03/24/2021
Great article found in "Grit Magazine"
Which Foods Can Be Dry Canned?
In a nutshell, "dry-pack canning" is used for foods that have less than 10 percent moisture and are low in oil content. Foods like nuts that contain oils go rancid if kept for long periods of time. Foods such as pasta, cereal, white rice, white flour (unlike brown rice or flour, which contain oils), beans, corn, powdered milk and eggs, herbs and spices and other dried foods are excellent choices for dry canning.
Oxidation is what causes foods to spoil, thus removing oxygen from foods will let them retain their freshness and food quality for long periods of time. Air itself is 78 percent nitrogen, 21 percent oxygen and one percent other gases. Nitrogen does not cause food to spoil.
There are basically three methods of dry canning: oven canning, canning with oxygen absorbers, and food saver jar sealers. It was the oven canning video that caught my attention although that is considered not the safest route to go. Here is what all three entail.
Oven Canning
Not 100% safe. This method has been around since the 1940s and many “seasoned” home canners swear by this method even though the USDA now deems it unsafe due to it not sealing out all the moisture and botulism can contaminate the food. Another risk is that Mason jars are not made to withstand high temperatures without any liquid and can break or explode when placed in these temperatures for extended periods of time.
Process. It is basically a simple process. First, all jars must be washed and sterilized and thoroughly dry. Then, they are filled with the dry ingredients, leaving a half inch of headspace. Place all jars on a baking sheet and put in an oven that is preheating to 200*. It is important that jars be placed in the oven during the preheating stage to avoid cracking.
Cooling and use. After the oven temperature reaches 200 degrees Fahrenheit, leave them in there for one hour. Then remove one jar at a time, place the lid on and tighten the ring, setting the jar on a towel to cool. As they cool, the lids should “pop” just like they do when regular canning. However, even though the lids may seal, if there is too much moisture left in the jars, they may be unsafe to consume because of mold or botulism growth.
Mason Jars with Oxygen Absorbers
This is by far the safest and easiest method of dry canning. Oxygen absorbers are little packages containing iron powder. When put in airtight containers, oxygen molecules “stick” to the iron. These little packets can reduce the amount of oxygen in containers to less than .01 percent, which is considered safe.
To use, simply put the dry food in a Mason jar or Mylar bag and place the oxygen absorbers on top of the food and seal with lids and rings. It takes approximately 30 minutes for them to absorb the moisture and for the lid to seal. These can also be used with food-grade 5-gallon buckets to store large quantities of food. The thing to remember here is that after the bucket is opened, what food you don’t use must be placed in smaller containers and preserved all over again, because you have let oxygen back in.
Quick transfer. The biggest thing to remember when using oxygen absorbers is to make sure that they are not exposed to the air for any length of time, because they will start absorbing oxygen from the air, rendering them expired in the jars.
Amount. Use enough of them for the amount of food you are preserving. The best rule of thumb is to use enough absorption to deoxygenate the entire empty jar. Usually, 100 cc’s are recommended for pints and 200 cc’s for quarts.
Above all, make sure that they are still good before you use them or your food and time will be wasted. Remember that after the package is opened, they are all exposed. When held in your hand, if they feel like the powder is loose inside them, then they are not expired.
Food-Saving Jar Sealer
The third method is using a Mason jar attachment with your food-saver machine. It seals jar lids to create a vacuum seal that locks air out. This method is considered safe and you do not need oxygen absorbers. If you already have a vacuum sealer, this may be the way to go.
Dry canning does have its advantages and also its drawbacks. On the plus side, you can take advantage of bulk discounts and put away large quantities of dry foods for emergencies and reduce trips to the store. Even though it frees up freezer space, it still requires quite a bit of space elsewhere to store jars and food grade buckets. For example, it takes 24 quart jars to store 50 pounds of rice.
