The Joys of Reverse Engineering

Two years ago I attended José Andrés’ Harvard lecture on hydrocolloids. He showed this video from his research kitchen as an example of the practical applications of various gelling agents:

That video has remained stuck in my head, due both to the clever ideas presented as well as the food porn quality. It came to mind again as I was struggling to come up with a dessert for new dinner guests, inspired by the mountains of boxed clementines that have invaded every supermarket. I can make that dessert, I thought. Most of the steps are explained, and some careful study should help me figure out the rest.

I began by blanching four clementines, guessing that two minutes would be sufficient. This step removed the wax from the rinds, which promptly precipitated on the walls of my pot. While the fruit cooled in an ice water bath, I made two cups of simple syrup. I added the syrup to a sous vide bag along with two clementines.

After two and a half hours in a 90°C water bath, I had two cooked clementines and a cup and a half of citrus-scented syrup.

After cutting an X on the underside, I ran a small spoon around the inside of the peel to loosen the fruit.

Taking care not to widen the cuts – easier said than done – I extracted the fruit with a tweezers, making sure I removed as much of the stringy pith as possible.

I ran the two blanched (but not cooked) clementines and the extracted pulp through my juicer. I hand-juiced a fifth clementine (I’m still not sure why this had to be done separately), dehydrated the juice for two hours at 65°C, then added a sheet of bloomed gelatin and microwaved to combine. Please excuse the absence of cool glassware and stainless countertops.

I mixed the two together, adding 0.1% by weight of xanthan gum, my best guess as to the identity of the unnamed hydrocolloid in the video. After a few hours in the fridge the clementine sauce wasn’t thick enough, so I added another sheet of gelatin and more xanthan.

I decided to go with chocolate rather than pumpkin seed as the complimentary flavor, so I made a chocolate sauce with equal volumes of the citrus simple syrup, chocolate, and butter.

I had to watch the video three times to realize that the “clementine sorbet” step wasn’t demonstrated at all. Either a miracle happened, or Andrés assumed if I got this far that a simple sorbet wouldn’t tax my skills. I juiced the rest of the box of clementines to extract three cups of juice, to which I added a half cup of sugar, a quarter cup of glucose syrup, two tablespoons of citron vodka, and 0.2% xanthan – the last three ingredients would reduce ice crystal formation and ensure a smooth-textured sorbet.

As soon as the sorbet came out of the ice cream freezer, I piped it into the hollow clementine shells, which I wraped in plastic to maintain their shape as they sat in the freezer.

I had planned on piping out the clementine sauce into a spiral and filling the space with the chocolate sauce, similar to the video, but I discovered that the chocolate sauce was more viscous then the clementine sauce, so I reversed the process, filling a chocolate spiral with clementine sauce. I cut the sorbet-filled clementines into sections, and lated a section along with a slice of aero chocolate. I added some chocolate-coverd cacao nibs as a garnish.

It’s hard to go wrong with pairing orange and chocolate, but what made this dessert interesting was the contrast between the paired preparations of each flavor: liquid clementine against icy sorbet, thick chocolate against airy mousse. I’d still like to figure out the proper textures for the sauces and add more color to the plate – perhaps a few raspberries.

Next up: figuring out Andrés’ cheese egg.


I served the dessert again yesterday, adding a few raspberries, and, at the sugestion of Maggie, some spiced whipped cream. In this case the cream was lightly sweetened with some of the clementine simple syrup and flavored with a dash of five spice powder. Both additions greatly improved the final plate.

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9 Responses to The Joys of Reverse Engineering

  1. iliana says:

    Wow, this is beautiful! And it’s making me lækker sulten, which translates as “hungry for delicious.”

  2. Diana says:

    I think I can solve the clementine juicing mystery. The blanched clementines are juiced skin and all, so you get a lot of oils from the skin and some bitterness from the pith. He uses a regular juicer, not a citrus juicer, so the whole shebang winds up in the juice. The hand- juiced clementine is pure flesh, no oils.

    We’ve also been playing with aerated chocolate!


    • David says:

      Thanks for the clarification.

      I’d like to learn about your results with the aerated chocolate. I’m having a lot of trouble preventing mine from crumbling when removed from the jars.

      • Diana says:

        We don’t do it in jars. We aerate in an overcharged isi canister and discharge on a parchment lined sheet, then slice the results.

  3. swain says:

    Try a shorter jar for the aerated chocolate. The taller jars that I noticed in the pictures are hard to get things out of in a good shape.

    • swain says:

      Oh…you can also try a spray or light neutral oil inside the jar before chocolate. Or parchment paper….although that would be a pain but would work. Last them make paper baking cups in all shapes that can be peeled away.

  4. Eric M. Van says:

    For those who are curious … this may have been the best dessert I’ve ever had in my life.* However, as chocolate, raspberry, and tangerine happen to be my three favorite flavors, it no doubt had an unfair advantage. Still …

    *To which Dave no doubt says, “hold it, you keep a list of your N [130, in fact] favorite movies of all time, in order, and a preference ranking of the X [81, actually] movies from 2011 you’ve seen so far, but you can’t say whether this was the best dessert you’ve ever had?” To which I must reply that, to the best of my memory, all things considered, yes, it was.

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