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I am not sure about the right terminology as I am not a native speaker, but is it possible to conserve solid food in a jar with a candle?

Boiling is used to decrease air and for the food to be well conserved it must not have much oxygen. The food is suffocating. A tea candle placed inside will suck the air too and will extinguish when there is no sufficient air inside.

Corelation
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    The main purpose of boiling when canning isn't removal of air. It's done to kill microbes and their spores. – Deolater Feb 12 '19 at 14:31
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    @MatthewRead Boiling in a pot releases [water vapor, not steam](https://www.quora.com/What-is-the-difference-between-steam-and-vapour). Heating the air causes it to expand significantly, reducing the amount of air molecules in the jar. By sealing it before it cools, you can create a partial vacuum in the jar which helps to preserve food (but not from anaerobic microbes.) – JimmyJames Feb 12 '19 at 18:32
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    Paraffin wax used to be commonly used as a cover for jams and jellies. It kept the food anaerobic without having to go through the whole rigamarole. That said, I would not trust what is used for wax in modern candles. Some are quite the miracles of chemistry, and decidedly *not* food grade. You can still buy paraffin in most canning aisles. – Wayfaring Stranger Feb 13 '19 at 00:15

3 Answers3

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The short answer is: No.

The more elaborate answer is that certain bacteria are anaerobic and food needs to be heat treated to ensure it can be safely stored. Especial mention: Clostridium botulinum which leaves deadly toxins.

The tealight inside the jar will not produce the heat needed for pasteurization.

BaffledCook
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    That's aside from the fact the food will smell of burned candle-wax ;) – Tetsujin Feb 12 '19 at 10:28
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    @Tetsujin Well ... I dunno, maybe paraffin is an acquired taste? :-) – BaffledCook Feb 12 '19 at 10:36
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    For that authentic "70's restaurant with dribbly candlestick wine bottles on the table" vibe. – Tetsujin Feb 12 '19 at 10:38
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    Just a note, to kill botulin spores, you must get the food above normal boiling temperature using a pressure cooker. – JimmyJames Feb 12 '19 at 16:58
  • A candle placed below ceramic pod full of aroma oil is sufficient to vaporize it, and the candle is not even enclosed. I am not totally convinced that a sealed candle in a jar wouldn't create sufficient heat. Especially it depends on the size of the jar and the type of food. I think it is a matter of efficiency, but I could be wrong too. – Corelation Feb 13 '19 at 00:27
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    @JimmyJames This is technically true, but boiling water canning is only used to destroy harmful microbes in items which are acidic, salty, or sugary enough to prevent the growth of most other microbes, including botulin spores (though you should still be cautious of feeding these to very young children or the immuno-suppressed). Pressure canning is a more sure way to destroy more hardy microbes and can thus be used to preserve less acidic items. – Bloodgain Feb 13 '19 at 00:28
  • @BloodGain Thanks for adding that for completeness. I felt it was important to point out that boiling at or around 100C is not, by itself, enough. Anyone who is canning should follow proven guidelines in any case. – JimmyJames Feb 13 '19 at 14:42
  • @JimmyJames Agreed 100%. I've diverged from recipes, but I was specifically pressure canning or had good knowledge that what I was doing did not diverge from safe practices (i.e. canning jam), and I still checked multiple references to make sure I was within my risk tolerance. – Bloodgain Feb 13 '19 at 17:54
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    @Corelation The candle won't burn very long in a closed jar. You can easily test this, just put a lit candle in a jar and close it. A candle needs a continuous supply of oxygen to burn. It's going to take a while for a candle to heat up the contents. You can simulate this by taking a jar and filling it half full of water and then placing it over a candle. I doubt it will reach boiling temperature. Aromatic oils are often called 'essential' oils because they readily evaporate. A little heat simply speeds this process up. – JimmyJames Feb 13 '19 at 18:09
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I can't add a comment but would like to point out that I have seen melted paraffin used to create a sort of seal on the top of a jam/jelly preserve.

That doesn't prevent spoilage by mold or bacteria but it does keep a skin from developing or oxidation of the surface layer. Since paraffin shrinks a fair bit as it cools, this approach does have limits.

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It comes down to how hot you can get the can get the jar with a candle.

If your food contains water, then it will only heat above 100° C if it is under pressure, which means you'll need to seal the jar. Maybe, the jar is strong enough that its internal temperature could reach 120° C. If so, then maintaining that temperature for a while would kill all the microbes, and the food would be preserved.

On the other hand, maybe the pressure inside the jar would cause it to explode before the desired temperature was reached.

On the other other hand, maybe the jar would radiate heat too quickly--and absorb heat from the candle too slowly--so that it would never reach 120° C. You might be able to work around this by building some kind of reflective insulating enclosure for the jar, but it would be difficult to properly insulate it without also cutting off the air to the candle.

So the answer is maybe but I wouldn't recommend it.

MatrixManAtYrService
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