Edible Science: tiny juice balloons

A tasty molecular gastronomy kitchen experiment!

This is a fun project that kids really enjoy. The littlest ones can watch and then play with and eat the results, while older children and teens can probably do it all by themselves. While kids may not be familiar with molecular gastronomy, if you tell they they’re going to take a liquid (juice or water) and turn it into little balloons they can hold in their hand and then eat, you’re sure to capture their attention. The science behind this is called spherification and it is commonly used in many restaurants today because it’s one of the easiest tricks in the molecular gastronomy toolbox. I’ve enjoyed finding on my plate little pearls of beet juice, green tea, balsamic vinegar and more over the past few years. If you’re using water instead of juice, it might be fun to add a drop or two of food colouring so the experiment is more visually appealing. You can find the necessary food-grade chemicals, both of which are naturally derived, online or at molecular gastronomy supply shops. In Ottawa, contact Chef’s Paradise and in Toronto, Nella Cucina stocks the two products you’ll need and either would likely arrange for local contactless pickup or ship by mail order; Powder for Texture also ships nationally. Last comment: if you’re looking for other fun edible science experiments, check out this rock candy recipe and the instructions for making potato chips in the microwave. 

Ingredients

• 1/4 teaspoon (1.25 mL) sodium alginate (seaweed based)
• 1 teaspoon (5 mL) calcium lactate
• 1/2 cup (125 mL) pulp-free juice (or coloured water)

Equipment needed

• Small, medium and large bowls (2, 4 and 6 cup / 500 mL, 1 L and 1.5 L approximately)
• Immersion blender
• Whisk
• Sieve (optional)
• 1 teaspoon (5 mL) measuring spoon with a deep bowl (not a broad, flattish one)
• Slotted spoon
• Plate

Method

• Put the 1/2 cup (125 mL) of juice or coloured water in the smallest bowl and add 1/4 teaspoon (1.25 mL)of sodium alginate to the liquid. Use an immersion blender or very vigorous whisking to completely dissolve the sodium alginate. Set the mixture aside to allow air bubbles to dissipate.
• Add 2 cups (500 mL) of cold water to the medium bowl. With a clean whisk, whisk in 1 teaspoon (5 mL) 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 (1 L) 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.

• Using the deep-bowled measuring teaspoon, scoop out a full spoonful of the first mixture (liquid plus sodium alginate) which should by now feel slightly gelled.
• Very carefully drop the spoonful of 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 it doesn’t really matter – irregular shapes taste just 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 clean finger or a small spoon, very 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.

• Gently place the balloons on a plate and repeat with the remaining gelled sodium alginate + juice (or water) 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 and are perfectly safe to eat.