Pour the tonic and the gin changes colour. It goes into the glass deep blue and turns pink as the mixer hits it, and the mechanism is chemistry rather than theatre: Clitoria ternatea, the butterfly pea flower, shifts hue with acidity, and tonic water is acidic. António Cuco distils it in the Alentejo at 40%.

Underneath the display there is a proper recipe. Strawberry and raspberry lead the aroma with a bright berry character, and the flower itself contributes colour far more than flavour, which is what allows the fruit to be tasted rather than merely looked at. Then the warm half arrives and it is the more interesting one. Ginger arrives with a prickling heat, cinnamon lays a drier and rounder warmth beside it, and cardamom lifts both with cool camphor. Lemon peel sharpens the top and stops the berries from settling into sweetness. Coriander seed ties fruit to spice, angelica root puts dry earth below, while juniper draws a clean line down the centre. The result is smooth and lingering, spice and fruit in equal measure.

Tonic is not optional here in the way it usually is, since the colour change is half the point and only an acidic mixer will produce it. Use a neutral one, ice the glass heavily, and pour the tonic slowly so the shift is visible. A strawberry repeats the recipe, and lemon peel is the sharper option, cutting the fruit. Sugar in the mixer is what ruins it. A gin that performs a trick still has to be worth drinking once the trick is over, and that is where most novelty bottles fail. The flower is a pigment before it is a botanical, and the recipe underneath does not depend on it. Colour is the easiest thing to sell and the hardest to justify twice. It ends fruity, spiced and smooth.