Sundays With Sparky: Reverse-Spherified Yogurt Blobs

This holiday season, Dr. Lasergonapus and his mother surprised Sparky and I with a beautiful molecular gastronomy kit.  It contained a number of cool cooking gadgets and several chemicals: agar-agar, sodium alginate and calcium lactate, xanthan gum and soya lecithin.

Sparky and I have actually used some of these ingredients before: agar-agar is a type of vegan gelatin based on seaweed commonly used in Japan. Sodium alginate is another seaweed extract, but it thickens when in the presence of calcium, similar to pectin, another heteropolysaccharide we use when making jam. Soya lecithin is an emulsifier that can form an attachment to both oil and water molecules, much like the lecithin in mustard that holds a vinaigrette together. Xanthan gum was the only really unfamiliar ingredient; it's a by-product of fermentation that is used as a thickener.

The fun with this kit is that these ingredients are processed so that they're significantly easier to use than their culinary counterparts - for instance, sodium alginate thickens without heat and can create little encased (or 'reverse spherified') globules of pretty much anything.  Using ordinary yogurt, we followed the package directions and made little burst-in-your-mouth yogurt blobs!

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