Our grandparents used to spend their weekend’s canning veggies from their garden, smoking meat (often from game they caught themselves), and making real pickles.
Today, we have mostly lost this knowledge.
Even in the era of mega supermarkets, there are a lot of reasons to learn how to preserve food:
- You want to stockpile emergency food for disaster preparedness.
- You are homesteading and want to keep your surplus.
- You want food without additives and preservatives.
- You can buy food in bulk when it is cheap to save money.
- Or simply because of the tremendous personal satisfaction which comes with learning old skills and becoming more self-sufficient.
Food preservation can initially seem overwhelming with so many different methods and techniques.
This guide is meant to help you get started with DIY food preservation so you can choose the proper methods for your goals.
Table Of Contents
- What Causes Food to Spoil?
- Ways to Preserve Food
- Methods of At-Home Food Preservation
- Vacuum Sealing
- Oxygen Absorbers
- Freeze Drying
- Storing Dry Foods
- Storage Containers
- Long Term Food Preservation
- Foods Not Suitable for Long Term Storage
- Mylar Bags
- Oxygen Absorbers
- Long Term Shelf Lives of Food
What Causes Food to Spoil?
Before you can learn about food preservation methods, you have to understand why food spoils in the first place.
Five main factors will cause food spoilage:
Microorganisms refer to all bacteria, yeast, and molds that can grow in food.
As these feed off of the food, they produce waste products. These wastes are what give spoiled food a foul smell.
For most microorganisms to survive, they need oxygen and water.
Many food preservation methods work by limiting oxygen (such as vacuum packing) and water (such as dehydrating).
Note: Some bacteria do not require oxygen to grow (anaerobic bacteria). One of these is the infamous bacteria Clostridium botulinum, which is responsible for causing botulism.
Until canning techniques were improved, botulism poisoning was common.
Thus, foods must be heated adequately to kill botulism bacteria during the canning process. Most microorganisms reproduce best in warm environments.
Refrigerating or freezing food is a good way to slow micro-organisms’ growth and keep the food fresh for longer.
Refrigerating and freezing won’t kill microorganisms, though; they will reactivate once at a higher temperature.
Enzymes are natural chemicals found in foods.
Many enzymes are responsible for the ripening of fruits, so a green tomato can turn red even after it has been picked.
In the presence of oxygen and moisture, enzymes will eventually cause food to spoil.
The good thing is that enzymes can easily be destroyed by heat. Food preservation methods using heat prevent enzymes from causing food spoilage.
Methods that limit air and water will prevent enzymes from working.
Oxygen is crucial for most microorganisms to survive and reproduce and is also essential for enzyme reactions, so limiting oxygen will preserve foods in these ways.
However, oxygen also causes foods to break down through oxidation.
Foods high in fats and fatty acids are particularly susceptible to oxidation.
Short-chain carbon compounds are formed when the fats come in contact with oxygen. These compounds have very acidic odors and a fishy smell.
Bear in mind that lots of foods have a high fatty acid content.
For example, brown rice spoils much faster than white rice because of its healthy oils.
Pests don’t necessarily cause food spoilage. However, they can get into your food supplies and cause contamination.
For example, a common problem with food stored in Mylar bags is that rats can chew through them. Viruses from the rats’ mouths can then get into the food.
Since the bag is destroyed, the food is now exposed to air, and microorganisms will grow.
Thus, it is crucial for long-term food preservation to choose quality food storage containers.
This is one aspect that a lot of people forget about.
Even if your food is entirely free of moisture and oxygen, it can still be damaged if exposed to light through photodegradation. Some foods, such as fats, proteins, and vitamins, are much more sensitive to photodegradation.
Exposure to light doesn’t necessarily mean the food will be unsafe to eat. However, the food can become discolored and lose much of its vitamin value.
Ways to Preserve Food
To preserve food, you must inhibit the five causes of food spoilage.
The best food preservation methods will protect against multiple causes. No plan is perfect, though, so practices are often combined.
The methods of food preservation can be broken down by:
1. Heat Preservation Methods
Heat kills microorganisms and enzymes, which leads to spoilage. Heat also removes the moisture that they would thrive on.
2. Cold Preservation Methods
Most bacteria thrive in what the USDA calls the “Danger zone” of 40 °F and 140 °F (4.4°C- 60°C)
Keeping microorganisms at a cool temperature reduces how quickly they replicate, and food lasts longer.
- Root cellaring
3. Chemical Methods
Many of the store-bought foods we eat are preserved with chemicals like Benzoates and nitrates.
There are healthier, natural ways to do chemical preservation at home.
- Vinegar pickling
- Lactic acid fermentation
- Salt curing
- Sugar curing
4. Mechanical Methods
These food preservation methods prevent enzyme reactions from occurring and microorganism spoilage. They are usually unsuitable for long-term food storage.
- Vacuum sealing
- Oxygen absorbers
- Filtration and clarification
- Oil and paraffin
Methods of At-Home Food Preservation
There is no one “best’ food preservation method to use.
It is best to combine multiple methods to provide better protection against spoilage.
However, from a “survivalist’s” perspective, we can rule out some methods. Freezing, for example, is susceptible to power outages unless you have a solar freezer.
We’ve chosen to focus on the most popular at-home food preservation methods for these reasons.
It is best to learn several of these, so you have multiple ways to preserve food.
When you go to the supermarket, you find canned foods.
The history of canned foods goes back to the 18th century when Emperor Napoleon of France was worried about keeping his soldiers fed.
Since then, many farmers and homesteaders have stored their crops for the winter by canning.
Once canned, foods can last for more than 5 years.
Methods of Canning
There are several methods of canning. They all rely on ensuring the canning jars are sterilized, and the lids are sealed.
Heat is applied to the food in the clean, sealed jar. The heat kills microorganisms that would cause spoilage and removes air to create a seal.
Water Bath Canning Method
This is the easiest at-home canning method.
You can buy special water bath canners (Amazon Link), but you can also use a large cooking pot with a tight-fitting lid.
The sterilized food jars are submerged in boiling water and cooked for a shorter time at lower temperatures.
This method is suitable for acidic foods such as:
Read our guide to water bath canning.
Pressure Canning Method
This is the safest method for preserving meats and other low-acid foods (including many vegetables).
Compared to the water bath method, the jars are cooked at a much higher temperature of 240 degrees F.
Pressure canners have special lids that trap the steam, which allows them to get up to this temperature. A vent in the lid releases pressure.
Canning in Metal Cans
If you want to preserve foods in a metal can, you’ll need a commercial-grade canning machine that can be used with metal cans.
You’ll also need a special can sealer or seamer.
Until recently, these machines were too pricey for home use. However, prices have decreased drastically, so this is becoming a more affordable option.
Key Takeaways – Canning
Best For: Fresh produce
Shelf Life: 1 to 5 years
- Good for smaller quantities
- Good for garden surplus
- Glass jars can break easily
- Metal canning machines are pricey
- Food quality decreases quickly
Dehydrating preserves food by removing the water from it. Without water, microorganisms and enzymes aren’t able to cause food spoilage.
When combined with vacuum-packing to remove oxygen, dehydration is a great way to preserve food.
On their own, though, dehydrated foods will only last for about a year.
Insect larva loves dried fruits, too, and if you aren’t careful about how you package them, you’ll find insects in your food.
NOTE: Special care needs to be taken with drying meats to make jerky. Meat needs to reach a sufficient temperature to kill bacteria like salmonella.
Home dehydrators are great for people starting with food preservation.
Recommended Reading: Best Food Dehydrators Reviewed
However, they have the serious drawback of not being able to hold much food at once. You’ll need to build a solar dehydrator if you want to dry larger amounts of food without relying on huge amounts of electricity.
For step-by-step instructions and plans, check out the book The Solar Food Dryer: How to Make and Use Your Own Low-Cost, High Performance, Sun-Powered Food Dehydrator. (Amazon Link)
Key Takeaways – Dehydrating
Best For: All Fresh Foods
Shelf Life: 6-12 Months; 5+ years when combined with vacuum sealing
- Cheap and easy
- Can make own dehydrator
- Foods retain nutrients
- Short storage life unless combined with vacuum sealing
- Meat drying can be difficult
Traditional Lacto-fermentation relies on “helpful” lactobacillus bacteria, naturally found in food.
The food is mixed with a brine of salt and water. The salt helps draw sugars out of the food, which the Lacto bacteria then eat, producing lactic acid. Harmful bacteria can’t survive in an anaerobic, acidic environment.
The salt in fermentation also helps lower the oxygen amount, which furthers preservation.
Key Takeaways – Fermenting
Best For: Fresh produce, though many cultures ferment meat and milk.
Shelf Life: Approx 6-12 Months but many report ferments lasting 5+ years.
- Foods retain nutrients
- Source of probiotics
- Preserves vitamin and enzyme levels
Vacuum sealers work by removing air from the food packaging.
Without oxygen, microorganisms cannot grow, slowing enzyme actions and inhibiting oxidation.
All types of foods can be vacuum-sealed.
However, a vacuum sealer won’t remove water, nor will it kill any microorganisms. Thus, to preserve vacuum-sealed foods, they must be frozen, refrigerated, or dehydrated.
You can make your vacuum sealer using Ziplock bags and cheap equipment like tubing and syringes. These DIY vacuum sealers won’t remove all the oxygen from the bag, so they are inferior to quality store-bought vacuum sealers. (Amazon Link)
Key Takeaways – Vacuum Sealing
Best For: Dehydrated Foods.
Shelf Life: 5+ years when dehydrated.
- Very effective when combined with dehydration
- Requires a special machine and bags
Oxygen absorbers are packets containing iron powder, salt, and clay.
The salt and the clay activate the iron, causing it to scavenge oxygen molecules.
The packets are made to allow the oxygen to enter but not exit.
A lot of people confuse oxygen absorbers with vacuum sealing. Both methods preserve food by removing oxygen.
However, oxygen absorbers are better suited for long-term food storage. The vacuum packing bags are relatively thin. Eventually, they will lose their seal and allow oxygen into the pack.
By contrast, the Mylar bags used with oxygen absorbers are designed to keep their seal much longer.
Dehydrated and freeze-dried foods stored in Mylar bags with oxygen absorbers can last for 15+ years.
Key Takeaways – Oxygen Absorbers
Best For: Dehydrated and freeze-dried foods.
Shelf Life: Up to 15 years.
- Can be used for long-term food storage
- Fairly easy
- Can use iron to seal Mylar bags
- Need special Mylar bags
Freeze-drying involves freezing the foods and then drying them with a powerful vacuum.
As the ice melts, it turns to vapor and evaporates.
Once sealed in an oxygen-proof bag, freeze-dried foods are impervious to moisture and oxygen spoilage.
This is how astronaut food is preserved. Even ice cream can be freeze-dried.
Compared to other home food preservation methods, freeze-drying is relatively complicated.
This is not an option for most. However, some prepper groups or homesteaders go in together on the costs, which could make it a viable option.
Because freeze-drying preserves nutrients and taste and is suitable for long-term food storage, it is a worthwhile investment for those serious about food preservation.
Key Takeaways – Freeze Drying
Best For: Fruits and vegetables but all foods (including meats, dairy, and full meals) can be freeze-dried.
Shelf Life: 2 to 20 years, depending on packaging.
- Retains nutrients and flavor
- Suitable for long-term food storage
- Extremely pricey, out of reach for most
- Complicated machinery required
There are several ways to cure food, but they all utilize salt, nitrates, nitrites, or sugar to draw moisture out of the food through osmosis.
Many curing processes also involve smoking.
Smoke curing seals the outer layer of the food, so it is harder for bacteria to enter.
Meat is cured with salt in 4 ways:
- Rubbing salt into the meat
- Packing the meat into salt
- Putting the meat into a salt solution (brine)
- Injecting salt solution into the meat
Sugar curing recipes are usually for bacon, ham, or other pork recipes.
The meats are submerged in a sugar brine and stored at a very cold temperature.
Afterward, the meats can be hung in a smokehouse for further curing.
You’ll need to build a smokehouse to cure meats this way.
It isn’t as hard as most think to smoke cure meat. However, you must be careful to ensure the meat is at the proper temperature.
You don’t want to get food poisoning from bacteria growth!
The USDA recommends smoking at 145° F for 7 hours or 155° F for 4 hours.
If you go over 155° F, the meat will get cooked instead of dried.
Note that recommendations for smoking temperature vary. Some recommend temperatures as low as 125° F for 10 hours.
Key Takeaways – Curing
Best For: Best For: Meats and fish.
Shelf Life: Up to 4 years when stored in a cool, dry place.
- Great for proteins
- Tastes good!
- Curing in brine is simple
- Risk of food poisoning when not done properly
- May need to build a smokehouse
Storing Dry Foods
Foods like dry beans and grains can last for a very long time on their own.
It might seem like no preservation is needed for these at all. Yet, this is not the case.
Dry foods are particularly susceptible to pests like moths.
Even if you store your dry foods in sealed containers, you might still have an infestation.
The reason is that there are already insect eggs in the food when you buy it.
What happens is this: You buy dry foods and put them in a container for storage. The tiny insect eggs in the food start to hatch. Soon, you’ve got larvae munching the food in your containers. You might even see a bunch of moths fly out when you open the container!
To prevent this, you must kill insects’ eggs before you store dry foods.
According to Minnesota State University Extension, putting your bulk foods in the freezer for 4 days will kill any eggs.
You can also microwave dry foods for 5 minutes to kill eggs.
Once you’ve taken this step, most dry foods can last for years inside jars or plastic containers.
If you take the extra step of vacuum sealing them or using oxygen absorbers, many dry foods can last up to 20 years.
See our guide to preventing pests in long-term food storage.
For short-term storage, the choice of storage containers isn’t as important.
Once you start preserving food for extended periods, your food supply mustn’t succumb to pests, humidity, or damage from natural disasters.
Many people store preserved foods in glass jars because they are cheap and can also be found for free. Small jars also make it convenient to rotate through your stockpile.
The benefits stop there, though.
Glass jars are susceptible to breakage, such as if an earthquake were to hit.
They also don’t hold much food. You’d need about 24 jars to hold 50 pounds of rice.
There is also the issue of oxygen damage. Oxygen absorbers should be used when storing dehydrated and freeze-dried foods in glass jars.
Put one or two 100cc oxygen absorbers into a 32-ounce jar and screw on the lid. Within a half-hour, you should hear the lid plink sealed as the air is drawn out of it.
Plastic PETE Containers
A cheap alternative to glass jars is to use PETE (polyethylene terephthalate) plastic bottles.
PETE bottles keep out moisture and air better than other types of plastic bottles. They can even be used with oxygen absorbers.
Many supermarket foods are packaged in PETE bottles. These can be reused for your food storage.
Look under the bottle to see whether it has a PETE or PET symbol.
Often the seal on PETE bottles gets damaged and causes leakage. Make sure your PETE bottles aren’t leaking by:
- Screw the lid on tightly.
- Place the sealed empty bottle underwater
- Press on the bottle
- If air comes out, then the bottle is leaking and shouldn’t be used
Some preppers swear that their food lasts for 10+ years in PETE bottles.
A more realistic estimate is around two years.
Long Term Food Preservation
Standard preservation methods allow food to last approximately one year.
When we talk about long-term food preservation, we talk about food lasting for 5+ years.
Many foods can even last 20+ years when properly preserved and stored.
There is no shortage of companies selling emergency foods with long shelf lives. Buying these food buckets is a fast and easy way of getting prepped.
Compared to junky non-perishable supermarket foods, the cost of emergency food in buckets is quite reasonable.
If you choose to make your own long-term food stockpile, the cost is lower, and you’ll have many more options available.
Foods Not Suitable for Long Term Storage
Emergency food companies sell virtually all kinds of food. However, those companies have access to very advanced machinery.
You might not be able to preserve the same foods at home safely.
Foods containing oils, fatty acids, or moisture are unsuitable for long-term preservation.
For example, dehydrated fruits and vegetables must be dried to the point that they snap when broken. If they are still chewy, then the moisture in them will cause them to spoil eventually.
Another example of unsuitable food is brown rice. While white rice is perfectly suitable for long-term storage, brown rice contains too many fatty acids, which will cause it to spoil.
The following foods are NOT suitable for long term storage:
- Barley, pearled
- Dried eggs
- Dried meat
- Whole wheat flour
- Brown rice
- Milled grains
- Brown sugar
The most accepted long-term food storage method is putting dehydrated or freeze-dried foods into a Mylar bag with oxygen absorbers and then putting them into a bucket.
Mylar bags are made from polyester resin.
The material has revolutionized food storage because it is durable, lightweight, and doesn’t allow air or moisture.
When choosing Mylar bags, make sure you pay attention to the thickness. A thickness of at least 5.4 mils is recommended.
The bags should have an aluminum core and be FDA/USDA food safe.
How Much Food Per Bag?
I prefer packing food in smaller Mylar bags.
If I need to open a bag to use the food, I’d rather it be five pounds of rice instead of 50lbs.
Standard Mylar bags hold one gallon of food.
The weight per gallon varies depending on the food.
The following gives you an idea of how many pounds of food will fit in a one-gallon mylar bag.
Pounds Per Gallon
- Rolled Oats: 4.17 pounds
- Wheat: 7 pounds
- White rice: 6.8 pounds
- Dry milk: 5 pounds
- Beans: 7 pounds
- Dried onions: 3 pounds
- Dried apple slices: 1.67 pounds
How to Seal Mylar Bags
If you can afford it, buy an impulse sealer for your Mylar bags. This is the surest way to get an adequate seal.
Many people get by using hair straighteners for sealing their Mylar food bags, though. You just have to be careful that you’ve made a complete seal.
This can be difficult with powdery products (such as dried milk) because they can get into the seal.
Watch the video below for a demo.
Before sealing your Mylar bags, you will need to throw in some oxygen absorbers.
These will remove oxygen from the bag, creating an anaerobic environment to keep food safe.
Oxygen absorbers are rated in cc’s depending on how much oxygen they can absorb.
The number of absorbers you need will depend on their rating, the container’s size, and how much oxygen is in the container.
For example, bulky products like dried apple slices will have more air than small products like rice.
Because of this, the following suggestions for how many oxygen absorbers are only guidelines.
If you think your container has a lot of oxygen in it, you’ll need more absorbers.
Working with Oxygen Absorbers
The moment you take the oxygen absorbers out of their packaging, they will start absorbing oxygen. So, you need to work quickly!
You’ll be able to tell they are working because they’ll feel warm.
An oxygen absorber usually takes approximately four hours to reach its maximum absorption. After that, they will be useless for preserving food.
Have a mason jar nearby if you aren’t using all of the oxygen absorbers in your pack.
Choose the smallest jar that will fit all of the unused oxygen absorbers.
Take out the oxygen absorbers you need and put the rest into the jar immediately.
Note: Don’t use oxygen absorbers with sugar or salt. You’ll end up with a rock-hard block that requires a pickaxe to break up.
Once your food is safely packed and sealed into Mylar bags with oxygen absorbers, the final step is to put the bags into a bucket.
The bucket is crucial for long-term food preservation because it protects against the elements and pests.
Some people put dry foods (such as dry beans and lentils) directly into a bucket with oxygen absorbers, skipping the Mylar bag. This is NOT an acceptable method of long-term food preservation!
The seal will eventually break and allow air in. If you’ve skipped the Mylar bags, you’ll also have trouble using food from your buckets.
Imagine that you open up a 5-gallon bucket of rice during a hurricane. That’s about 35 pounds of rice! You won’t be able to seal up the bucket again, and all that extra rice will go to waste.
For these reasons, it is essential that you put foods first into smaller Mylar bags and then into buckets.
Gamma Seal Lids
If you want to use some of the food from your buckets regularly, it is worth paying a bit extra for gamma seal lids.
This system makes it easy to access the food but creates an air-tight seal when closed.
These lids have special gaskets that go on the outer part of the bucket. There is a smaller lid that twists into it.
If you don’t invest in these lids, at least make sure you buy a bucket opener.
That $5 tool will save you a lot of grief when you need to open your buckets!
Long Term Shelf Lives of Food
When adequately dried and stored in Mylar bags with oxygen absorbers, foods can last a long time.
Here are some estimates on the shelf life of foods preserved this way.
|Hard Grains (corn, wheat, millet, flax)||15 to 20 years|
|Soft Grains (rolled oats, oat groats, barley, quinoa)||8 years|
|White rice||8 to 10 years|
|Brown rice||1 to 2 years|
|Beans||8 to 10 years|
|Dehydrated Vegetables||8 to 10 years|
|Dehydrated Fruit||10 to 15 years|
|Dried milk||5 to 10 years|
|Dried eggs||5 to 10 years|
|Pastas||10 to 15 years|
|Garden seeds||2 to 10 years|
|Sugar, honey, salt, molasses||Indefinite|