A mylar bag is excellent for long term food storage, including long term storage of flour and sugar.
The key is keeping them in a cool, dark place and sealed tight.
A plastic storage container with a tight lid is ideal, but a large Ziploc bag is totally fine, too. The impermeable container will keep out pests as well as moisture. Most people find it easiest to keep flour in the pantry. Avoid warm, sunny spots.
Storing flour in airtight plasticware or a glass mason jar will keep it fresh for up to 10 months and keep pests like flour bugs at bay. If you have the tools to vacuum seal your flour, it can last for up to two years.
You can easily store up to 2kg of flour in a 5L plastic container. They are also stackable which ensures they are easy to store in your pantry and use your space effectively. Plastic containers can be better than glass because it eliminates the risk of shattering in the freezer or from being dropped.
You can leave your flour in its original bag, but for long-term storage, it's best to move it to an air-tight container that can protect against smells (flour will absorb odors) and liquids from the freezer walls.
The best way to store flour is in an airtight storage container in a dry place and in a dark place, such as a pantry. This will prevent the flour from light exposure, which can cause oxidation and an increase in heat. You can also store flour in a ceramic or stoneware container.
Store sugar in a cool, dry location (not the refrigerator). Moisture makes granulated sugar hard and lumpy. Once this happens, it creates problems in usage and there is no easy method to restore lumpy sugar. Always store all sugars in an odor free area.
Flour and sugar, for example, may last up to six months in the pantry, but storing them with a vacuum sealer increases that range to about one to two years. Rice and pasta may have the same results — both may last up to six months when conventionally stored, but that number jumps to one to two years when vacuum sealed.
Adding whole bay leaves and garlic cloves to the area seems to deter flour bugs from setting up shop in your pantry. Garlic may leave a trace flavor in your baked goods, so if you don't want that, go for the bay leaves instead.
Glass jars are a surprisingly good container for packaging dry goods such as; wheat, white rice, rolled oats, sugar, salt, and corn in your long term food storage. The great advantage of using glass is that it creates a true oxygen and moisture barrier. Also, glass does not leach toxins into the food.
White Flour
Whether your container is glass or plastic is up to you—just make sure the lid is closed tightly. Store the container in a cool, dry, and dark spot like a cupboard or pantry for up to one year.
The best temperature to store grains, including rice, is 40°F or below; however, rice stored at a constant 70° F with oxygen absorbers will store well for up to 10 years. In cooler storage areas rice sealed in oxygen-free containers can be stored for up to 30 years.
Flour. Like sugar, you want to keep pests out of your flour supply, so storing flour in airtight containers is also a good idea. I keep most of my flour stored at room temperature, but an exception is whole wheat flour, which I try to store in the freezer because of how infrequently I use it.
All-purpose flour is most commonly used and accessible flour in the United States. It can be kept for up to 8 months if stored in a sealed container, in a cool, dark place where it is safe from infestation and spoilage. If you choose to store it in the refrigerator, it can last up to an entire year.
Can I Use Oxygen Absorbers with Sugar? Do NOT use oxygen absorbers with sugar. Sugar doesn't go bad, so there is no reason to use oxygen absorbers: it won't help the sugar last any longer. Further, oxygen absorbers will turn the sugar into a rock-hard clump.
You will achieve the longest quality shelf life by storing white flour in an air-tight container (#10 can, Mylar bag, mason jar, or PETE plastic bottle) with an oxygen absorber. The oxygen absorber extends the quality of the life of the flour and prevents any insects from surviving in storage.
It is a source of calories that can be important when food is scarce. The primary reason for storing large amounts of sugar in your food storage is to make comfort foods, provide calories, and for use as a preservative in fruits, jams, jellies, and sweet sauces.
Glass container: Glass containers are another good option as long as you seal them with a plastic lid. The container inside a container: You can also store salt in its original packaging but inside another container. You can use a plastic lid to seal the container and keep the moisture out.
Shelf Life: 10+ years
By sealing flour in Mylar bags with oxygen absorbers, the flour is completely safe from light, moisture and oxygen. Even insect eggs can't hatch because there isn't oxygen in the packaging. When stored this way, white flour can last 10-15 years.
How many oxygen absorbers do I use? With 100cc oxygen absorbers, you use about 2 per gallon when storing Grains, Flours, or Rice. You use about 4 per gallon when storing Pasta and Beans.