La ciencia que da al caramelo crujiente su característico aspecto de panal

It is made with granulated sugar and syrup, which are heated until melted. Then baking soda is added, the key ingredient for the bubbly appearance.

Sodium bicarbonate, with its basic pH, reacts with the hot sugar mixture, which is acidic, releasing carbon dioxide. The bubbles become trapped in the sugar mixture, just like in a cake that rises with the same leavening agent. To preserve them, the hot mixture is immediately poured onto a prepared baking tray and left to cool until it solidifies.

To make it at home, combine granulated sugar and syrup in a saucepan over low heat until the sugar dissolves, stirring constantly with a wooden spoon. Then increase the heat to medium-high and monitor the temperature with a candy thermometer until the caramel turns a golden amber color and reaches 146 degrees Celsius (295 degrees Fahrenheit), at which point it becomes brittle and crunchy.

Then remove from the heat and whisk in the baking soda, which has been previously sifted to avoid lumps, until fully incorporated. Avoid over-whisking, as this could disrupt the formation of bubbles, and use a large saucepan, since the mixture will foam when the baking soda is added. Pour the mixture onto parchment paper without spreading it with a spatula, let it rest for an hour and a half until it is cold and brittle, and then break it into pieces.

It allows for variations: a golden syrup made with sugar, water, and citric acid, very typical of British cuisine, can be substituted with equal parts honey and water, which gives a sweet, floral flavor with a touch of spice. Vanilla, dried ginger, or a pinch of nutmeg can be added along with the bicarbonate of soda.

Since caramel absorbs moisture, it's best to store it in an airtight container for up to a week. For extra crunch, the pieces can be dipped in melted chocolate, which creates a moisture barrier, or cut into rectangles to make Cadbury Crunchie-style bars.