Nannari — "Indian sarsaparilla," the aromatic root of the slender climbing vine Hemidesmus indicus — is a cooling flavouring at the heart of South Indian summer drinks. The thin, woody, brown-grey roots carry a warm, sweetly balsamic scent, often compared to vanilla and root beer, that comes largely from the compound 2-hydroxy-4-methoxybenzaldehyde. Simmered with sugar and spices into a deep ruby-red syrup, then let down with cold water, lime and sometimes milk, nannari becomes the classic sharbat sold from summer stalls across Tamil Nadu, Kerala and Andhra Pradesh — a drink prized in the region's traditional medicine as a "body coolant" for the hot months. It is entirely distinct from the true sarsaparilla (Smilax) of the Americas, though the two share a similar sweet-woody, root-beer character and both once flavoured old-fashioned tonics.