Longtime readers will assume Burnt My Fingers has jumped the shark when I tell you we spent last weekend forming carrot juice and pea soup into little globules. I have been doing some work with the folks at Modernist Pantry, and for my first experiment proprietor Christopher Anderson advised me to try spherification which is the “gateway drug” for many new enthusiasts.
Spherification depends on the chemical reaction of sodium alginate and a calcium salt. Sometimes the alginate is in a bath, sometimes it’s in the food product. I started with reverse sperification (alginate in the bath, calcium in the food) because it’s supposedly easier. After an afternoon I had a small cup of orange globules, only a few of which exhibited the desired symmetry you’ll see in just about any “molecular gastronomy” food porn. (Most chefs hate that term, it turns out. It’s meaningless because everything is made of molecules and it’s overly technical-sounding. “Modernist Cuisine” is preferred because it describes the broad spectrum of new explorations in food preparation.)
There are some excellent videos on Modernist Pantry’s ChefSteps partner site that make it look easier than it is. (You get a URL to unlock the spherification course when you buy one of their kits.) My liquid initially wouldn’t spherify but just dispersed into the solution. I then added xantham gum and got something closer to globules but they were very irregular. What finally worked was to take a food service syringe filled with liquid and squeeze out a drop into a quarter teaspoon measure held just above the surface of the alginate bath, then flip the spoon to dunk the drop into the bath. In the end, maybe 10% of my efforts were good enough to keep. But I am sure with practice this will go up.
Next, I tried frozen reverse spherification for the peas. Strained pea soup was frozen in a silicone mold (each half-sphere is about a tablespoon) then the results were individually dipped into the alginate bath which had been heated to 125 degrees F. The principle here is that as the outer surface of the ice melts, it interacts with the alginate and forms a shell that will contain the rest of the contents. This worked fine until the bath cooled down, at which point I got a lot of gummy (from the alginate) pea soup.
I had a hard time finding solid reference information. Modernist Cuisine: The Art and Science of Cooking (the five volume version; the home edition doesn’t cover processes involving specialized equipment) is massive and intimidating and the many internet sites often aren’t clear on methods. This subject longs for a “science project” book in which you tackle a recipe and a technique, learn something of the chemistry, and end up with an edible result plus ideas for other things you can make in the same way.
A few trial-and-error discoveries are worth sharing:
Mixing an alginate bath is tricky. The powder starts to hydrate immediately when it contacts water, so you have to keep it dispersed by using a whisk or a blender. Then, you have to wait for the air bubbles to percolate to the top and pop. This can take 24 hours or more. If you like, you can buy mixes like Modernist Pantry’s Sphere Magic that simplify and speed up the process.
If your “flavorful liquid” is much thinner than the alginate you’re putting it into, and it disperses and doesn’t gel, you can thicken it with xanthan gum. Measure out 0.5% the weight of the liquid in xanthan gum and sprinkle this over the surface of the liquid in a wide dish; if you add the xanthan all at once it will clump up. Wait a few minutes for it to hydrate. If it has a vaguely slippery feeling when you touch it and rub your fingers together, that means the xanthan gum is being absorbed. If you still have problems with dispersal, measure out another 0.5% xanthan by weight and repeat.
When working with alginate baths, don’t pour the residue down the kitchen sink. It will interact with calcium in the pipes and can plug them up. Instead, wipe off as much as you can from spoons, surfaces and containers with paper towels and dispose of the paper towels in the garbage. Then pour the residual solution in the garden. It’s a natural product, made of algae, so should not produce any problems with your plants.
Finally, don’t plan on eating your first products. Get the technique down first. Of course I couldn’t resist, and my little amuse bouche tasted like… peas and carrots, from the frozen Birdseye pouch.