Low Technology Institute

Link Worth Following: Ash Tomato Preservation

I try not to create a blog post on a single link, but in this case, it is worth it. As you know, we’re interested in ways to house, clothe, and feed ourselves with less reliance on fossil fuels. We’re always on the look out for new and old ways to preserve food without having to freeze them. Although freezing is convenient, it is only so because we have a superabundance of fossil fuels in our foodchain and homes.

In this story, reported by FarmRadio.fm, a tomato farmer in Berundi, Vital Nduwimana, was losing out on sales during the winter months, so he experimented with keeping tomatoes in various media to preserve them. He eventually found that burying tomatoes in ash preserved them for months.

The mechanism was unexplained, so I did a little digging. I was able to find a paper on using ash as a scrubbing agent for ethylene gas, but let’s start at the beginning. That smell of ripening tomatoes and bananas is ethylene gas, which is naturally occurring and harmless. It is a signal to nearby fruits to begin their ripening and helps plants synchronize their seed production. It is used in the grocery industry to ripen truckloads of green tomatoes before delivery to your grocery store. (Ever wonder why your “ripe” tomato tastes like a green one? It is because it is.) To remove this gas, it can be pumped through a scrubber. The study shows that ash, which contains carbon and potassium helps oxidize ethylene and renders it inert.

Mr. Nduwimana has stumbled upon what a few others have noticed (judging from a google search), but this method is worth some trialing next winter. Enjoy!

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