There’s something about science experiments in the kitchen that kids find irresistible. Maybe it’s because you get to transform familiar ingredients into new concoctions, or maybe it’s because you (almost) always get to eat your creations. When I found out how easy it was to capture various liquids in little edible spheres, I couldn’t wait to get some mad science on in my own kitchen. These days, spherification is commonly used in many restaurants; it’s one of the easiest tricks in the molecular gastronomy toolbox.
I’ve enjoyed seeing delicious little pearls of such delights as beet juice, green tea, sugar cane juice on plates. For this edible experiment, you can work with water or coloured water. It’s also very fun to use non-pulpy juice to make even more delicious edible liquid balloons. You can find the necessary food-grade chemicals, both of which are naturally derived, online or at molecular gastronomy supply shops.
1/4 tsp sodium alginate (seaweed based)
1 tsp calcium lactate
1/2 cup drinking water or pulp-free juice
Small, medium and large bowls (2 cup, 4 cup and 6 cup approximately)
Immersion blender (or regular blender)
1 tsp measure with a deep bowl
Put 1/2 cup of water or pulp-free juice in the smallest bowl and add 1/4 teaspoon of sodium alginate to the liquid. Use an immersion blender to completely dissolve the sodium alginate. Set the mixture aside to allow air bubbles to dissipate.
Add 2 cups of cold water to the medium bowl. Whisk in 1 teaspoon of calcium lactate. It may not completely dissolve but whisk for a few minutes to get the majority of it to dissolve.
Add 4 cups of cold water to the largest bowl and set the sieve over top so that most of the sieve is under water. The sieve is not essential but it can make it easier to scoop out the water or juice balloons after they’ve been rinsed.
Line up your three bowls side by side.
Using the deep-bowled measuring spoon, scoop a full spoonful of the first mixture (liquid plus sodium alginate) which should feel slightly gelled.
Very carefully drop the gelled mixture into the second bowl (the cold water and calcium lactate mixture). It will take a little practice to get perfectly round spheres but the odd shapes taste the same and can be rather fun looking! You can also use a tiny spoon to make little pearls if you prefer.
Repeat the above two steps until you have three or four balloons in the middle bowl – avoid overcrowding the bowl. Using a finger or a small spoon, gently stir the liquid around the balloons for three minutes, keeping the balloons gently in motion.
Using the slotted spoon, carefully transfer the balloons to the third bowl to stop the chemical reaction and rinse them off.
Once they've been rinsed, use the slotted spoon to gently place the balloons on a plate and repeat with the remaining sodium alginate + water (or juice) mixture.
Your balloons will now be ready to carefully pick up, jiggle and, of course, pop into your mouth! They’ll feel a little slimy but will taste just fine. Make sure your laboratory assistants appreciate that they are EATING, not drinking this water (or juice).