Storing tomatoes in ash for months

Ken Hargesheimer sent us a copy of the "From Garden to Kitchen" newsletter published by UNICEF. It provides a way for Pacific Island populations to share gardening and nutrition information suited to the local region. If you are in the Pacific Islands, you are eligible to receive this newsletter (no fee). Write South Pacific Commission Community Education Training Centre, c/o UNDP, Private Mail Bag, Suva, FIJI; phone 300439; fax (679) 301667. The following is from issue #10.

Farmers know all too well the problem of large quantities of tomatoes (and low prices) during season, followed by short supply and higher prices. The Bureau of Education in the Philippines says you can extend the season in which tomatoes are available. Fresh tomatoes can be preserved in wood ash for up to three months.

Preserve only newly picked tomatoes which are ripe but not soft and overripe. They must be free of bruises and blemishes. Select a wooden or cardboard box or woven basket and line it with paper. Gather cool ash from the cooking fire and sift to remove sharp particles. Spread the ash evenly on the bottom, 1.5 inches (4 cm) thick. Arrange the tomatoes upside down (stem end facing down) in one layer and pour another thin layer of ash on top. Continue layering tomatoes and ash until the container is full. Cover and seal the container and keep in a cool dry place. [The article does not say how to cover and seal. My best guess is to cover with ash then a loose-fitting cover to keep the ash from being disturbed.] The skin will wrinkle but the pulp inside will remain juicy.

If I were serious about storing tomatoes for winter use, either in ashes, or on the counter-top, I could make the process much more effective by doing a couple of year's worth of selection for long-keeping traits.

Then one day, he noticed that the tomatoes he had kept next to his banana trees were not rotten. Then he noticed the ash at the foot of the banana trees.

He decided to try keeping his tomatoes in ash and found that this was more effective than any of the other techniques he had tried.

He uses ash from a chimney, and sifts it three or four times to remove large residues, debris, and other foreign materials. Then, he dumps the ash into a paper carton and places the tomatoes in the carton. With this technique, Mr. Nduwimana manages to safely store his tomatoes for many months.

He explains: “I keep my tomatoes in the ash for a period of five to six months, so I can sell them in December, January, or February when the price has risen—since tomatoes are rare and become expensive during this period.“

Joseph Lofthouse wrote:
If I were serious about storing tomatoes for winter use, either in ashes, or on the counter-top, I could make the process much more effective by doing a couple of year's worth of selection for long-keeping traits.

Jason Padvorac wrote:

Depending on how the ash preserves the tomatoes, there may be other applications. I wonder if it somehow hardens the skin, or manages the humidity levels, or kills decay agents, or what...

I suspect that potash (aka pot ashes) in the hardwood ash has a lot to do with it since "Potash is important for agriculture because it improves water retention, yield, nutrient value, taste, color, texture and disease resistance of food crops. It has wide application to fruit and vegetables, rice, wheat and other grains, sugar, corn, soybeans, palm oil and cotton, all of which benefit from the nutrient’s quality enhancing properties." [from Wikipedia, underlining mine] I am not looking forward to sifting my ashes but will give it a try!

pete king wrote:Potash and wood stove ash are 2 complete different things. Potash is a Potasium based mineral mined for use as an agricultral fertlizer.
Wood stove ash has a completely different chemical make-up.
Excellent discussion - tomatoes in winter NOT from Mexico!! wow!

pete king wrote:Potash and wood stove ash are 2 complete different things. Potash is a Potasium based mineral mined for use as an agricultral fertlizer.
Wood stove ash has a completely different chemical make-up.

The term potash comes from the Middle Dutch word potaschen (pot ashes, 1477).  

Michael Sohocki wrote:I am a chef, and we produce huge amounts of ash from wood fires of several kinds. I have used wood ask for an unthinkable number of things!

The one that applies most readily to this subject is tossing okra in wood ashes to keep them from going bad--the results are amazing. What used to go bad (you want them at all, you get a case minimum order in many circumstances) in about three days, with a liberal coating of ash we could hold for a month or more.

PH of wood ash is extremely high, so it makes life impossible for moat bacteria. I have also coated boiled eggs in it, which then dry to a course, shaveable consistency.

I also learned quite by accident mixing Ash with vinegar creates the same carbon dioxide gas release that is the chief reason for using baking soda. Having studied it more deeply, I found that the Pueblo Indians used culinary ash, or the white ash found on top of the pile that is most pure, with an otherwise acidic batter to create lift long before baking soda or baking powder ever existed.

Michael Sohocki wrote:Hi Peter.

I think "cream of tartar" is acidic. At least, there is a food additive called tartaric acid--although it is irresponsible of me to suggest without looking into it.

The Pueblo Indians relied on fermentation to lower the PH in wet grain mash. I don't remember which tribe, but human saliva (from a select human) was even used to promote a particular bacterial profile.

Adding acid to eggwhite (or any other protein that I'm aware of) denatures and lengthens protein chains. In original form, they are all crumpled up like tightly crunched tinfoil. Acid does something to their mollecular binding properties, causing them to dissociate, more like a box of loose rubber bands. A little of this is helpful in whipping eggwhites because longer protein chains can hold a greater volume of air. Like me.

Now back to basics....

Wood ash is highly basic--like your baking soda. In the Foxfire Books (a fabulous record of a pre-electric society getting along in the mountains), there is described a wooden trough, the bottom lined with straw and then
stones, followed by wood ash from the fire. They would pour water in the top incrementally, which would percolate to the bottom to extract a mild (solution) lye. By either drying or heating they would concentrate this down until an egg would float in it, and this was the basis for soap and many other cleaning products.

It might interest you that this same lye is how the Jews of Eastern Europe got that shiny, crispy glaze on the outside of pretzels.

So what does ash do to an egg? I know less about this than I do about acids--but alkaline definitely does weird stuff to protein. It certainly darkens and denatures, so the texture of muscle tissue becomes sort of plastid and bouncy subjected to alkaline solutions. It also becomes slimy. Have you ever gotten bleach on your fingers, and you feel that slippery thing going on? There is a reaction happening between the strong base and the protein that your fingers are made of (and if you leave it there, it can mess you up pretty bad). You can reverse this process with a few drops of vinegar.

Rolling a boiled egg in pure wood ash probably has less to do with chemical reactions (neither the egg nor the ash are in an aqueous solution that would permit the chemical to travel far) than the simple removal of water. (3 days is shaveable, but it will hang out indefinitely)

Pathogens "require a water activity level of 1.0"  to reproduce effectively, so a peeled boiled egg rolled in ash is pretty near impenetrable. Left on a wire rack they will dry to the size of walnuts, and almost as hard. The whites are very high in water and shrink considerably, while the yolk stays exactly its original size. The texture of the yolk is firm, like parmegiano reggiano or bottarga (both of which are intense, flavorful ingredients shaved and served in small quantities).

I microplane it over salads suggestive of caesar. The flavor of ash-cured proteins is more complex, and somehow reminiscent of oyster.