Homemade Cola Syrup

Before you start

Cola flavor is a blend of citrus oils, warm spices, vanilla and a sharp acidity, all set against dark caramel. Commercial recipes are secret, but the profile is easy to recognize, and a home syrup can capture it well. Orange, lemon and lime zest give the bright top note; cinnamon, coriander, nutmeg and star anise give the spice; citric acid supplies the tang that makes cola taste crisp rather than just sweet.

Color comes from caramelizing part of the sugar until deep amber before the water goes in. That step adds a toasty bitterness that keeps the syrup from tasting like flavored simple syrup. This syrup contains no caffeine. Mixed with cold soda water, it makes a soft, aromatic cola that is less sweet than the store-bought kind.

Ingredients

• Syrup100 g (½ cup) granulated sugar — for caramel
• 500 ml (2 cups plus 2 tbsp) water — divided
• 300 g (1½ cups) granulated sugar — for the syrup
• Zest of 1 each orange, lemon and lime — removed in wide strips with a peeler
• 1 cinnamon stick
• 1 tsp coriander seed — lightly crushed
• 1 star anise pod
• ¼ tsp freshly grated nutmeg
• 5 g (1 tsp) citric acid — sold for canning or baking
• 1 tsp pure vanilla extract
• Per glass45 ml (1½ oz) cola syrup
• 180 ml (6 oz) cold soda water
• 1 lime wedge

Method

1. Measure 100 ml of the water and keep it by the stove. Put 100 g sugar in a dry, heavy saucepan over medium heat.
2. Let the sugar melt without stirring, swirling the pan as edges liquefy. Cook until it is a deep amber, the color of strong tea, about 6 to 8 minutes.
3. Take the pan off the heat. Stand back and pour in the 100 ml water; it will spit and seize. Return to low heat and stir until the hard caramel dissolves.
4. Add the remaining 400 ml water, the 300 g sugar, citrus zest, cinnamon, coriander, star anise and nutmeg. Bring to a gentle simmer and cook for 5 minutes.
5. Remove from the heat, cover, and steep for 30 minutes. Strain through a fine strainer into a heatproof jar.
6. While the syrup is still warm, stir in the citric acid until dissolved, then the vanilla. Cool completely and refrigerate.
7. For each drink, fill a glass with ice, add 45 ml syrup and 180 ml soda water, and stir once. Squeeze in the lime wedge.

Tips for success

• Peel the zest thin, with as little white pith as possible. Pith steeped for half an hour makes the syrup bitter.
• Stop the caramel at deep amber. Past that point it turns acrid quickly, and the burnt taste carries into every glass.
• Taste the finished syrup with soda before adding more citric acid. It should be lively but not sour; add ¼ tsp more if it tastes flat.

Substitutions

Citric acid

Use 30 ml fresh lime juice per batch instead. The cola will be softer and the syrup keeps only about 1 week because of the fresh juice.

Granulated sugar (syrup)

Swap up to half for light brown sugar for a rounder, more molasses-tinged cola.

Coriander seed

A pinch of ground cardamom or 2 crushed green cardamom pods adds a similar floral spice note.

Variations

Cherry cola

Add 15 ml of tart cherry juice or homemade grenadine to each glass along with the syrup.

Vanilla cola

Simmer half a split vanilla bean with the spices and double the vanilla extract.

Troubleshooting

The caramel turned to a hard lump

That is normal when water hits hot caramel. Keep stirring over low heat; it will dissolve within a few minutes.

The syrup tastes burnt

The caramel went past amber. Start again and pull it off the heat a little earlier; the color darkens even after removal.

The cola tastes flat and sugary

It needs more acid or citrus. Add a little more citric acid, or a squeeze of lime in the glass.

Storage

Refrigerate the syrup in a closed jar for up to 3 weeks. Discard it if it clouds, smells fermented or shows mold. Mix individual glasses to order.

Safety notes

Caramelized sugar is far hotter than boiling water and sticks to skin. Keep children away from the stove, add water off the heat with your arm back, and let the pan cool before cleaning.