Alchemy At Home: Spheres & Siphons

Before Xmas I wrote a piece about Texturas - compounds that allow 'culinary alchemists' to produce such dishes as spherical ravioli, melon caviar and hot cranberry foam. My fellow chef Michael from work and I had bought some of these products with a view to experimenting at home. Well... Michael and I got together the other weekend with our Texturas, food ingredients and kitchen tools and we set to work.

And here are the results of our first proper domestic Texturas experiment... First on the agenda was a bit of basic spherification, a technique that Michael has had some practise with at work, making wasabi spheres for Comerç 24's entrecot dish.

As I was in possession of rather a large bag of good quality dehydrated rose petals (courtesy of Solé Graells), it made perfect sense to make our own rose water for the spherification. Now don't be put off by this seemingly bold suggestion, because it's actually a very simple procedure that you can easily achieve yourself. Bring a pan of water to the boil, add the dehydrated rose petals and wait until the water comes back to the boil, remove from the heat, cover and set aside for ten minutes to infuse. Simple enough. After ten or so minutes are up, pass the infusion through a fine sieve and taste for sweetness.

You'll probably find, as we did, that the rose water will require a little sugar to accentuate the delicate floral aroma. Once we were happy with our rose water, we let it cool and went about preparing the chemicals which would turn this simple liquid into little perfumed balls of delight. The first step was to measure the Algin, add it to the cold rose water and then use a stick blender to agitate the two together. This stage needs to be done as soon as possible (preferably even ahead of time), because the mixture then needs to be left to settle for a good while so the air that was incorporated into the liquid by the blending can naturally disperse. This process is very important because if there are any air bubbles in the mixture when you come to make the spheres you'll be left with holes in your spheres, which presumably you don't want.

While we waited for the rose/Algin mixture to settle we had time to measure out the Calcic for the calcium chloride bath. This is a much easier preparation and simply involves blending 2.5g of Calcic into 500ml of water. As we were working on a very small scale we didn't need half a litre for the water bath, so we scaled down the measures accordingly. Next to the water bath you also need to prepare another bath of clean, cold pure water which is used to wash the spheres of any excess Calcic once they've formed and are ready to be removed.

Now the boring part was over with, the fun could begin. "Eines" is the Catalan word for "tools", and the eines canister which comes with the spherification set contains all of the equipment necessary for making all the various spherical sizes.

Being sensible for once we decided to start small, and work our way up to full size spheres once we'd mastered the somewhat easier technique of caviar-making. For this you need the syringe provided with the Eines, so we loaded ours with the rose/Algin mixture. Holding the syringe over the Calcic bath, quite close to the surface, you very gently squeeze down on the plunger so that tiny droplets of the mixture fall into the bath. The liquid quickly gelifies on the outside as the sodium alginate in the mixture reacts with the calcium chloride in the water, forming spheres with thin membranes just like an egg yolk.

In fact if you were that way inclined you could actually create a false egg by cracking open the yolk, using the same technique with the liquid yolk as we did with the rose water, making a yolk sphere and then repeating the process with the egg whites but this time put the yolk sphere into the egg white/Algin mix in a much larger spoon and spherify the egg whites with the yolk sphere inside. It is actually possible, but would you really go to all that bother? I think not.

OK - back to the point. You need to leave the "caviar" in the Calcic bath for a few minutes until their membranes are sturdy enough to touch. Now you use the special slotted spoon provided to transfer the caviar into the clean water bath. They're now ready to eat. We then used the exact same process to make larger spheres, this time using a larger member of the set of spherical spoons. We served our rose caviar - both small and large spheres - for dessert, accompanied by fresh strawberries and some really good quality vanilla ice cream.

It's hard to get the full effect from still pictures, so we shot a couple of short video clips to demonstrate the spherification process. Have a look for yourself. The first video shows Michael using the syringe to drop the rose water in tiny pearls for the caviar. The second shows me rupturing one of our rose spheres to show that the inside is still completely liquid. The textural sensation of a sphere bursting inside your mouth is an experience in itself, but then as the stream of flavour-packed aromatic liquid flows out and fills the mouth it truly leaves you in a state of amazement.

As well as having experience with the spherification technique Michael is also somewhat of a dab hand with a cauliflower espuma as he prepares one at work for our rabo de torro dish. So we decided on a green cauliflower espuma with butifarra negra as our main course to precede the rose caviar dessert.

Butifarra negra is a quintessentially Catalan blood sausage, somwhat similar to our own black pudding. Its melting fatty texture and rich meaty flavour makes the perfect partner for a smooth and creamy cauliflower dish. This time we were using a green cauliflower or 'broccoflower' that I had provided. The colour might have changed but the principle remains the same as for an ordinary cauliflower: we removed the green leaves that surround the brassica, cut out the tough central stem and broke it down by hand into even sized florets.

These went into salted boiling water and were cooked until a knife ran smoothly in and out of the stalk of each floret. Strained in a colander, then into a bowl and puréed with full cream, a good seasoning of salt and a little freshly grated nutmeg.

The nutmeg has a wonderful effect with cauliflower, but the real trick at this point is to go against your instincts by deliberately over-salting the purée for your natural taste. I know this sounds strange and totally contrary to normal kitchen practice, but as I was informed by Michael (who was told by sous chef Oliver, who's done this many times at work) when you charge the cauliflower with compressed air in the siphon it loses strength of flavour. But when you release some of the espuma from the siphon and taste it you'll find that what tasted too salty before will now be just right.

OK, so once you've got your cauliflower purée, you pass it through a fine sieve and into the siphon it goes. While the cauliflower was boiling away we fried the botifarra negra whole and whacked them in the oven until they were bursting with fatty goodness.

I apologise for the lack of photos after this point, because I'd been rather snap happy during the cooking stages which resulted in a dead camera battery just as it was time to plate up. If by any chance you were wondering, I can tell you that it was lip-smackingly de-li-ci-ous. Served with some crispy deep fried julienne of leek, which added a crunchy texture to this luxurious dish. The flavour and texture of the rose caviar worked really well with the fresh strawberries which, being so far out of season, needed quite a big boost in both departments. All in all a grand success. We got down to some good culinary experimenting but more importantly our successes meant that we both ended the evening satisfyingly full from the results of our culinary efforts.

A bit long I'm afraid, but I had a lot to talk about and I hope you enjoyed it. I've got more bits and bobs in the pipeline for future Alchemy At Home posts, so there'll be plenty more where that came from...