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- What Is Food Preservation?
- Why Preserve Food at Home?
- 11 Types of Food Preservation Techniques
- Preserving By Dehydration: How to Make Dehydrated Fruit:
- Preserving With Yeast: How to Ferment Vegetables:
- Preserving in Alcohol: How to Make Homemade Vanilla Extract
- Preserving in Salt: How to Cure Fish With Salt and Sugar
- Preserving in Vinegar: How to Quick Pickle Vegetables
- Preserving in Oil: How to Preserve Sun-Dried Tomatoes in Olive Oil
What Is Food Preservation?
Food preservation refers to a variety of techniques used to prevent food from spoiling. Methods of food preservation include:
- Freeze drying
Maintaining nutritional value, texture, and flavor are key aspects in food preservation.
Why Preserve Food at Home?
If you want to enjoy market produce all year round, preserving food at home can be a healthy and cost efficient option. Enjoy the bounty of summer deep into the winter season with berry jam, pickled peppers, and brandied cherries using our preservation methods below.
11 Types of Food Preservation Techniques
- Cool Temperature Storage. Cold food storage is the simplest food preservation method. It occurs in refrigerators and cool, dark places such as: root cellars, unheated basements, and pantries. Cooling preserves food by slowing down the growth of microorganisms that cause the food to spoil. Before the refrigerator was invented, cooling for food storage was common in root cellars and iceboxes. Ideal foods for root cellar storage are: potatoes, yams, onions, garlic, apples, cabbage, turnips, beets, carrots.
- Food Drying. Drying foods inhibits the growth of bacteria, yeasts, and mold through the removal of moisture content. Dehydration has been practiced since ancient times with prehistoric peoples sun-drying seeds. Electric food dehydrators, ovens, and freeze-drying are now speeding up the process that was traditionally done by sun and air. Foods that dehydrate well are fruits, vegetables, legumes, spices, meat, and fish.
- Canning: Water Bath. In the 1800s, a French cook named Nicolas Appert, known as the “father of canning” invented the packing, heating, and sealing technique that we still use today for food products. The process involves placing foods in canning jars and heating them to a high temperature to destroy the microorganisms that cause food to spoil. During the heating process, air is pushed out of the jar, and as the cans cool, a vacuum seal forms. Canning in a bath of boiling water is ideal for high-acid foods, like fruits and fruit juice, pickled vegetables, salsa, chutneys, vinegars, and condiments. Water bath canning requires extended cooking time at a low temperature temperature to destroys the mold, yeast, and enzymes that cause spoilage while making a vacuum seal for long-term storage.
- Canning: Pressure Canning. The second primary type of home canning, pressure canning uses high temperatures (240°F) and special equipment to preserve low-acid foods, like vegetables, dairy, meat and seafood, legumes, and soups.
- Freezing. Freezing foods uses little specialized equipment, while preserving fresh flavors and textures. Freezing slows the growth of microorganisms and enzymes that can cause food spoilage. For the best results, freeze room-temperature foods, remove all the air from the freezer bag, and consume within 6 months of freezing. Sealing frozen produce in vacuum-sealed bags prevents ice crystals from forming and can extend the shelf life of food.
- Freeze-drying. Freeze-drying is a low-temperature dehydration process that involves freezing food and removing the ice by sublimation—turning ice into vapor. This method can be done in a freezer (takes several weeks), on dry ice, or using a modern freeze-dryer unit, which can take less than 24 hours.
- Fermentation. Fermentation is a chemical reaction in which microorganisms, such as bacteria or yeast, convert carbohydrates to alcohol or organic acids under anaerobic conditions. This process creates some of our favorite funky foods like cheese, yogurt, kombucha, sauerkraut, kimchi, and sourdough bread.
- Preserving in Salt and Sugar. Before industrial refrigeration, most foods were cured using sugar, salt, or a mixture of both. Salt and sugar reduce the water content and inhibits microbial growth in meats, fruits, and vegetables aiding in preservation. Common sugar-preserved foods are jams and jellies, while salt cod, salt pork, corned beef, and bacon are common foods preserved with salt.
- Alcohol. Fruit has a long history of getting preserved in alcohol. During the eighteenth century in Europe, fruits like peaches, cherries, and apricots were submerged in brandy and served as dessert after a meal. Alcohol draws water out of food, similar to salt and sugar, inhibiting microbial growth. This method is great for making extracts and infused alcohols, like cordials and rumptopf, a German method of preserving summer fruit in alcohol.
- Vinegar Pickling. Vinegar pickling creates a high acid environment that kills off microbes and causes food to change in flavor and texture. Vinegar, salt, and sugar are heated and added to fruit or vegetables to make pickles of cucumber, okra, apples, beets, peppers, carrots, onions, cauliflower, green beans, and plums.
- Olive Oil Preserving. Extra-virgin olive oil is a natural preservative that prevents spoilage by isolating food from air, providing a seal that can slow down oxidation and molding. It is used for preserving fresh herbs, vegetables, and fish. It’s important to keep food safety in mind when storing vegetables such as garlic, mushrooms, chili peppers, or herbs in oil—these low-acid foods can be a source of bacteria and should be stored in the refrigerator as a precaution.
Preserving By Dehydration: How to Make Dehydrated Fruit:
Wash and dry fruit. Peel the fruit if the peel isn’t edible. Slice the fruit into ½-inch cubes, removing any seeds, and coat with fresh lemon juice. Spread fruit slices in one layer onto dehydrator racks or parchment paper-lined baking sheets. Set a dehydrator to 135ºF and dehydrate for 6 to 8 hours until dried and crisp. Alternatively, in a 200ºF oven: bake fruit slices for 2 to 3 hours, flipping halfway through, until the chips are crisp. Store all dried fruit in an airtight container in a cool and dark place.
Preserving With Yeast: How to Ferment Vegetables:
Place 2 cloves of garlic in the bottom of a clean glass quart-sized jar. Layer 3 cups of cut vegetables (such as cauliflower, carrots, cabbage, or green beans) into the jar, leaving 1 to 2 inches of headspace. Add any seasonings into the jar, such as caraway seeds or peppercorns. Dissolve 2 tablespoons of salt in 1 quart filtered water and pour over the vegetables until the tops are covered. Tightly seal the container and ferment at room temperature (60 to 70 degrees is ideal) for about 5 days, tasting to desired flavor. Burp the jar daily to release excess pressure. Once they are finished, move to the refrigerator for storage.
Preserving in Alcohol: How to Make Homemade Vanilla Extract
Cut 5 whole vanilla beans in half lengthwise. Place the beans in an 8-ounce jar and cover with 1 cup of vodka. Screw on the lid and shake to combine. Place in a cool, dark place for at least 2 months. The longer the vanilla sits, the stronger the flavor will be.
Preserving in Salt: How to Cure Fish With Salt and Sugar
Rinse and dry one 2-pound piece of salmon (or other fatty fish like tuna, mackerel, trout, or cod). In a medium bowl, combine ½ cup of sugar with ½ cup kosher salt, and rub over the entire fish; sprinkle with ½ cup fresh dill leaves. Wrap tightly with several layers of plastic wrap, place in a shallow glass dish, and weigh down with a heavy pan. Place in the refrigerator and cure for 2 to 3 days, turning over after 24 hours. Cured fish can be stored in the refrigerator for up to 3 days.
Preserving in Oil: How to Preserve Sun-Dried Tomatoes in Olive Oil
Rehydrate ½ cup sun-dried tomatoes by simmering them in a large pot with 2 cups of hot water and 2 cups of red wine vinegar until they are plump, about 5 to 10 minutes. Remove from heat and let sit another 5 minutes, then drain and dry with paper towels. Transfer the tomatoes to a glass jar, add 1 teaspoon dried oregano and a pinch of chili flake, then fill the jar with olive oil, making sure the tomatoes are completely covered in oil. Store in the refrigerator for up to 3 months.