As soon as you have acquired dry foods for long-term storage, there are enemies that are working against you. If left unchecked, these enemies will steal nutrients and flavor, make your food taste foul, or render it entirely inedible. Don’t let the enemies of food storage win! Proper packaging and storage methods can prevent these problems from ruining your efforts and your food. The last thing you want after investing time and money into food storage is to have it inedible when you need it.
In order to properly avoid the enemies of food storage, it’s important to know what they are.
Ideally, your food in long-term storage will be stored at temperatures between 50°F and 60°F (10°C and 16°C). Heat causes food quality, taste, and nutritional value to decline. A basement, crawl space, or root cellar all work well for keeping temperatures down. Be aware of possible moisture problems if using a crawl space or root cellar. In the absence of a basement, choose the coolest spot you can for your food storage. If you can’t get a room down to 60°F (16°C), get it as cool as you can. Even 75°F (24°C) is better than 90°F (32°C). Plug heating ducts to the storage area if possible to keep it cool in the winter.
Exposing food storage to light can cause deterioration of flavor, appearance, and nutrition. Sunlight compounds the problems by adding the effects of heat as well. Keep your food in opaque containers if possible. Containers that light can permeate, like PETE bottles, glass jars, and some buckets, should be stored in a dark room or covered to reduce light exposure.
Oxygen in contact with food causes oxidation, leading to flavor loss, discoloration, odor, and rancidity. The air we breathe is 20.95 percent oxygen. The ideal oxygen level for food storage is less than 1 percent. Using oxygen absorbers in airtight food storage containers can reduce the oxygen level to 0.1 percent or lower.
Dried foods need a low moisture content to store well. Moisture aids the growth of bacteria and mold. Foods should always be stored in airtight containers that keep moisture out, especially in humid environments. Exterior sources of moisture, like direct contact with water, can cause rusting on some food storage cans, eventually making the food in them inedible. Storing cans directly on concrete or other cold flooring can occasionally result in condensation buildup on the bottom side of the can. Food should always be stored so there is insulation between a hard floor and the food container.
Pests include rodents, insects in all their stages, and any other living thing that wants to eat your food. You didn’t buy your food to feed pests, so take measures to keep them out of it. Keep food in containers that protect it from rodents or insects chewing through. Properly treat your bulk foods for possible insect egg or larva infestation prior to storage (see the Eliminating Insects From Dried Foods sidebar in this chapter).
Insects, larvae, and eggs can be present in bulk foods before you purchase them. If the food is not treated to eliminate these pests, they can hatch and grow, feeding on your food and leaving a mess in their wake. Protect your food from insect infestation using one of these methods:
Properly used, oxygen absorbers reduce the amount of oxygen in a container to 0.1 percent or less. This is insufficient oxygen for adult or larval insects and insect eggs, and they will be eradicated within fourteen days of sealing. Because oxygen absorbers are also the most reliable method of reducing oxygen in a container, by using them for insect control you are taking care of two problems at once.
Dry ice is frozen carbon dioxide. Dry ice treatment is not recommended for removing oxygen for long-term storage, but it has been shown to be effective in eliminating adult insects and larvae. However, fumigating your food with dry ice isn’t fully effective against eggs. To fumigate with dry ice, place 3 to 4 inches (8 to 10cm) of grain or other dried food at the bottom of a 5-gallon bucket. Add about 2 ounces of crushed dry ice, and cover with the remaining food. Put the lid on loosely and wait for the dry ice to fully evaporate (around thirty minutes).
Freeze 1 to 15 pounds (1⁄2 to 7kg) of food, double bagged in plastic, for two to three days. Freezing kills adult and larval insects but is not guaranteed effective against eggs. Thaw thoroughly and make sure the food is moisture free before storing it.
Diatomaceous earth (DE) is a natural insecticide consisting of fossilized remains of diatoms, a hard-shelled algae. Under a microscope the fine powder looks like shards of glass. It does not harm humans, so is safe to ingest, but it will damage insects that come in contact with it so they die of desiccation (drying out). A small amount of DE mixed in with your dry food or placed in the bottom of a bucket will kill the insects that contact or ingest it. There is a lot of room for error with this method, as the insect actually has to contact the DE to be affected by it, so I would recommend another method of insect control in addition to or instead of using DE.
Handling of food products is especially problematic with containers that are easily cracked or compromised. Glass jars break, plastics can crack, Mylar bags can develop pinhole leaks or tears, bucket seams and seals can leak, and even #10 cans can develop air leaks through rough handling.
Time is a food storage enemy we have little control over. It marches on regardless of how we try to slow it down. The best way to prevent food spoilage due to time is to rotate your storage foods, using the oldest foods first. This ensures that the foods you have stored will always be the freshest they can be.
Oxygen absorbers are small packets filled primarily with iron powder developed for reducing oxygen in a food storage package. When exposed to air, the iron in the packet oxidizes, using the oxygen in the atmosphere to chemically change to iron oxide (rust). When an oxygen absorber is working, the oxidation creates heat and the packet gets hot to the touch.
Oxygen absorbers are available in various sizes, each capable of absorbing a specified volume of oxygen, listed in cubic centimeters (cc). The size of oxygen absorber needed depends on the food you are storing and the size of container it is being stored in. Oxygen absorbers use oxygen from the void air space in a container. This is the space between the food particles. Foods like macaroni will have more void air space in a full container than foods like flour. There is some fancy math to figure out exactly how much oxygen is in a container of food and from there determine which size oxygen absorber to use. It is not as simple as it may seem—cubic centimeters, which is a measure of volume, does not convert neatly from a measure of weight like pounds without more information, like knowing the specific densities of each food you want to pack. Thankfully, there has been enough research on oxygen absorbers and food storage that instead of getting into advanced math, I can provide a simple table for reference. Combine oxygen absorbers if necessary to achieve the volume of absorption needed in your food container. For example, five 100 cc absorbers will do the same job as one 500 cc absorber.
After being exposed to the air, oxygen absorbers are only viable for a limited amount of time. Oxygen absorbers are best used within thirty to sixty minutes of opening. You want as much of the iron powder to oxidize while sealed in your container as possible. Leave the oxygen absorbers in their original packaging until you are ready to use them. Fill all your containers, then open the package of oxygen absorbers, insert them into the containers, and seal the food storage container as quickly as possible. Any oxygen absorbers you will not use quickly need to be repackaged in an airtight container to stop oxidation and keep them good for later use. You can seal them into a vacuum sealer bag (like FoodSaver), Mylar bag, or tightly into a small canning jar with a tight-fitting lid, and they will be ready to use the next time you need to seal something. For convenience, repackage large quantities of oxygen absorbers into smaller packs using either a vacuum sealer bag or a Mylar bag.
Oxygen absorbers
Holding almost 1 gallon of food, #10 cans are one of these best ways to package and store dry foods.
In order to pack your food in a #10 can, you will need access to new cans and lids, oxygen absorbers, and a dry pack can sealer. Empty cans are lightweight, but having them shipped is costly due to their size and fragility when empty. The cost decreases if you can purchase a full pallet load. Dry pack can sealers start at around eight hundred dollars for a hand-crank version and thirteen hundred dollars for a motorized canner. If you want to purchase a can sealer and cans, it may be something you want to invest in with a few friends or relatives to reduce the cost.
Food sealed in a #10 can
Some dry foods may be stored in vacuum sealer bags like FoodSaver bags. These bags are thin and clear, so they do not protect your food from light or most pests, and won’t work if your product has any sharp edges, like pasta. Even if your food will not puncture the bag, it will need to be stored inside a barrel or bucket to protect the fragility of the bag and keep light out. Vacuum sealer bags are better used for foods stored in your freezer than for long-term storage.
FoodSaver vacuum sealer
Freeze-dried peas sealed in a vacuum sealer bag
Mylar is a brand name of metallized plastic pouches that are commonly used for long-term food storage. They are usually silver in color, but can come coated with other colors as well.
Food sealed in a Mylar bag, two empty Mylar bags of different sizes
Mylar bags are available in a variety of thicknesses, most ranging from 3.5 mil to 7 mil. A mil is one thousandth of an inch, so it’s pretty thin, but there is quite a difference between 3.5 mil bags and 7 mil bags. The 3.5 mil bags are very thin and flexible—about the thickness of a potato chip bag. The 7 mil bags are much sturdier and less flexible. With the thinner bags, under 4.5 mil, there can be some light permeation. Thinner bags are also prone to being punctured by the foods being packaged or through rough handling. I recommend 4.5 mil or higher thickness for long-term food storage.
Many foods from the grocery store are packaged in Mylar bags that can be reused if they are opened carefully and washed out. You will find Mylar packaging primarily on snack foods like potato chips, cookies, or lining boxes of crackers or other snacks. These bags are thin, usually under the 4.5 mil recommended to use for food in long-term storage, so if you are going to use them, stick to soft foods like flour, and store the filled bags inside a bucket or other container to protect from light, abuse, and pests.
A few styles of Mylar bags are available with zip-seal tops. These bags still need to be sealed with a heat sealer above the zipper to ensure an airtight seal for storage. Use the zip seal to open and reseal the bag after it has been cut open for use.
Mylar bags can be reused after they are emptied. Just wash them out, let them thoroughly dry, and they’re ready to fill and seal again. If you plan to reuse bags, you’ll get the best results by cutting the bag open just under the seal and then resealing the bag as close to the top as possible. Give your bags a thorough check for holes or tears prior to reusing them.
Sizes of Mylar bags range from 5 gallon to small enough for a packet of seeds. If you can’t find the size you need, you can always make your own custom-sized bags from larger bags. Use scissors to cut the large bag to the size you want and seal the open edges, leaving one side open for filling.
Commercial impulse sealer: Impulse sealers are made specifically for sealing Mylar bags. They are available in a variety of sizes and styles and are available for as low as fifty dollars for a 12-inch (30cm) sealer. These sealers are easy to use, and the amount of heat they generate is perfect for sealing Mylar bags.
Vacuum sealer with heat strip: The heat strip that seals vacuum sealer bags can be used to seal Mylar as well. If your sealing strip is thin, you may want to seal it two or three times slightly offset to make sure the seal is sufficient for the pressure created by the oxygen absorber.
Clothing iron: To use a clothing iron, set your iron to the cotton or high setting and turn the steam off. In order to have the pressure necessary to seal the bag, you’ll need something rigid underneath the bag you’re ironing. For sealing edges on a newly cut, empty bag, the top of your ironing board covered with a clean cloth will work for support. Once the bag is full, you won’t be able to lay it down without spilling the contents, so use a thin board or metal bar that can be laid across the open end of the bag at least 1⁄2 inch (13mm) in from the edge. Fold the top of the bag over the support and iron it closed.
Hair straightener: Good for more than just style, hair straighteners are an inexpensive and easy way to get Mylar bags sealed. These hair-styling tools have two flat hot plates that clamp together and can be bought new for as little as ten dollars. They aren’t very long, so you may need to press to seal more than once across the top of the bag. If you’re buying a hair straightener just for sealing bags, the straighteners with thinner plates are sufficiently wide.
Plastic HDPE (high-density polyethylene) buckets are available in sizes from 2 gallons to 6 gallons, either round or square, and are a great method of storing bulk foods.
When storing food in buckets, start with buckets that are clean, food grade, and have never stored products other than foods (like paint or oil). Food-grade buckets will have recycle code 2, but not all HDPE buckets with code 2 are food grade. Purchase new buckets that are labeled as food-grade buckets, or buy used buckets that have been used only for storing food. If in doubt about whether a bucket is food grade, assume it is not and use it for a nonfood purpose. Buckets can be obtained for around seven dollars new or can be found used at locations like bakeries and restaurants for little or no cost. Make sure any bucket you are going to use for storing food has a good sealing lid with it. This may mean buying new lids for the used buckets if their lids don’t seal well or are missing the gasket.
The instructions on a Gamma Seal lid advise using a rubber mallet to attach the outer ring to an empty bucket. Once that ring is snapped on, screw the inner ring into the outer ring and your bucket is sealed.
If this method does not work for you or if you just want to skip to the easy way to get the lid on, follow these steps instead:
Gamma Seal lid on a bucket
Bucket opener tool
Standard bucket lids snap onto the bucket top and need to be pried off one wing at a time when you want to open the bucket. A rubber mallet can be used to seal and reseal the lid on the bucket, or you can stand on the lid and stomp around the edges to snap it on (with shoes on, of course!). Using a bucket opener tool makes removing the lids much easier than trying to take them off with your fingers. Bucket opener tools can be purchased at food storage retailers and are well worth the three-dollar price tag if you have any of your food storage in buckets.
An alternative to a standard bucket lid is a Gamma Seal lid. These can be useful if you plan on opening a specific bucket and closing it back up often. The Gamma Seal lid is a two-part lid consisting of an outer ring that snaps onto the bucket and an inner lid that screws into the outer ring—no stomping or mallet required to reseal the lid. These lids cost more than a standard lid, so if you have a lot of buckets, you may want to put them only on the buckets you’ll be accessing the most. Once a Gamma Seal lid is installed on a bucket, it does not come off. But you can always refill the bucket and continue using the lid.
Buckets are made of HDPE plastic. This plastic is porous, although microscopically so, and over time gas can permeate your bucket. Some buckets are also slightly translucent, allowing light to penetrate to the food stored inside. For extra protection from permeability and light, or to use a nonfood-grade bucket for storing food, line the bucket with a large Mylar bag before filling it with food. The Mylar gives an extra layer of protection from air and light as well as keeps your food together if your bucket is broken for any reason.
Buckets are a very versatile container for more preparedness purposes than just storing food.
Dry foods can be sealed in canning jars for long-term storage using either an oxygen absorber or a vacuum sealer with a jar lid sealing attachment. Do not use the vacuum sealer attachment to seal wet foods in jars—always use approved canning techniques as outlined in chapter five of this book.
Vacuum sealing foods in jars does not have to end with rice and beans. Removing the oxygen from the atmosphere inside the jar will prevent oxidation and rancidity in a variety of foods. Try sealing these foods in jars with an oxygen absorber or vacuum sealer to increase their shelf life:
FoodSaver jar sealer attachment
Food stored in reused PETE plastic containers
Many foods that can be purchased at the store are packaged in PETE plastic containers. This plastic has recycle code 1 and is stamped with the letters PETE or PET next to the code. Most of these containers are clear or translucent, so store them away from light to better protect the foods in them. Once a PETE container is emptied of its original contents, wash it out and allow it to thoroughly dry before storing food in it.
Your long-term storage may use a variety of these storage methods, depending on the food being stored and the resources available to you. Proper packaging and storage of your food will protect it from the enemies of food storage and ensure your food is as nutritious and great tasting as possible when you need to eat it.