Rice is easy to prepare and doesn’t need a large space for storage, making it a great addition to your emergency food stack. Some varieties last longer than the others. But, as long as you store them properly, most can last for about five years to over a decade.
The degradation of rice quality is often caused by elevated temperature, moisture and oxygen attack, and pest infestation. To extend its shelf life, you must aim to eliminate these factors by using food-grade containers, oxygen absorbers, mylar bags, and fumigation methods.
This article will explore the factors affecting the shelf life of rice and introduce methods to keep it fresh over an extended period.
Why Should You Store Rice?
Rice is filled with nutrients and minerals essential during emergencies. It has a high-calorie content that serves as fuel to the body, supplying it with the energy it needs to function effectively.
It does not take too much storage space; you can just keep it in airtight containers and bags. It is inexpensive, and you can buy it in bulk to save a few more dollars.
Rice is very easy to prepare and highly satiating, making it an ideal emergency food. You don’t need any special ingredients to prepare it. All you need to do is add water, then heat it, and it’s done and ready to eat.
It is generally safe for everyone. In fact, rice allergy is very rare, and none of the rice’s constituents are listed as a common allergen.
Factors Affecting the Shelf Life of Rice
Rice, having the same variety, bought from the same market and taken from the same bag of rice, may last for different periods if stored under different conditions.
Several factors influence the shelf life of rice. Depending on how well you monitor and control these factors, the rice may last for a few years to more than three decades.
One major contributing factor to the shelf life of rice and other grain products is temperature. It directly affects the preservation of nutrients and pest growth prevention. Generally, a low temperature is ideal – but not too low to reach freezing point (at 32°F).
Your goal is to keep the storage temperature at 70°F or lower. This temperature range slows down the degradation of rice quality and promotes longer retention of minerals and nutrients. However, you should not lower the temperature too much or beyond freezing point. It is expensive to do so, and it doesn’t really change the shelf life of rice significantly.
According to the USDA guideline, a 10-degree Fahrenheit drop in storage temperature doubles the shelf life of dry goods (e.g., rice). The opposite is also true – a 10°F increase in temperature will cut the shelf life of rice by half.
This effect is mainly due to the respiratory activity and degradation of enzymes within individual rice grains. At lower temperatures, the rate of internal water loss is lower, and the growth rate of decay-promoting organisms is inhibited.
Aside from quality preservation, a lower temperature also prevents pest infestation. Most pests and insects found in rice are incapable of growing and developing at low temperatures. They only reproduce at elevated temperatures, so keeping the storage cool will prevent infestation.
Moisture and Humidity
There are two possible sources of moisture that affects the quality of rice during storage: first is the moisture content of the rice itself, and second, moisture from the environment.
The moisture content of rice pertains to the actual percentage of water in it. The lesser its moisture content is, the longer it can last. Although you do not have control over this, it is important to know that the commonly sold white rice has a 14% moisture content. If you can find other brands that advertise a lower moisture content, then you should pick them.
The second source, and the one which directly affects rice quality, is the surrounding air. Air has a characteristic known as humidity. Humidity tells you how much water the air carries. You would want to avoid a high humidity level on your rice storage since this will have a negative impact on the rice quality. Ideally, the humidity level should be 15 percent or less.
The water in the air condenses when there is a significant temperature difference between the air and a surface. The temperature inside the rice container is higher than the surrounding temperature. If the outside air manages to enter the container, there’s a high chance that moisture will condense on the top layer of the rice.
For the same reason, temperature fluctuation inside the storage room must be minimized to prevent increasing the temperature difference between the surfaces of the food containers and the surrounding air.
Moisture inside and on the sides of the container is unwanted since it facilitates mold formation and growth that significantly shortens the shelf life of rice. Moisture also promotes the growth of insects and pests that hastens the degradation of the rice, making it inedible.
Oxygen and Sunlight
Oxygen is vital for all life forms. It facilitates the growth of insects and molds, so you should avoid leaving your rice container open.
You should also avoid exposing your rice storage under direct sunlight. It hastens the loss of the rice’s nutritional value, particularly fat-soluble vitamins, including vitamins A, D, and K. Also, direct exposure to sunlight increases the temperature, which is another effect that you would want to avoid.
Insects and Bugs
Insects, particularly rice bugs or weevils, can destroy the quality of rice quickly. Most of the time, they are not visible when you buy the rice because the bugs themselves are not present; however, their eggs are there.
These eggs will hatch, grow, and reproduce when ideal conditions are met, resulting in an instant infestation problem. All they need to survive is a slightly elevated temperature, oxygen supply and a small amount of moisture from the air.
Surprisingly, rice bugs are safe to eat, and they even provide some extra nutrients. However, the idea of eating insects is gross and unthinkable for most people. With proper methods, you can easily remove these bugs, so there’s no need to throw the rice right away if the infestation is only mild.
Most varieties of rice are good for long term storage; for example, wild rice, arborio rice, jasmine rice, and basmati rice. Most of them can last for at least four years to more than a decade when stored properly.
On the other hand, brown rice is not suitable for long-term storage. Brown rice is known for its superior health benefits. However, due to its unremoved bran layer and high oil content, it can only last for about two years or a year or even lesser. If you are planning to store rice indefinitely, you should pick other varieties instead.
Effective Ways of Storing Rice
Dry Ice Fumigation
Fumigation eliminates all adult insects and their larva present in the rice container. It can be done using dry ice, which is basically the solid form of carbon dioxide.
To fumigate the stored rice, spread an inch thick layer of dry ice on top of a rice layer 3 to 4 inches deep in the bottom of the container, then pour the remaining rice into the container.
The fumes of the dry ice are slightly heavier than air, thus displacing the air inside the container. It would take about 30 to 60 minutes for the dry ice to completely sublimate or turn into gaseous carbon dioxide. Wait for about this long before placing back the lid of the container.
Ensure that all the dry ice has sublimated before sealing or closing the container. A pressure build-up inside the container may occur if it was closed too soon. When this happens, the container may bulge slightly. In this case, do not remove the lid at once; remove it slowly to allow the pressure inside to gradually balance out with the pressure outside.
You may do this method only once – before storage. However, if there are clear signs of infestation due to the eggs that survived the previous fumigation, you may repeat this process.
Deep Freeze Method
This method is done prior to storage and is only applicable to small quantities of rice, about one to ten pounds.
Place the rice in food-grade plastic bags and deep freeze them for two to three days. Most insects cannot tolerate extremely low temperatures, thus eliminating them. Usually, it is effective at destroying insects at all stages, which ensures a longer shelf life.
After freezing, let the rice thaw, and wait for the excess moisture to vaporize completely. Then, if you don’t see any insects crawling on the rice, transfer it to a proper container, then place it in a cool and dry place. Otherwise, repeat the process one more time to eliminate the remaining bugs.
Use Proper Containers
Only use food-grade containers when storing rice, or any food for that matter. These containers are designed to prevent unsafe chemicals from transferring from the container to the food itself. Avoid using garbage bags, fiber barrels, and paint cans to store foods.
Chemical contamination will make the rice unsafe for human consumption. Therefore, if you intend to store rice and keep it fresh for a long time, you should use containers designed to safely store foods.
The best containers for rice for long-term storage are food-grade plastic buckets with lids. They are fairly common in the market, so it is easy to find one of them. These plastic buckets are BPA-free, so their safety is guaranteed.
These buckets are also strong enough; thus, you can stack them to save some space in your storage area. They are also leak-free, so if you accidentally left one on a floor flooded with a few inches deep of water, the contents will remain dry.
You can also place oxygen absorbers inside these containers to prolong further the shelf life of the rice. Over time, air may eventually begin to leak. Adding oxygen absorbers will ensure that the oxygen level inside the containers is kept at a minimum.
Oxygen absorbers are small packets of materials that react with oxygen. Usually, they contain vitamin C and iron minerals that “grab” oxygen from the air by reacting with it. In addition, they also absorb moisture from the air, thus preventing mold formation and growth.
Air contains about 21 percent oxygen, 79 percent nitrogen, and less than 1 percent some other gases in very small traces. By absorbing the oxygen from the air, the molds cannot grow, and the eggs of rice bugs cannot hatch either, thus preventing infestation. The remaining nitrogen is generally inert, meaning it won’t do anything. Insects and molds cannot use this to grow and develop.
To compute the amount of oxygen absorber that you will need, first calculate the 21% percent of the volume of the container that you’ll use to determine the amount of oxygen it contains. Then, from there, estimate the corresponding amount of oxygen absorbers that can cover the total amount of oxygen.
You can also watch this video for your reference.
Mylar bags consist of layers of metallic foils that protect the rice, or any food they contain, against deterioration due to sunlight, oxidation, and bugs.
These bags are easy to use and are effective at preserving the quality of dried goods. When used with oxygen absorbers, they offer the longest rice shelf life, which is about 30 years or longer. They are available in a wide range of sizes: from small bags that can only contain a few garden seeds up to large bags that have the same storage capacity as a five-gallon bucket.
For small amounts of rice, you can store them in a freezer. The very low temperature will not allow the hatching of the rice bugs’ eggs, and it will also inhibit the growth of molds. This method is excellent under normal circumstances. However, it may backfire during an emergency if the power suddenly goes out. Condensation will quickly occur, and the rice will absorb the moisture, causing it to spoil faster.
Signs that the Rice is No Longer Safe for Consumption
Most varieties of rice, especially white rice, are suitable for long-term storage. But, due to the factors mentioned above, their quality may degrade over time and become unfit for human consumption.
Severe infestation by rice bugs or rice weevils is the most obvious sign that the rice has gone bad. You may still resolve mild bug infestation using dry ice fumigation or with heat treatment. However, if the number of bugs has grown beyond control, it is best to discard the rice right away.
When you detect an insect infestation in one of your storages, you should inspect the other containers to check for possible infestation. This way, you can deal with it early on and prevent bug infestation from damaging more food.
For brown rice, the signs that it has gone bad are more apparent. Due to its high oil content, brown rice emits a rancid smell and changes in texture and appearance when its quality is no longer fit for consumption.
Rice is very easy to prepare and packed with essential nutrients, making it a suitable food for emergencies. It can last in your storage for several years and you can further extend its shelf life if you store it properly. Oxygen, high temperature, moisture, sunlight, and insects can degrade the quality of rice. However, once you eliminate these factors, you can keep your rice fresh for several decades.