Cola Flavor

Cola takes its name from the kola nut, the seed of West African trees in the genus Cola. The nuts carry caffeine and theobromine and taste bitter at first. They have been chewed and traded in West Africa for centuries. American pharmacists put kola into fountain syrups in the late 1800s, and Coca-Cola's name comes from coca leaf and kola.

Today the nut does little of the work. Big brands add caffeine directly, and whether any kola extract remains in them is not published. What people recognize as cola is a blend of citrus, vanilla and spice, made sharp with acid and dark with caramel.

What cola is made of

The balance is where brands differ. Coke leans toward vanilla and spice. Pepsi reads sweeter and more citrusy, and lists citric acid alongside phosphoric. Dr Pepper is not a cola at all. It swaps the citrus lead for cherry and almond.

Nobody publishes a cola formula. So "cola" in a brief means very little until you name a reference product.

The acid is part of the flavor

Phosphoric acid gives a sharper, drier sourness than citric acid, with no fruit attached to it. A cola made with citric acid alone tastes closer to a lemon soda. See acidulants for how the common food acids differ.

Colas are also very acidic. One US study measured Coca-Cola Classic at pH 2.37 and Pepsi at 2.39. Most of the root beers in the same study sat between about 3.9 and 4.4.¹

If you want a "clean label" cola without phosphoric acid, expect the taste to change, not just the ingredient list.

Caramel color has a job to do

Colas use Class IV caramel, also called sulfite ammonia caramel. It holds up in acid and carries a negative charge, like the other components of a soft drink. A caramel with the opposite charge can attract them and leave a haze or sediment.

It matters on the spec sheet too. In 2012 Coca-Cola and PepsiCo had their suppliers change how their caramel was made. The aim was to cut a byproduct called 4-MEI under California's Proposition 65 rules. Both said their recipes did not change.² If you buy caramel color, ask for the 4-MEI specification.

Building a cola that holds up

Treat the citrus as the fragile part. Citrus oils do not dissolve in water. They go in as an emulsion, or as a washed extract with the terpenes taken out. They also oxidize first. When an aged cola tastes flat, it is usually the citrus that has gone, not the spice.

Keep some bitterness. Caffeine-free colas can taste flat and sweet. A flavorist will often add a little bitterness back to replace it.

Plan sugar reduction from the start. Sugar rounds off the acid and the spice. Take it out and the bite gets harsher. Coca-Cola Zero measured pH 2.96 in the same study, noticeably less acidic than the full-sugar drink. See sugar reduction.

Do not expect kola to carry it. Kola nut extract can support a label story. It adds little flavor, so it cannot stand in for the citrus, spice and vanilla.

Say cola, not a brand. "Cola" is a generic word. The brand names are not.