A Sumatra Tonic is a cold coffee-based beverage that combines a shot of Sumatran espresso or cold brew with tonic water, usually served over ice and often garnished with a citrus slice or herbs like rosemary. The result is a sparkling, slightly bitter drink with a unique flavor profile: smoky, citrusy, and herbaceous, with a surprising smoothness that lingers on the palate.

Unlike traditional coffee drinks that rely on milk or sweeteners, this tonic-based twist lets the natural flavor of the coffee shine—enhanced, not masked, by the carbonation and botanicals in the tonic.
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