13 Food Preservation Techniques

When it comes to long-term food storage, there are thirteen options for preserving food. Use these methods to preserve garden produce, dried foods, and even things like meat. Each food type and preservation technique has more or less shelf-life. Some foods need to be rotated due to their shorter shelf life. Used together, the techniques cover all the bases.

Following is what I learned about food preservation research for my emergency pantry. I hope the information helps you as you plan yours. Here are the 12 most common types of food preservation.

13 Long-Term Food Storage Methods

1. Canning
2. Pickling
3. Freezing
4. Smoking
5. Dehydration
6. Freeze-Drying
7. Oxygen-Free Storage
8. Sugar Curing
9. Salt Curing
10. Alcohol Preservation of Fruit
11. Vacuum Packing
12. Fermentation
13. Potted Meat

#1 Canning

Canning can be used to preserve most food types as long as it is done correctly. Vegetables, soups, stews, and even meat can be preserved this way. Most preppers start canning excess garden produce for the winter months. This is a good way to get started.

Canning food for preservation places food-filled jars in boiling water to kill bacteria and create a vacuum seal. Low acid foods with Ph values higher than 4.6 are pressure canned at temperatures of 240°F to 250°F. High-acid foods are water bath canned at lower temperatures.  

Why Can Food For Preservation?

Canning foods is an excellent way to preserve fruits, vegetables, and meat. It complements growing your own garden vegetables because you can preserve large bounties of fresh food too large to store fresh. Plan ahead to make sure you have enough vegetables to get you through the off-season.

How long will it last?

The United States Food and Drug Department suggests consuming home-canned food within 1 year, so it’s fresh and nutritious. Home-canned foods will last for years, but the quality and nutritional value of food declines the longer it’s stored.

Two Methods of Canning: High and Low Acid Food(s)

There are two canning methods used to control botulinum bacteria. Which method you choose depends on the acidity level of the food being canned.

1. Water Bath Canning: Used for high acid foods. Jars of food are immersed in a pot of water with the lids loosely sealed and boiled for x amount of time depending on the food type and a tested recipe. Don’t guess use a recipe.
2. Pressure Canning Method: For low acid foods with pH values higher than 4.6 including red meats, seafood, poultry, milk, and all fresh vegetables. Jars of food are placed in 2″ to 3″ of water inside a canning pressure cooker which is heated to temperatures of 240°F to 250°F. These temperatures are only reached by pressure canning. Don’t guess, use a tested recipe.

Acidity may be natural, as in most fruits, or added, as in pickled food….low acid canned foods are not acidic enough to prevent the growth of [Botulinum] bacteria. Acid foods contain enough acid to block their growth. Increase acidity levels of food by adding lemon juice, citric acid, or vinegar. All low acid foods should be sterilized at 240° to 250°F attainable [only] with a pressure canner.

United States Department of Agriculture

Table 1. Examples of low and high acid foods and the required canning method

Low-Acid Foods Pressure Canning	High Acid Foods Boiling Water Bath Canning
Most Vegetables	Most Fruits
Asparagus	Apples and Apple Sauce
Beets	Apricots
Carrots	Berries
Green and Dried Beans	Cherries
Okra	Grapes
Peas	Jams and Jellies
Peppers	Peached and Nectarines
Potatoes	Pears
Pumpkin	Pie Filling (fruit only)
Sweet Corn	Plums
Meats	Acidified and fermented foods
Beef and Poultry	Chutneys
Seafood	Pickled Vegetables
Wild Game	Pickles
Combination Foods	Salsa
Meat Sauces	Sauerkraut
Soups and Stews	Tomatoes (acidified)

If you are interested in canning, check out The Complete Guide to Home Canning: Guide 1, Principles of Home Canning, United States Department of Agriculture under the sources down below.

#2 Pickling

Pickling for preservation is basically just adding acid before food storage to prolong shelf-life. We’re all familiar with “pickles,” a cucumber emersed in a bath of brine or vinegar. The cucumber is a low-acid food prone to food poisoning like botulism, so acid needs to be added before pressure canning.

What is pickling?

Pickling is a food preservation technique that increases the acid level of low-acid foods by fermenting vegetables, fruit, meat, fish, dairy, and eggs in an immersion of salt brine or vinegar. After pickling, food items are pressure canned to seal the container, kill bacteria and create a vacuum seal.

Two Types of Pickling

1. Brined Fermented Pickling

Pickles are brined in saltwater for several weeks at room temperature. This process is called curing and actually ferments the pickle by growing good bacteria that produce acid. The acid produced kills bacteria that would otherwise spoil the vegetables being cured.

Once fermented, Brined Pickles are pressure canned for long-term storage. Methods and ingredients vary depending on a proven recipe.

2. Unfermented

Unfermented Pickles are made with vinegar to increase acidity and kill bacteria.

Warning: Pickle recipes need to be tried and tested to ensure food is safe for consumption. Only use tested recipes. To learn more about how to pickle, check out the article from Oregon State University, “Pickling Vegetables,” under the sources down below.

#3 Freezing

Freezing is an excellent method of preserving food because it maintains nutrients, texture, color, and flavor.

Foods are preserved by freezing when the moisture present in food is frozen, stopping bacterial growth and slowing enzyme function to keep food from spoiling.

6 Advantages of Freezing Food

1. It saves time and money
2. Easy Method of food preservation
3. Simple meal prep
4. Provides foods quickly for heating up and eating
5. Supplies seasonal or favorite food(s) all year round
6. Allows you to stock up on foods when on-sale

Freezing Foods, University of Tennessee, Institute of Agriculture

2 Reasons Not To Freeze Food For Preservation

1. Freezer Space Is Limited. More than likely, your freezer is already packed with frozen foods and leftovers.
2. Freezers Don’t Work When The Power Is Out. Not ideal for emergency preparedness.

Storage Tip: Freezing won’t improve the quality of food and it won’t kill bacteria. If the food is bad going into the freezer it will be bad coming out.

How Long Does Frozen Food Last

Expect frozen foods to keep from 1 month to 1 year to maintain quality. Foods are safe to eat if left in the freezer longer, but they may be freezer-burned and of poor quality.

Table 2 Avoid Freezing These Foods For Preservation

Don’t Freeze These Foods	Why You Don’t Freeze These Foods
Hard-Cooked Eggs	Egg Whites Get Tough and Rubbery
Mayonnaise and other salad dressings	They separate when frozen
Salad Greens and Other Raw Salad Ingredients: egg, chicken, ham, tuna, and macaroni	Lose Crispness and take on off-flavors
Sandwiches Containing Ingredients listed Above	–
Cream Pie Fillings & Custards	Separate and Become Watery
Raw Potatoes	Darken, undergo texture changes like mealiness
Gelatin Salads or Deserts	Weep
Unbaked Cake Batter	Fails to rise
Sour Cream	Separates when frozen alone: combine with other ingredients like sugar or cream cheese
Meringue	Shrinks become tough and gummy
Sage, black pepper, cloves, artificial vanilla,	Develop Bitter Flavors
Uncooked garlic and onions	Flavor Strengthens
Cake icings made with egg whites	Become Frothy and Weep
Fried Foods	Lose Crispness
Sauces, gravies, pie fillings, and puddings	separate or curdle
Eggs In Shell	Yolk becomes thick and will not blend with whites
Canned Foods Labeled Keep Refrigerated Unopened	The liquid inside expands and may cause the can to explode

Wash Fruits and Vegetables Before Freezing

Wash vegetables before freezing and cut out any bad spots like bruises. This will give you a better product out of the freezer. Wash in clean water but don’t soak or you’ll remove vitamins and minerals. Washing will:

• Decrease microorganisms
• Remove dirt
• Remove some pesticides
• Remove insect eggs
• Increase the visibility of damage that can be cut out

How To Thaw Frozen Food

When thawing frozen food the main thing you want to avoid is the outside thawing while the inside is still frozen. Bacteria will start to multiply on the outside before the center is thawed. Here are three tips to thaw food.

1. Place your food package in the refrigerator in another container or on a towel to keep food from dripping on other items. Don’t thaw food at room temperature. Bacteria will blossom on the exterior while the interior is still thawing.
2. Place package in cold water in a Ziploc freezer bag
3. Use a Microwave and defrost

Storage Tip: You don’t have to thaw fruits and vegetables before cooking.

#4 Smoking Meat

Smoking meat is done for preservation, tenderness, and flavor. If you are interested in longer shelf life, you will want to know about cold smoking. So what is smoking?

There are two methods of smoking meat. The first is hot smoking, a BBQ type using offset heat, light brine, and smoke to improve flavor and texture. The second is cold smoking, which includes heavily curing meat with salt and extended treatment with cold smoke. Cold smoking is for meat preservation. 

4 Ways Smoking Meat Stops Bacterial Growth

1. Meat is cured with salt, which dries meat and inhibits bacterial growth
2. The smoke itself is antimicrobial.
3. Heat kills bacteria.
4. As the meat smokes, it dehydrates, inhibiting bacterial growth. 

Warning: Only completely thawed meat, poultry, and fish should be smoked

Does Smoking Preserve Vegetables?

Vegetables and other non-meat foods are not preserved by smoking, but it does impart excellent flavor and texture. Vegetables are normally preserved long-term by pickling or pressure canning.

Two Types of Smoking:

1. Hot Smoking: uses indirect heat and smoke to cook meat for a short period of time. The meat is eaten immediately or refrigerated for 3 to 4 days. Hot smoking provides a tender end product imparting flavor and texture. This method is not used for long-term preservation.
2. Cold Smoking is an ancient method used to cook meat with smoke and little heat. It takes 12 to 24 hours over a smoldering fire below 85° F. Meat must be heavily fermented, salted, or cured before cold smoking. If properly smoked, the meat will l

Curing and Smoking Meats for Home Food Preservation, USDA

Table 3 Minimum Required Hot Smoking Temperatures

Meat Type	Internal meat temperature to kill Clostridium botulinum Type E
Beef and Pork	145° F
Poultry	165° F
Fish	150° to 160° (higher than the traditional cooking temperature of 145°) Fish Must be Salt Brined to kill bacteria before smoking

Fish 150° to 160° (higher than the traditional cooking temperature of 145°

#5 Dehydration

Dehydrating food reduces the weight of food making it ideal for a bug-out bag, hiking or backpacking.

What is food dehydration?

Food Dehydration is a food preservation technique that removes water or moisture from food.

How Does Dehydration Preserve Food?

Dehydrating food creates an environment less hospitable to the things that spoil food by removing moisture. The Enzymes and micro-organisms that spoil food need moisture to thrive. In a low moisture environment, enzyme reactions slow, and it is harder for bacteria, mold, and yeast to get a foot-hold.

6 Methods Used To Dehydrate Food

1. Sun Drying: Use to dehydrate fruit, not recommended for vegetables or meat. Pick a day when the sun is shining, humidity is low, and temperatures are 85°F or above. The biggest challenge will be keeping the bugs at bay.

2. Air Drying: Place spices and herbs in the shade and let nature do its thing. Used for delicate herbs and spices that will get scorched by the sun

3. Conventional Oven: Dry foods at 140° F or less. Higher temperature will cook food instead of drying it.

4. Solar Drying: foods are dried using a concentration of the suns power with the greenhouse effect

5. Food Dehydrator: An electric dehydrator is the fastest most efficient method of dehydrating food.

6. Microwaving: Use the defrost cycle on your microwave to dehydrate fruits and herbs

Three Elements of Food Dehydration

1. Heat: 140° F or less, any higher and you cook the food.
2. Dry Air or Low Humidity: Dry air will absorb moisture. Humid air will not.
3. Air Movement: Carries moisture away from the food.

Table 4. Fruits and Vegetables You Can Dehydrate

Fruits	Vegetables
Apples	Beets
Apricots	Carrots
Bananas	Sweet Corn
Cherries	Garlic
Coconuts	Horseradish
Dates	Okra
Figs	Onions
Grapes	Parsnips
Nectarines	Parsley
Peaches	Peas
Pears	Peppers
Pineapples	Potatoes
Plums	Pumpkin
–	Mushrooms

#6 Freeze-Drying

Home freeze drying units like Harvest Rights are expensive but if you actually use them to store bulk food you will save money. Imagine purchasing expensive meats when they are on sale at ridiculously low prices and freeze-drying them. If freeze-drying food becomes a way of life it’s worth looking into.

What Is Freeze Drying?

Freeze-drying or lyophilization is a method of preserving food where water is turned to ice under a low-pressure vacuum and removed by sublimation. Sublimation means that moisture leaves food as a gas, skipping the liquid state.

8 Reasons Freeze-drying Is Better Than Dehydrating Food

Freeze-dried foods have superior color, texture, nutrition, and shelf-life when compared to heat-dehydrated foods. The basic difference between the two types of preservation; freeze-drying uses freezing temperatures, and heat dehydration uses heat.

Heat is much tougher on food, and it doesn’t do as good a job at removing moisture, the #1 cause of food spoilage.

Table 4. Eight Reasons Freeze-dried Food Preservation Is Better Than Dehydration

Characteristics	Freeze-dried Food	Dehydrated Food
1. Method of Dehydration	Deep-freezing in a vacuum	Heat*
2. Shelf-Life**	25 to 30 Years	Self-processed: 1 to 10 Years Commercially Processed:15 Years
3. Retained Nutritional Value	95% to 97%	40% to 60%
4. Taste	High Quality	Loss Of flavor
5. Moisture Removed	95%	60% to 80%
6. Prepping Time To Eat	12 Minutes	20 to 30 Minutes
7. Stock Rotation	Not-required	Required
8. Do It Yourself Method Of Producing	Home Freeze Dryer	Electric Dehydrator

#7 Oxygen-Free Storage

Oxygen reduces the quality of food over time by a process called oxidation. Eliminate oxidation by storing food with an Oxygen absorber(s) in a sealed container such as a Mylar bag. This is the best method for preserving dried foods like white rice, dried beans, and hard grains.

4 Benefits of Oxygen-free Storage

1. Shelf life Increased by decades (white rice, wheat, and dried beans will last 30 years if stored properly)
2. Prevents the growth of aerobic bacteria and micro-organisms
3. Kills bugs, pupae, and eggs within two weeks
4. Eliminates the need for food preservatives
5. Stops Vitamins From being oxidized
6. Preserves Flavor

Types Of Foods You Should Not Store Oxygen-free

Foods high in moisture, above 10%, and high in fat should not be stored in an oxygen-free container.

If you store high moisture foods in an oxygen-free container you risk anaerobic bacteria like botulism.

Foods with a high oil content will go rancid whether oxygen is present or not. This is why white rice with no oil stores for 30 years and brown rice with the husk and oils present has a shelf-life of less than a year.

Table 5. Foods Typically Stored in Oxygen-free Containers:

Foods Stored In Oxygen-free Containers	Shelf-life (Years)
White Rice	30
Dried Beans	30
Legumes, Lentils, and Dried Peas	30
Hard Grains	30
Soft Grains
Dried Pasta	30
Freeze-dried Food	30
Rolled Oats	30
Grain Corn/ Dent Corn	30
Heat -dehydrated vegetables with 10% moisture or less.	–
Heat-dehydrated fruit with 10% moisture or less	–
White Granulated Sugar (No O2 Absorber Required)	Indefinite
Salt (No O2 Absorber Required)	Indefinite
Baking Soda
Powdered Fat-free Milk	20

#8 Sugar Curing For Food Preservation

Sugar curing will preserve meats like pork, and fruits and canned fruit like jams and jellies. In modern times the most common use of sugar for curing is to make preserves. There are still people who cure Christmas hams and other cuts of meat but it’s not as popular today as it once was.

3 Methods of Preserving Food With Sugar

• Dehydrate fruit and meat by dry-packing in granular sugar
• Sugar Syrup is a combination of salt, sugar, molasses, and spices to cure a Ham or other meats like bacon
• Cooked in sugar until crystalized, often used for pastries and sweet treats

How Does Sugar Preserve Food?

Sugar preserves food by creating an environment inhospitable to the organisms that spoil it. Sugar does this by dehydrating food through osmosis, drawing water out of cells, and replacing it with sugar. This osmosis effect slows enzymes and kills the cells of mold, yeast, and bacteria that spoil food.

Preservation Note: Honey is loaded with sugar and can be used to preserve food. Both honey and sugar have an indefinite shelf-life.

Foods You Can Preserve With Sugar

• Beef
• Bacon
• Ham
• Fruit
• Jams
• Jellies
• Vegetables

#9 Preserving Meat With Salt

Salting is a preservation method that dehydrates or dries meat. Without moisture, it is harder for bacteria to get established so salting increases shelf-life.

2 Types of Salt Curing

Dry Curing: Pack meat in salt or salt with nitrates and nitrites to remove moisture and create meat with a beef-jerky-like texture.

Brining: a bath of salt and water. Also called wet curing or pickling.

Table Salt VS. Curing Salt

Curing salts are table salt with the addition of sodium nitrite or sodium nitrate. These salts are used to preserve meat like sausages long-term. Curing salts are toxic to humans and can be lethal in the wrong dose. They are tinted pink to distinguish them from regular table salt.

#10 Alcohol Preservation Of Fruit

Here we’re talking about adding alcohol to preserve fruit, not fermentation. It is ideal for preserving fruit for special occasions like Christmas celebrations and cold winter months when the fruit is unavailable. Such a preserve also reduces pallet fatigue from an otherwise dull survival menu.

Can I Use Any Alcohol To Preserve Fruit?

Use any alcohol to preserve fruit as long at it is at least 80 proof or 40% alcohol by volume.

Rumtopf or German Rum Pot was traditionally made by adding fresh fruit to a bath of brandy or rum for preservation during long ocean voyages. You can make this dish with just about any fruit minus bananas and just about any alcohol as long as it’s 80 proof or higher.

Make sure the fruit is covered in rum and use sugar to taste. Adding sugar cuts down the rum flavor.

Peaches Preserved With Rum

Here are a couple of excellent recipes from St. Andrews Golf Club in Scotland. The Peaches in rum look especially tasty. PDF All of the ingredients, minus the fruit and cinnamon, have an indefinite shelf life, so you could use store them in long-term storage and use them until you run out.

Peaches In Rum:

• 1 3/4 cups Sugar
• 1 1/4 cups of Water
• 2 cinnamon sticks broken in half
• 6 large ripe but firm peaches
• 3/4 cup white or dark rum

Alcohol for tinctures

To make tinctures, dried or fresh herbs are soaked in alcohol to concentrate the active ingredients. They can also be made using vinegar. Some believe that tinctures have health benefits, but I’m not a doctor, so I can’t attest to this.

Different tinctures are made with herbs you can grow in your gardens such as chamomile, garlic, ginger, and many more.

#11 Vacuum Packing

Vacuum packing food extends shelf-life by removing oxygen. Expect foods to last three to five times longer than food stored in a Ziploc bag or Tupperware. Vacuum packing also reduces the package volume ideal for backpacking or bug-out bags.

Vacuum packing also protects food from dehydration and freezer burn but it is not as effective as using Oxygen absorbers at removing oxygen. For dried foods like white rice stick with oxygen absorbers for preservation.

How Long Will Vacuum Packaged Foods Last?

Table 6. How Long Will Vacuum Packed Food Last In the Freezer?

Food Type	Regular Storage	Vacuum Packed
Beef and Poultry	6 Months	2 to 3 years
Ground Meat	3 months	1 year
Fish	6 months	2 years
Soups and Stews	3 to 6 months	1 to 2 years
Coffee Beans	6 to 9 months	2 to 3 years
Vegetables	8 months	2 to 3 years
Bread	6 to 12 months	1 to 3 years

Table 7. How Long Will Vacuum Packed Food Last In The Refrigerator?

Food Type	Regular Storage	Vacuum Packed
Soft Cheese	1 to 2 weeks	4 to 8 months
Hard Cheese	15 to 20 days	40 to 60 days
Lettuce	3 to 6 days	2 years
Berries	1 to 6 days	1 to 2 weeks
Vegetables	2 to 7 days	7 to 14 days
Roasted Meat	2 to 3 days	8 t0 12 days
Whole Fish	1 to 3 days	4 to 5 days

Table 8. How Long Will Vacuum Packed Dried Goods Last At Room Temperature?

Food Type	Regular Storage	Vacuum Packed
Flour and Sugar	6 months	1 to 2 years
Dried White Rice & Pasta	6 months	1 to 2 years
Coffee	2 to 3 months	12 months
Cookies	1 to 2 weeks	3 to 6 weeks
Bread	2 to 3 days	7 to 8 days
Cereal	2 to 3 months	6 to 12 months
Nuts	6 to 8 months	2 years

Oxygen Absorbers VS. Vacuum Packing

Both Oxygen Absorbers and Vacuum packing have a place in your long-term food storage they just fulfill different needs. Following is a basic breakdown of both food storage methods.

Oxygen absorbers remove 99.9% of the oxygen from a food package, give a 30+ year shelf-life, and kill aerobic bacteria and bugs. O2 absorbers aren’t used to store foods higher than 10% in moisture content or foods high in fat due to anaerobic bacteria and the possibility of botulism forming. 

Vacuum packing is a good storage method for foods high in moisture or if you are looking to reduce the package volume for things like backpacker meals or a bug-out bag. Vacuum packing will increase food shelf-life up to 5x regular packaging, but you will not get decades of shelf-life.

#12 Fermentation

Fermentation is a method of preserving food where microorganisms turn starchy sugars into alcohol and increase nutritional value. Not to mention they are pretty tasty.

5 Reasons To Ferment Food For Preservation

• The natural method of preserving food without chemicals
• Improves the flavor and texture of food
• Increases nutritional value
• Inexpensive
• Preserves large quantities of fresh produce

18 Examples of Fermented Foods

Fermenting is primarily used to preserve bounties of fruit and vegetables when they are in season, and there is too much to consume fresh. Here are some examples of fermented foods, drinks, and condiments.

1. Beer
2. Wine
3. Cheese
4. Yogurt
5. Kefir
6. Sauerkraut
7. Natto
8. Kimchi
9. Pickles
10. Soy sauce
11. Miso
12. Tempe
13. Hamanatto
14. apple cider vinegar
15. kombucha
16. fermented meat
17. fish
18. vegetables.

#13 Potted Meat

This is an ancient method of preserving meat that doesn’t meet today’s requirements for preservation. This process is still used in parts of Canada and France to make Pate and Pork Rillettes.

Potting meat consists of first, cooking meat thoroughly, second, placing it in a sterilized earthen crock, and third pouring melted fat over the top. When the fat cools, it becomes a solid plug that seals the meat below once potted meat is stored in a cool, dry location.

Warning: This food preservation technique is susceptible to botulism, which is rare but deadly food poisoning caused, by anaerobic bacteria like Clostridium botulinum, Clostridium butyricum, and Clostridium baratti. Centers For Disease Control and Prevention

Modern Potted Meat

Modern potted meat is meat, meat by-products, water, salt, and other ingredients preserved with modern canning techniques that sterilize and seal the meat into a lined can. As long as the seal on the can is good, the meat will keep 5 years to indefinitely.

6 Examples of Modern Potted Meat

1. Spam
2. Vienna Sausages
3. Boiled Ham
4. Corned Beef
5. Armour Potted Meat
6. Pate

Sources:

Complete Guide to Home Canning: Guide 1, Principles of Home Canning, United States Department of Agriculture, National Institute of Food and Agriculture PDF

Purdue Extension, Health, and Human Sciences Let’s Preserve: Basics of Home Canning PDF

Pickling Vegetables, Pacific Northwest Extension Publication, Oregon State University, Washington State University, University of Idaho, PNW 355 PDF

Freezing Foods, The University of Tennessee Institute of Agriculture PDF

Using Dehydration to Preserve Fruits, Vegetables and Meats, Virginia Cooperative Extension, Virginia State University PDF

Fermentation as a sustainable method of food preservation, Sanjana Shrivastava, Lovely Professional University, Phagwara, Punjab PDF