I ended my just-prior post with some speculation on the energy (in)efficiency of home canning. In this post, I work up the numbers and confirm that home-canned pickles require quite a bit of energy. My calculation is that I use 17 fossil fuel calories for every edible pickle calorie preserved.
As a way of contrast, I calculate that commercially-canned diced tomatoes require just 2 fossil fuel calories for every edible calorie preserved. (That’s only for the canning, not for the transportation, but despite what you may read, the energy used in transporting canned goods to the store is minimal. I may need to do a separate post on that.)
Much of that difference is due to the energy density of the foods (canned tomatoes have about 5 times as many calories per volume as canned pickles). Factoring that out, it appears that my home canning is maybe half as energy-efficient as commercial canning.
You may read blog postings and such suggesting that home-canning is a net energy saver, because you save the transportation costs for the food, and so on. I’m not sure sure about that. It’s entirely possible that the relative inefficiency of home canning offsets the fossil fuels used in transportation. But that’s part of a different calculation.
This is the energy used in canning (preserving) pickles. You can make pickles with no direct energy use, as in lacto-fermentation. But if you want to put your pickles on a shelf, to eat some time next year, you have to can them. That’s what we’re talking about.