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IF YOU eat at fancy places, you may have encountered orbs of sauce or puree, held inside a membrane, that burst in your mouth. Making them involves a little chemistry, but it can be done at home.

Now a staple of modernist cuisine, the spherification technique was patented in 1942 by food scientist William Peschardt and later popularised by chef Ferran Adrià at El Bulli restaurant in north-east Spain in the 2000s.

To try it, you need two special ingredients that can be ordered online. One is a salt called sodium alginate, which comes from brown algae. Alginate is formed of polymers made of chains of sugar molecules with negative charges. These polymers can link together to form a gel, but to do that, they need help from ions with a double positive charge. Sodium ions have a single positive charge, so they stick to the negative parts of the alginate, but can’t pull two polymers together.

The second ingredient is calcium lactate, another salt, this time containing calcium ions. Their double positive charge means they can attract two alginate polymers at the same time, forming the cross links we need to turn the liquid into a gel.

, then immersing drops or spoonfuls into a solution of calcium lactate. A gel skin should quickly form on the outside, trapping the liquid in the sphere.

My attempt to do this with mango juice hit a problem: when I mixed in the sodium alginate, it instantly formed a gel. Mangoes contain little calcium, but perhaps another mineral was causing the problem. This method can also fail if the liquid is too acidic.

Luckily, there is an alternative technique: reverse spherification. Here, calcium lactate is mixed with the flavoured liquid, which is dropped into a solution of sodium alginate. This results in a thicker membrane, but it should work with almost any edible liquid.

If you live somewhere with hard water, like London, your tap water could turn to jelly on contact with the alginate, so use bottled water for the alginate bath if you have to.

Sodium alginate dissolves poorly, so create your solution with a blender or hand mixer, then let it sit so any air bubbles escape.

To make mango spheres, dissolve the calcium lactate in the mango juice. Fill a hemisphere-shaped tablespoon measure and tip it into the alginate bath. Use a spoon to rotate the sphere as the gel sets. After 1 minute, take it out of the alginate bath with a strainer and put it into a water bath.

You can also use a pipette, syringe or squeezy bottle to make small drops that form , but this is trickier because the spheres tend to stick together.

The membrane is permeable, so if you want to make the spheres in advance, store them in mango juice so the flavour doesn’t escape.

For other projects visit newscientist.com/maker