With these food preservation techniques, you can rely less on electricity and more on tried-and-true ways to preserve food: evaporation, fermentation, culturing, curing, and pickling.
A zeer keeps contents cool as water evaporates from damp sand or cloth between two clay pots.
Photo by London Permaculture
Before widespread refrigeration and electricity, people developed other food-preservation methods to slow down spoilage. Adopting some of these long-established ways to preserve food and relying less on modern ones will reduce your carbon footprint; increase your self-reliance; and cost less than canning, freezing, and other grid-dependent ways to preserve food. (Note: Home-preserved food may carry a slight risk of botulism or food poisoning. Find recipes tested for safety by the U.S. Department of Agriculture)
As you become familiar with these off-grid food preservation methods, you’ll be ready to try some recipes. Here are a couple of simple, delicious preparations that allow you to store food with traditional low-energy techniques:
Cool temperatures, such as those inside a refrigerator, don’t permanently preserve food, but they do significantly delay decay. The following practices helped people keep food cool long before the invention of refrigerators. You can use them — or your own solution for cooling and storing — when you try the recipes listed above.
Wet cloth wrap. Evaporation creates cooler-than-ambient temperatures, so simply wrapping a container of food in a wet cloth will help the food last longer than it would otherwise. The drier the surrounding air, the quicker the evaporation, and the more effective this method will be. Unfortunately, in a humid climate, the cooling effect will be negligible.
Zeer Pot. A zeer pot, or pot in pot refrigerator, is a small clay pot nestled within a larger, unglazed clay pot with damp sand or cloth stuffed between the two vessels. Like the wet cloth wrap, a zeer also works through evaporation. The food is placed in the central pot, which is then covered with a lid. Water evaporates from the sand or cloth through the porous outer pot — which is why using an unglazed pot is important — to cool the food within the smaller pot. If you choose this technique, you’ll need to add water to the sand occasionally, or stick one end of the cloth into a reservoir of water that it can wick up. Clay pot refrigeration also works best in arid climates where swift evaporation creates a significant cooling effect.
Cellaring. In climates too humid for evaporation to be an effective method of refrigeration, a cellar can keep food cool. Cellars maintain colder temperatures than aboveground locations in summer but stay above freezing during winter. They work well for most root crops, cabbage, cauliflower, and other sturdy vegetables, and they provide a place to store lacto-fermented foods after their initial room-temperature fermentation. Don’t own a cellar? You can also keep many vegetables in an unheated garage or basement (learn more about food storage).
If you leave pasteurized milk out at room temperature for two to three days, you’ll end up with spoiled milk. Try the same thing with raw milk, though, and you’ll have delicious clabbered cottage cheese. Many people don’t have access to raw milk, but even if you’re working with store-bought stuff, you can extend milk’s shelf life with the following processes.
Yogurt. Most yogurt cultures need temperatures between 100 and 110 degrees Fahrenheit to transform milk into yogurt. A yogurt machine, an oven with the pilot light on, and stove-heated milk in a thermos all work great but often require grid-generated energy.
If you use a woodstove to cook and heat, why not take advantage of the energy generated by the stove? Whisk a little yogurt into a jar of milk (1 tablespoon of yogurt per quart of milk), and put the jar near a warm woodstove for eight to 24 hours until the milk thickens into yogurt.
Kefir. As with yogurt, some instructions for making kefir start with heating the milk, but producing kefir at room temperature is possible. Stir kefir grains into milk and leave the mixture out for a few days. Strain out the kefir grains, and set them aside to start your next batch.
Maintaining live kefir grains is a bit like keeping a sourdough starter alive. You need to “feed” the kefir regularly — by covering the grains with milk after you strain them from a completed batch — and you’ll probably end up with more than you need. It’s easy to get a kefir starter from other enthusiasts, even through social media or Craigslist.
Scandinavian dairy cultures. Unlike standard yogurt strains, several Scandinavian fermented milk products culture at about average room temperature. Viili is a type of yogurt with a ropy consistency. Filmjölk has a custard-like texture and a lightly sour taste. Piimä is thin when made from milk, but when made from cream, it yields a sour-cream-like topping. You can find starter cultures for these Scandinavian dairy products online, such as at Cultures for Health, or you could post a query on social media or Craigslist to find people selling heirloom cultures in your area.
These products come with instructions if you purchase them, but generally you’ll just need to stir your activated starter or a tablespoon of yogurt from a previous batch thoroughly into cold milk, and then cover it lightly, and let it sit in a warm spot (70 to 77 degrees) for 12 to 18 hours until it thickens and sets. Then, cool it (in a refrigerator or with your method of choice) for six hours before eating. Save a tablespoon of yogurt to start your next batch. As with kefir, feeding your yogurt cultures at least every week (by making a new batch) will keep them thriving.
When finished, keep all of these cultured dairy products cool in a refrigerator or using another method.
The lacto-fermentation process produces traditional dill pickles, kimchi, and sauerkraut and requires nothing more than salt, vegetables, and water.
The simple process works because lactobacilli bacteria, present on nearly all raw vegetables and fruits, convert lactose to lactic acid, which makes an environment too acidic for other bacteria. The salty brine combined with the continued thriving of the lactobacilli bacteria preserves food and contributes to the tangy flavor of ferments.
You can lacto-ferment any vegetable. Fully submerge vegetables in a light salt brine, cover them loosely, and leave them at room temperature until fermentation begins. When the liquid becomes slightly bubbly on the surface and smells lightly sour, transfer your brew to a cooler location, which will slow fermentation and thus keep the texture and quality of the food at its best. The longer you let the fermentation process happen, the bolder the taste will be, so sample your ferments as they age to determine how long you prefer to ferment various vegetables. To experiment with different flavors, try adding a smashed clove of garlic, some diced hot chili peppers, or sprigs of dill or other herbs.
Although pickles made with diluted vinegar require canning or refrigeration for long-term storage, those made with undiluted vinegar can be stored at room temperature without canning. Be sure to use vinegar with 5 percent acetic acid or higher. Check the labels of any commercial vinegars to verify their acidity.
To preserve using vinegar, fill a clean glass jar with vegetables which you have either pierced with the tip of a paring knife or sliced. Cover the food completely with 5-percent-acidity vinegar and screw on the lid. Don’t dilute the vinegar with water.
This method will result in a sour pickle, and not all foods are tasty when preserved this way. But some full-strength vinegar pickles are delicious, including cornichons (small cucumber pickles) and hot chili peppers. You can also make aromatic vinegars by steeping herbs in undiluted vinegar.
Pickled hot chili peppers. For small peppers: Leave the peppers whole, but prick each pepper with the tip of a paring knife so that the vinegar can penetrate. For jalapeños and other larger chiles: Remove the stems and cut crosswise into circles between 1/8- and 1/4-inch thick.
Place peppers in a clean glass jar (unsterilized is fine), cover them with full-strength vinegar, and screw on the lid. Don’t use a metal lid, as vinegar will cause it to corrode. Keep your jar of peppers in a cool place.
Covering food in oil to seal out air and prevent mold is an ancient technique. However, oil will seal in bacteria that’s present on food. Because some bacteria, such as Clostridium botulinum, are anaerobic (meaning they don’t need oxygen to live), they could become a hazard. First use another method to kill off harmful bacteria (see below), and then use oil or rendered fat to seal out air and store the food.
For animal products, such as duck confit, first salt-cure the meat, slow-cook it, and then cover it in fat.
For vegetables, boil them in full-strength vinegar for 10 minutes. Then, drain off the vinegar and cover the food with a high-quality oil, such as extra-virgin olive oil. Try this with zucchini, eggplant, and mushrooms, which will make something like an Italian antipasto.
Store your oil- and fat-preserved foods in a cool environment, such as a cellar or a zeer.
Dried fruits, vegetables, and meats have a long shelf life. You can store them at room temperature, they’re lightweight, and they take up less space than fresh ingredients. Solar dehydrators capture the sun’s heat and provide enough air circulation to whisk away moisture from the sun-warmed food. Dehydrators also protect drying food from dust, insects, and overnight dew. To learn how to make your own dehydrator from super simple components, read A Solar Food Drying from Cardboard Boxes.
Leda Meredith is the author of five books, including Preserving Everything: Can, Culture, Pickle, Freeze, Ferment, Dehydrate, Salt, Smoke, and More. An instructor at the New York Botanical Garden and the Brooklyn Botanic Garden, she specializes in edible and medicinal plants.
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