Reading about long-term bulk food storage, and on techniques to avoid infestation. Using dry ice seems to be the best, and cheapest method (as opposed to using oxygen absorbers).

Dry ice is a fumigant, it actively kills the insects that may already be in the grains.

Add a measured quantity of dry ice at the bottom of a bucket (~28.5 g per 25L bucket), cover dry ice with a paper towel, then place grains inside, filling the bucket up to within a 12mm of the top. Set the lid lightly on top and wait. Important not to seal the lid, as the carbon dioxide and air must have a place to escape.

How do you know when all the dry ice is gone and it's 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.

Obviously, it's important not to handle dry ice with bare hands, and to choose storage containers that are food-grade. Food-grade plastics are identified by the recycling number on the bottom. 1, 2, 4 and 5 are food-grade, but also to check to see if they are “food-safe”
Also, important to store them in cool areas, away from sunlight.

A final note, for long-term storage, choose low-moisture foods. Good candidates for long-term storage should have a moisture content of 10 percent or less (rice, beans etc). A moisture level over 12 percent encourages mould growth and chemical degradation of all grains.

@rek great thread! Are you willing to share your sources? That's something that I want to add to my knowledge graph, as long duration hikes are in my mind.

@rek wait. I guess I won't be hiking with ice in backpack.

On another note. Some company in my country is shipping ice cream in cardboard boxes with dry ice. And after shipment, you need to wait some time for ice cream to heat up, because they are stone cold.

@not7cd Sure. I want to further research what they say, as neither cite sources for anything. Their findings and recommendations are based on personal experience. I started researching dry ice for food storage after it was mentioned in the book 'sailing the farm' by Kenneth Neumeyer.

@not7cd Yea its pretty great, since it 'sublimates' rather than 'melts'. Leaves no residue behind.

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