Butterfly Pea Syrup
Simple syrup infused with butterfly pea flower: inky blue in the bottle, and violet then pink once citrus arrives. The colour change is pH chemistry rather than stagecraft, and the flower contributes almost no flavour of its own.
Quick Facts
Flavour Profile
Primary Flavours
Tasting Notes
Barely there by design: a light, tea-like earthiness under plain sweetness. The colour is the point.
Storage & Handling
Refrigerated in a dark bottle: light dulls the pigment before time does.
Shelf Life
Home-made: about 2 weeks refrigerated.
Usage
Poured for colour first and flavour second, then acid added last and in front of the drinker. It turns the Witch’s Brew from blue to violet as the citrus goes in, and does the same in any drink with acid to spare.
A Flower With a Long Kitchen History
Butterfly pea is a Southeast Asian flower, Clitoria ternatea, long steeped into blue teas and rice dishes in Thailand and Malaysia before Western bars borrowed it.
Its pigments are anthocyanins, the same family that colours red cabbage and blackberries, and they are soluble enough that a hot syrup pulls the blue straight out of the dried petals. Nothing about the colour is added: it is simply extracted.
The Trick Is Honest Chemistry
Anthocyanins change structure with pH. Near neutral they sit blue, and as acid lowers the pH they shift through violet towards pink.
A blue drink handed over with a lemon wedge therefore rewrites its own colour in the glass, and there is no dye and no trickery involved. It is the same reaction that turns red cabbage water pink with vinegar, which is worth knowing because it means the effect cannot be faked with colouring and cannot be prevented either.
It Tastes of Almost Nothing
The flower contributes a faint earthy, tea-like note at most, and the sugar covers most of that. This is its virtue rather than a shortcoming.
Because it adds no flavour worth accounting for, the syrup drops into any citrus drink without bending the recipe. Build the drink as though it were plain simple syrup, and treat the colour as a separate decision from the flavour.
Making and Keeping It
Steep dried butterfly pea flowers in hot simple syrup for around ten minutes, strain, and bottle. It is a ten-minute job and the flowers are cheap.
The colour is what perishes rather than the syrup. Light dulls the pigment well before the sugar gives way, so keep it in a dark bottle in the fridge and make small batches. A faded syrup still sweetens perfectly and will no longer do the only thing it was made for.
Dried flowers keep far better than the syrup does, so buying petals rather than a finished bottle is the more practical purchase. A bag lasts a long time in a cupboard and a batch takes ten minutes whenever one is needed.
Top Tips
- Add the acid last and in front of the drinker: the shift from blue through violet to pink is the whole performance.
- The flower tastes of very little: mildly earthy, faintly like green tea. Build the drink’s flavour elsewhere.
- Colour fades with light and time: make small batches and keep the bottle dark.
Possible Substitutions
- Plain simple syrup plus a butterfly pea tea infusion
- Blue curaçao: the colour without the colour change, with alcohol and orange attached
Production Method
Simple syrup steeped with dried butterfly pea flowers (Clitoria ternatea), then strained. The flowers release water-soluble anthocyanin pigments that carry the colour into the syrup.
Common Questions
Why does butterfly pea change colour?
Anthocyanins. The flower’s pigments are pH-sensitive, sitting blue in a neutral drink and shifting through violet to pink as acid lowers the pH. Lemon or lime juice is all the trigger it needs, and the reaction cannot be faked or prevented.
Does butterfly pea syrup change the flavour?
Barely. The flower carries a mild, earthy, tea-like note that the sugar mostly covers. It is chosen for the colour, and the rest of the drink should be built as though it were plain simple syrup rather than a flavoured one.
Can I make butterfly pea syrup at home?
Yes, in about ten minutes. Steep dried butterfly pea flowers in hot simple syrup, strain and bottle. Keep it cold and dark, because the colour fades well before the syrup spoils and a faded batch has lost its only real purpose.
Should I buy the syrup or the flowers?
The flowers. Dried petals keep for a long time in a dark cupboard, where the finished syrup loses its colour within weeks, and a fresh batch takes about ten minutes. Buying a bottle means buying something already on its way to fading.
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Guide by Jerry Can Spirits