Hi.....I am working on a science project with my grandkids identifying crystals and have hit a real puzzler. We took some brine from a store-bought sour cabbage to see what might crystallize from the brine as it evaporated. In making the sour cabbage the producer said they added only 2% by weight Kosher salt and let the cabbage ferment for 2 weeks. The cabbage was not pasteurized.
We expected to see cubic NaCl crystals but, along with the normal salt crystals, was odd looking crystalline material as shown in the attached images taken with a binocular mic. The crystal morphology varies from snow-like to serrated laths to a cross-hatch fabric.
My guess is the material might be a product of fermentation. Any help would be greatly appreciated.
thank you
what you observe alongside the ordinary typical cubic crystals are so-called dendrites (evidently facetted forms), which can grow depending on undercooling/supersaturation and diffusion conditions. Hence the different shapes of the crystals you observe need not correspond to different types of salts, but only different morphologies which have developed. I think that everything may be NaCl.
To this, I would also add, some organic additives, be in less amount, can change crystal morphology significantly. And if the fermentation product is protein rich, there is some possibility of some salts of amino acids as well.
And thumbs up for your household experimentation!
Yes, they are dendrites. This form of crystals is said to form when the rate of diffusion is the limiting factor for crystallization. This would indicate the content of something that thickens the environment. It will probably be organic substances, may be lactates. Experiments with the crystallization of solutions (for example, soda) thickened with, for example, agar are interesting in this regard. Great for a start, keep it up.
Congratulations on your idea, creativity, and practice exercises with the younger generation!! I believe in previously advises. Consider doing X-ray diffraction measurement to confirm it.
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