Using Dry Ice For Proper Long-Term Food Preservation

Long-term Food Preservation Using Dry IceAs we prepare to face the unforeseen future, we preppers have to figure out how to solve a lot of problems. One of our main concerns remains how to preserve food and water for long periods of time. Today, we will discuss about how to store food using dry ice. It is a cheap and viable method that is not as popular as the one involving oxygen absorbers.

There are many projects available to help you preserve your food storage. Some are very popular, while others seem too complicated even to bother trying them. Using dry ice is an alternative method to preserve your food stockpile.

While it is a little bit more complicated than using oxygen absorbers, it is much cheaper.  Even more, depending on where you live, this method can be easier to do since you can find dry ice easier — actually, most large grocery stores, as well as welding supply companies, stock dry ice. When it comes to oxygen absorbers, you usually have to order them online.

What is dry ice?

Before we go further, I think it’s best to specify what dry ice is and how it works. To put it simply, dry ice is nothing more than frozen carbon dioxide gas. A solid block of CO2 which is broken into chunks and uses for various tasks. Dry ice warms at room temperature and turns into a harmless gas.

It’s important to mention that one pound of dry ice will turn into about 8 ½ cubic feet of gas. As you can imagine, it does not take much to fill the air spaces around your tiny grains of rice or wheat.

The main risk I’ve noticed when using it to preserve grains is that you can accidentally use too much of it. While it can successfully replace the oxygen in your food storage buckets, using too much will pop the top of your bucket.

The other risk with dry ice is that it becomes a solid at 110° F below zero. This means that frostbite is likely to occur if you handle it improperly. The CO2 will also displace the oxygen in the air, so I recommend handling it outside or in a well-ventilated room if you don’t want to suffocate.

And another tip which you may not be aware of is that some farmers are using dry ice to dispatch of small livestock such as rabbits and chicken. It is a humane way to put them to sleep if you will. I haven’t tried this personally, but after talking with various people, apparently, it works pretty well.

Recommended reading: Prepping Your Pantry For The Long Haul

Establishing how much dry ice you should use

We said above that one pound of solid carbon dioxide can produce about 8.5 cubic feet of gas. To keep it on the safe side, let’s say eight cubic feet will be the best (or closer) measurement if you will. A 6-gallon bucket is 1.46 cubic feet of space, this means that one single pound of dry ice will fill a lot of buckets.

If you add to that the food itself, which takes up space as well, you will only need about .5 cubic foot of gas per 6-gallon bucket. You will be able to fill around 80 buckets with 5 pounds of dry ice if you are using one once of solid CO2 per bucket.

And don’t worry if you have some dry ice left after filling all your buckets. You can do all sorts of neat tricks with it to entertain the kids.

If you plan to use dry ice to purge out and replace the air in your food buckets, you need to pay attention to quality. You should make sure the dry ice you are getting doesn’t have frozen water crystals on the block. If that’s the case, when the CO2 melts, the water will drip down at the bottom of your food buckets. The last thing you need is to discover 15 years from now when opening the buckets, that water has spoiled and grains, leaving you with a disgusting slime.

To figure out if the dry ice has water crystal you should check it carefully. It’s pretty simple to spot the water crystals since dry ice is light blue while frozen water is white. When you bring the block of  CO2 home, store it in a plastic container with a tight lid (no an airtight one). The dissipating CO2 will push water away and it will form frost on your container instead of on your block.

Using dry ice to preserve grains – Step by step guide

You will need the following materials:

  • A bucket with a tight-fitting lid
  • Some dry ice in a plastic container.
  • A small hammer to break the block of CO2
  • Small scale to measure the weight of dry ice chunks
  • Paper towels that you will use to keep the dry ice separate from your food
  • Gloves
  • Food to be stored

I have to advise you to avoid using glass containers or anything that can shatter under pressure. You will not be able to keep the dry ice cold enough at home and you risk of breaking the containers. Another important thing to mention is that you shouldn’t handle the dry ice with your bare hands as you will get frost bites.

Step by step procedure:

  1. Break your ice into small chunks. As a quick reference, one ounce by weight will be about 1/6, cup by volume.
  2. Add one ounce, or even two at the bottom of your bucket and mound it in a small pile in the center of the bucket.
  3. Cover the pile with a paper towel. This is not mandatory, but some people feel better knowing their food doesn’t touch the dry ice.
  4. Now it’s time to fill the bucket with food, but leave ½ inch of headspace.
  5. Place the lid lightly on top and wait for the ice to melt. If you seal the bucket immediately, the expanding gas will make the lid pop up or even explode your bucket.
  6. To figure out if the ice has evaporated you need to feel the bottom of the bucket. If it feels ice cold, the dry ice is still solid. From my experience, I can tell you that it takes almost a day for the solid CO2 to dissipate.
  7. Once the ice turned into gas, you can seal the lid completely.
  8. Wait half an hour before storing your buckets away. You need to check if the lids or sides of your buckets are bulged. If that’s the case, you still have solid CO2 in the buckets. Carefully crack the lid and check them again after 10 minutes or so.
  9. When you seal the bucket again, you may notice that a vacuum is present. The bucket sides may be sucked in a little. This is a normal thing, so you don’t have to worry about it.

When I store grains using dry ice, I fill 40 buckets with 5 pounds of solid CO2. I use 2 ounces per bucket to be on the safe side. If you want to stretch the dry ice, you can use one ounce per bucket. By doing so, you will double the number of buckets to be filled.


Using dry ice to preserve foods for long-term storage is a technique that works well if you pay attention to all the necessary steps. The only thing you need to understand is that this project requires proper timing and organization. If you buy the dry ice and you plan on doing it later, it won’t work. Even if you store the solid CO2 in your deep freezer, it will still dissipate. I recommend using it within 5 or 6 hours after you buy it if you don’t want to waste money.

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3 thoughts on “Using Dry Ice For Proper Long-Term Food Preservation”

    • No it does not freeze dry your food, it replaces the oxygen around your food with carbon dioxide which will preserve the dry grains, dry kibble for dogs long term. I recommend you purchase either a freeze drying machine or food dehydrator to process any fruits, vegs, or meats then you can place in a container with dry ice to replace the oxygen and seal the container, or take the foods after processing an seal in vacuum sealed bags for storage.. Always store in a cool dark place, basements are great along with root cellars..

  1. I’ve read that plastic buckets slowly allow O2 to pass through them. Will the CO2 eventually leak out too, allowing O2 in?


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