February 7th, 2011
So how does one use dry ice to preserve wheat or other grains, beans, or coffees in 5-gallon buckets and seal them correctly? Where do you find dry ice?
Enquiring Minds Want to Know
We’ve had several letters this week asking for more specifics on the process. Here is a more detailed explanation:
First it’s recommended that you line your plastic bucket with food-grade plastic or Mylar before filling your bucket with food. Wipe off any accumulated frost off the ice and wrap it in paper towels or something similar so it doesn’t burn anything it comes into contact with. (PLEASE NOTE: Dry ice will cause burns to the skin from merely touching it! It’s very, very cold! Use gloves when handling!)
Put your dry ice in the bottom of the container and fill with your food. About 4 ounces per 5-gallon bucket is plenty. Shake or vibrate it to get as much density in the packing as possible and to exclude as much air as you can. Put the lid on, but do not fully seal it. You want air to be able to escape. After you’ve put the lid on, you don’t want to move or shake the bucket while the ice is sublimating. (Dry ice is frozen carbon dioxide, and as it evaporates, the gasses rise, pushing out the oxygen from the container.) After about three hours you should be able to seal the lids, but check on the container every 15 minutes or so for about an hour to make sure pressure isn’t building up. While a little positive pressure is a good thing, don’t allow the lids to bulge. Once you’re satisfied the process is finished, put them away in an area with adequate ventilation. Because CO2 displaces oxygen and is odorless, if the gasses escape and there is no ventilation, you could easily become asphyxiated when entering the room.
Be aware that (because dry ice is very cold) if there is much moisture in the air that’s still inside the container, it will condense. If there’s enough condensation, it’s going to cause you trouble. You need low relative humidity when packing your buckets or processing them in an air-conditioned house would work as well. You can also use a desiccant package along with the dry ice to absorb any moisture. Dry ice may be found at ice houses, welding supply shops, some ice cream stores, meat packing companies, or in the yellow pages under the headings “dry ice” or “gasses”.
I’m just getting into long-term food storage and am wondering: Where do I purchase whole grains that can be milled into flour?
So glad to hear that you’re starting your long-term food storage plans! Some places to find whole grains are health and natural food stores, farmers co-ops, and online at places such as Pleasant Hill Grain or Bob’s Red Mill. If a local bakery purchases whole grain and mills their own flour, you might be able to purchase a supply from them as well.
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