Food preservation was once integral to humanity’s survival-strategies toolbox. We had to have something to eat when nothing fresh could be picked. As such, our ancestors invented numerous simple ways to keep foods fresh well into winter. Today, in the age of electric refrigerators and freezers, food preservation is more often aligned with the renaissance of conscientious eating—making use of locally grown or homegrown ingredients.
Ever since people began to look for ways to make food edible over a longer period of time, we’ve turned to the handy techniques and ingredients that follow to make it possible. Often two or three of these techniques are combined into one preservation recipe. (For example, pickles may be preserved by combining salt, sugar, vinegar and heat. Smoked and oil-preserved foods also rely on cold storage to extend shelf life.)
Summer’s end, ripe with abundance, is the perfect time to try your hand at these old-fashioned skills. Eugenia Bone, author of Well-Preserved, says food preservation is “an act of optimism” that actually slows down her relationship with food. If you care to join Bone and thousands of others who are having fun making food last longer and taste better, take our tour of the ingredients we’ll call upon to do the good work for us.
Salt, Sugar and Oil
Salt, sugar and oil work by depriving oxygen from the microbes that spoil food. These methods have the added benefit of contributing loads of flavor and allowing microbes that preserve food to take hold.
Cover food in salt or a salty brine and the right microbes will thrive while spoilage-inducing bugs are suppressed. Almost any fruit or vegetable can be preserved this way. A byproduct of this fermentation process is that the helpful bacteria produce B vitamins and numerous, complex new flavors. In addition, these probiotic critters are well-documented to improve digestive and immune function. Examples include sauerkraut, brined cucumber pickles and preserved lemons.
Common sugar-preserved foods include jams, syrups and fruits packed in syrups. These are usually canned, stored in the refrigerator or frozen. Healthier sweeteners such as honey and maple syrup can often replace white sugar in a recipe, but they add their own flavor profile.
Oil-preserved foods, such as roasted peppers and tomatoes covered in olive oil, will last much longer than their fresh counterparts, but still need to be refrigerated.
Vinegar and Smoke
Vinegar and smoke preserve food through acidification. Smoking acidifies the surface of ingredients and is usually accompanied by salt-curing and cold storage. Probably more important than its preservative qualities, smoke adds a depth of flavor to meats, vegetables, nuts, salt and even sweet fruits.
Acidification through vinegar is better known as pickling. Pickle recipes are often combined with another preservative ingredient—usually sugar, salt or heat (via canning). Vinegar pickles can be sweet or sour. Traditional examples include bread and butter pickles, sour gherkins, dilly beans and pickled beets. Most relishes also fall into this category.
Alcohol is both an ingredient that can be called upon to preserve food (because it kills bacteria) and a product of food preservation in which the preserving ingredient is yeast (as in beer, cider, mead and wine).
Air is the simplest form of food preservation. Dehydrating food in open air is likely the oldest method of food preservation. Set food in a warm place, ideally with circulating air, and eventually it loses enough of its moisture (75 to 90 percent) to deprive any food-spoiling microbes from the conditions they need to survive. Herbs are the easiest foods to dry because they contain little water. For tips on preserving herbs see How to Preserve Fresh Herbs. Fruits, vegetables and meats can also be dried into leathers and jerkies—via warm air from either the outdoors, the oven or a dedicated food dehydrator. See how to make your own in How to Build a Solar Food Dehydrator. To bone up on dehydrating skills, check out Food Drying with an Attitude by Mary T. Bell.
Cold storage works wonders on the shelf life of almost all foods. If you have a cool spot in your house (check the corner of a closet, basement or unheated garage), you can store a number of summer harvest items, including onions, garlic and most root vegetables, through all or part of winter.
The refrigerator and freezer are obvious choices for cold storage, but you may be surprised how little tips and tweaks can improve the quality of refrigerated and frozen food. For more ideas on making food last longer in the fridge, check out How to Keep Food Fresh Longer.
• Some foods—whole berries and strips of sweet pepper, for example—freeze perfectly well as is.
• If freezing foods in canning jars, always leave headspace: 1/2 inch for wide-mouth pints and 1 inch for wide-mouth quarts.
• If using baggies, always use freezer bags, which are thicker and less prone to freezer burn, to ensure the longest possible storage.
• For most foods, blanch by steaming or boiling to maximize color, flavor and nutrition. For a list of blanching times for various foods, visit the National Center for Food Preservation. Immediately after blanching, chill food in ice water, then pat dry and store in airtight freezer containers.
• Freeze individual items on cookie sheets until solid, then combine items in containers. You can later pull out only the amount you need.
Heat works by killing spoilage-inducing microbes. Water-bath canning, the simplest method, works well with foods that are somewhat acidic, such as fruit and pickles, because acid is also a preservative. If you find the idea of canning daunting, try Ball’s automatic canner, which makes the process even simpler.
For foods that don’t contain much acid, use the pressure canner. Canning recipes must be followed carefully to ensure safety. To learn more about canning, visit Easy Home Canning Recipes.
For more recipes and information about the food preservation methods discussed here, you can’t go wrong with these books, many of which are available on our shopping page.
The Art of Fermentation by Sandor Ellix Katz
The Big Book of Preserving the Harvest by Carol W. Costenbader
The Busy Person’s Guide to Preserving Food by Janet Chadwick
Food in Jars by Marisa McClellan
Food Drying With An Attitude by Mary T. Bell
The Joy of Pickling by Linda Ziedrich
When it comes to food preservation, Tabitha Alterman is currently enamored of all things fermented, particularly whole grains. Her whole-grain baking cookbook will be out this winter.