covered with about six inches of straw or hay. On top of this is placed the soil that was removed during scraping.
The cache pit, used by agricultural Native American tribes such as the Mandan and Hidatsa, is a combination of a root cellar and a storage clamp that was used for winter food storage. Pits were dug into the ground to store the important crops of corn, beans, sunflower seeds, and dried squash.
Burial has been used in conjunction with fermentation, and was common in the making of kimchi and sauerkraut. Desiccation (drying) has also been associated with burial in desert locales, such as in Egypt. In fact, drying was first used in ancient Egypt as a food preservation method after it was noticed that burial of food caused it to be dried and, therefore, preserved. Ultimately this method included mummification of humans and not just food.
Candying fruits, also known as Glacé or crystallized fruit, involves placing whole or pieces of fruit in a heated syrup, then draining it, and repeating this cycle using increasingly strong concentrations of syrup over weeks or even months. It is the intense saturation of the fruit in sugar that enhances desiccation and creates an environment unfavorable for bacterial growth. Plus, it’s tasty!
Canning is probably the best known method of home food preservation using glass jars (or metal cans) with pressure-sealed lids, and includes processing by water bath or pressure canner. The water bath method of canning can be used with foods such as high-sugar jams and jellies or acidic tomato products and pickles. Water bath canning is accessible to most homeowners who have the desire to dip their toe in food preservation methods. Canning a fruit jam is a recommended first step for the soul who is interested in stepping into the world of home food preservation.
Pressure canning of foods is needed for non-acid foods including many vegetables like beans and potatoes, and meats. A pressure canner (as opposed to a pressure cooker) is required for canning these items, and it is recommended that someone have some water-bath canning experience under their belt before purchasing and using a pressure canner. But the versatility a pressure canner brings to the home storage kitchen is worth its weight in gold.
Curing involves using salt (sometimes in combination with sugar) to preserve meats and fish. Curing is one popular way to make sure meat is available in winter for the home larder. Salt at different concentrations inhibits the growth of dangerous food bacteria such as Listeria, Staphylococcus, and Salmonella.
Salt can be added to meats as a liquid brine (strong enough to float an egg), or as a dry cure, such as with sausage making. Dry salting is also known as corning, because in early British history Anglo Saxons preserved meats with “corns” (coarse pieces) of salt. Irish corned beef is the most famous example of this, but any meat can be corned in this way for preservation.
Nitrites can also be used in meat curing because they allow meats to retain a pink color, and they help to prevent the growth of bacteria such as botulism. However, nitrite use can be tricky business as it is toxic at high enough levels. For a review of nitrites in curing, read “Nitrite in Meat” from the University of Minnesota Extension office. (Note: nitrates are no longer allowed for commercial meat curing, with the exception of dry-cured, uncooked meats. It is a suspected carcinogen.)
But not all salt curing can prevent the growth of bacteria; because of this it is recommended that home meat curers start out their curing adventures by using pre-made mixes, which have been tested for food safety. Potential sources for ready-made curing mixes include sites like Morton Salt, or Wedliny Domowe, which includes a cure-calculator on their website so you know exactly how much of a cure mix you need for different meats. But there are other sources for cures, and you’re encouraged to seek out trusted sources.
There are several ways to dry food, and drying food is arguably the most efficient, and oldest, method to preserve food. It is not uncommon to find dried fruits and vegetables in Egyptian tombs that are thousands of years old, and still edible. Dehydrating food removes enough moisture to prevent decay. The secret to good drying include heating the food so the moisture is eliminated quickly enough to not affect food flavor, but not so hot that it cooks the food. But getting the heat to the right point is important; if the temperature is too low bacteria can grow, yet if it’s too high the food may harden on the surface before the inside has had a chance to dry. Air circulation is also paramount when it comes to properly drying foods.
Dried food can come in many forms — from fruit leathers to jerky — and they all can be dried using the power of the sun, electric dehydrators, or the oven. But all methods must have good air circulation to carry the moisture away from your food. If you live in a drier climate, the sun may be all you need to dry foods. You can dry food outside on racks covered with screening to protect from insects and birds, or build a solar dehydrator like the one provided in this great article from Home Power Magazine, “Indirect, Through-Pass, Solar Food Dryer.”
If solar dehydration won’t work for you, you can always purchase an electric food dehydrator. Electric food dehydrators can cost anywhere between $20 and $190, but I’ve used $30 models with great success in the past. You can also use your oven to dehydrate foods, though this method can be tricky as ovens can run too warm. The oven should be about 140F and the oven door should remain open the entire time to allow moisture to escape. And since ovens frequently don’t hold the temperature accurately, the use of an oven thermometer (and frequent checking) is advised.
One last method of dehydrating food involves just leaving the food “on the vine.” Beans such as lentils, lima beans, kidney beans and more can be left in their pods on the plants until the plants and pods are dried and shriveled. At this point, the beans can be shelled and stored, but be sure that the beans are completely dry before storage, or they will mold. If you feel the beans are not dried enough, dehydrate them more using one of the above methods.
This might be one of the all-time favorite methods of preserving nature’s bounty! From beer to wine, fermentation can be our friend. But most people don’t realize that there is a huge array of food preservation via fermenting; even sourdough starter is considered a fermented, preserved food (it lasts for hundreds of years)!
Alcohol is just one form of fermentation, but fermentation by different types of bacteria include lactic acid, alkaline, and acetic fermentation. Lactic acid fermentation produces foods like yogurt, sauerkraut, and kimchi. Vinegars are the most common form of acetic acid fermentation, and include apple cider vinegar, kombucha, and wine vinegar. In alkaline fermentation, protein in foods is broken down into amino acids and peptides, and during the process ammonia is released giving the foods a distinct smell. Alkali fermentation is popular in countries in Southeast Asia and Africa, such as a soybean dish called natto in Japan, or dawadawa from African locust beans.
Jellying does not refer to the making of sweet fruit jelly (that’s a form of canning). Instead, jellying is a form of food preservation where the food to be preserved is cooked in a substance that forms a natural gel, thereby inhibiting bacterial growth by decreasing oxygen levels. The gelatinous substance is typically something like gelatin, arrowroot, or agar. Aspic is probably the best known form of jellying, where meat is potted (see below) in a combination of gelatin and meat broth.
Pickling is the use of an anti-microbial brew to preserve produce and meats. Typical pickling liquids include vinegar, brines, alcohol, and oils, and additional ingredients to flavor the food include salts, herbs, and spices. (Note: pickling in oil is not recommended for canning.) Pickling can be a form of fermentation for foods such as kimchi and sauerkraut, but in these cases the food itself is the preservative.
Popular forms of pickles include just straight-up cucumber pickles, but also delectable dishes from all over the world, such as the Italian giardiniera, pickled onions and eggs in British fish and chips shops, pickled herring in Scandinavia, and Achar in India, a pickle made from mangos, lime, vegetables, and an assortment of other ingredients.
Cooked meats were sometimes placed in hot earthenware crocks and pressed to eliminate as much oxygen as possible to preserve them. Then the meat was covered with a hot fat that hardened at room temperature, such as lard. The fat prevented oxygen from reaching the meats. Duck confit, potted shrimp, and Pâté are forms of potting, though potted meats traditionally were eaten by the British. It is crucial that as much oxygen as possible is eliminated from the meat, or bacteria will grow.
No discussion on food preservation would be complete without smoking, where meats and fish are cure-smoked with smoldering wood, which also serves to add a layer of desiccation to the preserving qualities of the smoke itself. Smoking is one of the oldest food preservation methods along with drying and burial, when food was cooked over open fires. Smoked meats traditionally were sliced thin and placed over a fire where three modes of preservation took place: The heat of the fire killed harmful microorganisms, some of the chemical compounds in the wood being used for smoking had an anti-microbial actions, and dehydration prevented degradation.
If you have any tips on any of these food preservation methods, please share them in the comments!