Honeycomb candy making

What it is

Pour a spoonful of baking soda into bubbling hot caramel and it erupts, foaming up into a golden, airy mass riddled with bubbles that sets hard and shatters into the crisp, melt-in-the-mouth treat known as honeycomb, cinder toffee, or hokey pokey. Honeycomb candy making is the quick, dramatic process of cooking sugar and syrup to the right temperature, then aerating it with bicarbonate of soda so it puffs up into its signature bubbly structure. It is one of the most fun and theatrical sweets to make, and needs only a few cheap ingredients.

The appeal is the spectacle and the speed. The moment the soda hits the hot caramel and the mixture triples in volume in seconds is genuinely exciting, and the whole thing is done in minutes. Broken into shards, honeycomb is delicious on its own, dipped in chocolate (the classic Crunchie-style treat), or crumbled over ice cream and desserts. For very little money and effort, you get an impressive, crowd-pleasing sweet that always draws a reaction.

The science is a chemical reaction. Heating bicarbonate of soda makes it release carbon dioxide gas, and when you stir it into molten sugar that has reached the hard-crack stage, the gas inflates the syrup into thousands of bubbles, which set in place as the candy cools and hardens. Getting the sugar to the right temperature (the hard-crack stage, around 150°C) is what makes it set crisp rather than chewy, so a sugar thermometer takes the guesswork out.

The main hazards are the heat, molten sugar is extremely hot and sticky, and the tendency to overstir, which knocks the air back out. Quick, gentle folding and immediate pouring are key.

How it works

Have everything ready before you start, because once the sugar is hot it moves fast. Line a tin or tray with parchment (honeycomb expands a lot, so use a deep one), measure out your bicarbonate of soda, and have a whisk ready. Combine sugar and golden syrup (or glucose) in a deep, heavy pan, far deeper than the liquid needs, because the mixture will foam up dramatically. A deep pan is genuinely a safety point, not just convenience.

Cook the sugar to the hard-crack stage without stirring much. Heat the sugar and syrup, swirling rather than stirring, until it reaches around 150°C on a sugar thermometer and turns a deep amber. Temperature is what determines the final texture: too low and the honeycomb stays chewy and sticky, too high and it tastes burnt. A thermometer removes the guesswork, but the deep amber colour is a strong visual cue. Take it off the heat the moment it is ready.

Add the soda, fold quickly, and pour at once. Tip in the bicarbonate of soda and whisk just enough to combine it as the mixture erupts and foams up, then immediately pour it into your lined tin without stirring further. Do not knock it down or spread it, just let it settle. Overstirring collapses the bubbles. Leave it completely undisturbed to set hard, around an hour, then break it into shards. Store it airtight, since honeycomb absorbs moisture and goes sticky in humid air.

Benefits

A Genuinely Theatrical Sweet to Make Done in Just Minutes Costs Almost Nothing Delicious Plain or Chocolate-Dipped Always Gets a Reaction A Fun Bit of Edible Chemistry

What you need

Here's what to gather before you start. The essentials are marked.

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Caster or granulated sugar: the bulk of the candy

Golden syrup or glucose: to help it cook smoothly

Bicarbonate of soda: the raising agent that makes it foam

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Bicarbonate of soda

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A sugar thermometer: to hit the hard-crack stage reliably

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Sugar thermometer

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A deep, heavy pan: it foams up dramatically, so depth matters

A lined tin or tray: deep, for the expanding candy

A whisk: to fold in the soda quickly

FAQs

Why did my honeycomb turn out dense and flat?

Almost always overstirring after adding the bicarbonate of soda. Once the soda hits the hot sugar and foams up, every extra stir pops the bubbles and lets the gas escape, collapsing the airy structure. Whisk just enough to combine the soda, then pour immediately and leave it completely undisturbed to set. The other cause is sugar that did not reach a high enough temperature, which gives a chewy, sticky result rather than a crisp, airy one.

Do I need a sugar thermometer?

It is strongly recommended, though not absolutely essential. Honeycomb needs the sugar to reach the hard-crack stage, around 150°C, to set crisp rather than chewy, and a thermometer takes the guesswork out of hitting it. Without one, you rely on judging the deep amber colour, which works with experience but is easy to misjudge, undercook and it stays sticky, overcook and it tastes burnt. For a few euros, a sugar thermometer makes the result far more reliable.

Why does my honeycomb go sticky after a while?

Honeycomb is hygroscopic, meaning it readily absorbs moisture from the air, which turns the crisp shards sticky and soft. The fix is to store it in an airtight container as soon as it has set and broken, ideally with the air kept dry. In humid weather it goes sticky faster. Chocolate-dipping the shards also helps seal them against moisture. So airtight storage straight after setting is the key to keeping it crisp.

Is it dangerous to make?

The main hazard is the molten sugar, which is extremely hot, far hotter than boiling water, and sticky, so a splash causes serious burns. Use a deep, heavy pan since the mixture foams up dramatically, keep children and distractions away during the hot stage, and handle the pan carefully. The chemistry itself is harmless. Treat it with the same respect as any sugar work, an adult should handle the hot pan, and it is a safe, fun process.