Stretchy ice-cream

This year is the "Year of Chemistry" and in August we also have "Wellington on a Plate" - so to celebrate both, the Chemistry Department of Victoria University invited Kent Kirshenbaum from New York University to present a couple of lectures this week on Chemical Gastronomy. Kent has founded a group in the States called Experimental Cuisine, which aims to understand the chemical and physical process of cooking, and is on a mad-cap adventure to find alternatives to traditional ingredients.  For example, pavlova without egg whites?! The idea is that chefs can learn a thing or two from chemists, and likewise chemists could learn a thing or two from chefs. Good stuff.

Kitchen chemistry is hot news right now - Kent said it was listed number 5 in Time's Top 10 list for 2010, wedged in between global warming and stopping terrorism! Certainly we've been enjoying our cooking shows on TV the past few years, learning how to make mango caviar using sodium alginate (the ions form a bridging link, pulling the polymers together), and learning that by precisely cooking an egg at 62.5 degrees C (in a water bath which looks suspiciously like the one in my old molecular biology lab) the cooked yolks are supple enough to be rolled out like pastry. Hmmn, that gives me a few ideas... If you want to read some more on this subject, and try some experiments yourself, check out  Cooking for Geeks by Jeff Potter and Molecular Gastronomy by Herve This.

But what interested me the most in Kent's talk was the prospect of making my very own stretchy ice-cream from none-other-than one of my all-time favourite plants, Amorphophallus konjac! Traditional stretchy ice-cream, or Salep Dondurma as it's known in Istanbul, is made from milk sweetened and flavoured with mastic, an aromatic resin, and thickened with salep, the powdered bulbs of wild orchids. Not just any orchid, but orchids from the Anatolian mountains - Orchis mascula or Orchis militaris - which look a little like a Hyacinth in flower. The orchid bulb contains a mucilaginous carbohydrate called glucomannan which, when dissolved in milk, binds up and blocks the movement of water molecules, thickening the milk. "Salep" is an Arabic word for "fox testicle", presumably referring to the shape of the orchids bulb (I am unable to confirm the likeness due to the general shortage of Vulpes vulpes in New Zealand). Salep is becoming expensive and hard to source, as the orchids are becoming increasingly scarce in the wild. But good news! there are other botanical sources of glucomannans which can do the job.  Enter again my dear Amorphophallus...

I've had this plant for over twenty years now. It comes up every spring time, forms this luscious green canopy with a leopard-spotted trunk, always attracts lots of attention and comments, and then dies back at the start of the winter to it's underground corm. When the plant has stored up enough energy, it flowers - an enormous black/purple arum flower on a stalk, which stinks like a dead hedgehog... Mine has only flowered twice in twenty years - and it goes outside when it does! Each year the big corm creates lots of new little corms, so eventually I had a small forest in my pot, and I have given tens of them away over the years. Kew Gardens have a giant species - Amorphophallus titanum - standing about 3m tall with a trunk about 15-20cm in diameter. I will try and find my photo of it and post it here.

 

Amorphophallus in flower - phew

Amorphophallus titanum, at Kew Gardens in London.

Anyway, back to the stretchy ice-cream.... Amorphophallus konjac also has a high glucomannan content, and can apparently be used as an alternative for salep. Konjac flour looks to be readily available in Japan, and is used for all sorts of things. But I'm wondering, in the spirit of having a botanical picnic, if I can just dry a corm or two out and process the flour myself at home?


Should you wish to try it too, here is the recipe for Konjac Dondurma
2 grams mastic (optional)
8 grams konjac flour
1.6 L whole milk
410 grams sugar

The corms

2 Litres of liquid nitrogen (for cooling. You could probably cool the ice cream in the usual, less dramatic, way. Maybe an ice cream maker would work too?).

I'll let you know how mine turns out.