# Using Dry Ice To Preserve Your Food
> Even though the oxygen absorbers are easier, I prefer using dry ice to store my foods because it is so much cheaper. All one needs is the bucket with a lid that will make an airtight seal and a little dry ice. Dry ice is a solid and looks much like regular ice - except that it's -110 degrees F. below zero (-78.5C). You have to use a lot of caution when handling this product as it will burn your skin if it makes contact.
> 1/4 cup dry ice in hot water is great fun. Not to be used without adult supervision.
> Actually, dry ice can be a lot of fun. Put a cube in a glass of water and kids will watch the thick cloud that boils off . It will compete with your TV, at least for a while. When I was a kid back in the 50's we used to put dry ice in our home made root beer to make it fizzy. Dry ice is frozen carbon dioxide. Carbon dioxide is a harmless enough gas as long as it doesn't dissipate all the oxygen in the air you are breathing. I've heard some people say you have to do this outside as it displaces so much oxygen in the air that you will suffocate. I say, hogwash. Unless you are doing this in an airtight closet, there just isn't anything to worry about. Carbon dioxide is not a dangerous gas. In fact, we breath in air containing oxygen and breath out air containing carbon dioxide. There's carbon dioxide in our houses all the time simply because we are breathing. Carbon dioxide, in it's frozen form, is highly compressed compared to it's gaseous state. A pound of it contains enough carbon dioxide gas to make 8.3 cubic feet of carbon dioxide gas. A six gallon bucket contains 1.46 cubic feet of space. Fill the bucket full of beans or wheat and you have about 0.48 cubic feet of air left in the container surrounding your food. So, if you use twice as much dry ice as you actually need to displace the air in the bucket, you will need about .06 lbs, or right at one ounce of dry ice. Heck, be generous and put in two ounces of dry ice if you like. The smallest amount of dry ice I can purchase is 5 lbs which costs me $5.00. At even 2 ounces per bucket, that's enough dry ice to take care of preserving 40 buckets of food, more than I have ever done at one time. At two ounces per bucket, this is enough dry ice to push the air out of a six gallon bucket four times. You want a little bit of overkill or redundancy here as it's always better to overdo this than under-do it and have oxygen left in the container. Where To Get Dry Ice. I get all my dry ice from a welding supply shop. It is also often available at ice cream places and chemical supply houses. When you get your dry ice you need to bring your own container to put it in. There is one thing you really need to watch for if you are going to be using dry ice to preserve your foods. You must prevent water vapor from freezing on the outside of the dry ice. This moisture would later melt off the dry ice in the bottom of your bucket and increase the water content of your dried foods. As you don't often have a lot of room to play with as far as water content is concerned, it is important to ensure you don't add any moisture to your product with your dry ice. The dry ice you buy from the store should be water free, and that's the way you want to keep it. Dry ice is always giving off carbon dioxide gas, so it's relatively easy to keep the water moisture from it. Just be sure you don't put it into a container that breaths, like a paper bag or cardboard box. I use a Tupperware container which has it's own lid. This container is just right because it's lid is tight enough to keep water vapor from the ambient air out, but loose enough to permit the carbon dioxide gas to escape as it evaporates. By the time you get it home, there will be a thick layer of frost on the outside of the container - exactly where you want it, on the outside - not the inside. The inside will be moisture free because of the continually escaping carbon dioxide gas. There was one time I purchased dry ice which had a bunch of water crystals mixed in with it. You can tell this because there is a white powder mixed in with the dry ice cubes. Ice is just a tiny bit whiter than the light blue dry ice. You can put a teaspoon or two of this powder in a bowl, wrap plastic wrap around the top, and let it melt. If it's indeed water, when it melts you will get a little liquid in the bottom of your bowl. If it was dry ice, the bowl will be dry. I feel dry ice does not work well with powders, such as flour, powdered milk, eggs, cheese and things like this. I always put the dry ice on the bottom of the container before I add the product. The carbon dioxide, as it works it's way to the surface of a bucket filled with a powder would create pockets of gas inside the buckets, pushing the product out the top. You could put the dry ice on the top of the food when powders are being stored, but this would do nothing to get the oxygen out that is mixed in with the powder. But maybe I'm pulling hairs here. I'd suggest using the oxygen absorber method when storing powders. After you seal the container with oxygen absorbers in it, the absorbers have nothing but time to do it's thing. I use dry ice to preserve all my seeds. This includes all the grains and legumes. As long as it is a food which air can freely circulate around, dry ice will work just great. Dry ice will work fine with all the pastas as well. How long will dry ice last before it has all melted out of your Tupperware container? You should last 5 or 6 hours before it disappears on you. So, how do you do it? Materials Needed: A food scale, a measuring cup, dry ice, the food you are planning on preserving, and storage containers. The process: Zero your food scale with the measuring cup sitting on top of it. Open the container with your dry ice in it and take out about 1/3 cup and measure it. Depending on how your dry ice cubes are shaped, you should have about 2 ounces. (Remember, if you want to be stingy, one ounce will do the trick, that's 28.5 grams.)
> Two ounces of dry ice in the bottom of a plastic bucket.
> Pour this into the bottom of the bucket in a neat little pile and place a paper towel over the top. Why the paper towel? It keeps the dry ice away from the food, not that it's that important. Now place your product inside the bucket, filling the bucket up to within a 1/2 inch of the top. Set the lid lightly on top and wait. Recently, I have been sealing the lid all the way around except for one small side.
> Leave at least part of the lid unsealed until the dry ice has dissipated.
You DO NOT want to seal the lid completely as the carbon dioxide and air must have a place to escape. If the lid makes an airtight seal, the expanding carbon dioxide inside the bucket will continue to increase in pressure until something gives - either the lid will pop off or the bucket will split. Either way you are going to have food all over the place when this thing goes off. How do you know when all the dry ice has 'melted' and it is safe to seal the lid? Simply pick up the bucket and feel the bottom. If it is still icy cold there's still dry ice in the bottom. You may need to be a little patient here. My experience has been that it takes 1/2 to 1 hour for all the dry ice to change into a gas. You want to seal the lid just as soon as this has happened, however, because if you don't, air will start circulating back into the container. After 15 or 20 minutes, I start checking my buckets, and then recheck them every ten minutes or so. After you seal your buckets, it's always a good idea to keep an eye on the lids for the next hour or so. The lids will start bulging up if you sealed them a bit prematurely. If this happens, use a bucket lid remover to crack open the lid on one side to let the excess gas escape, then seal the lid back down. I'm not sure why, as my logical brain tells me it should be otherwise, but over the next several days there will usually be a small vacuum created inside the bucket and the side will pop in a little bit. Don't concern yourself with this. Your bucket will store just fine.
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