Mescal has a smoky herbaceous flavour; substitute tequila for a cleaner-tasting result.
120 mlmescal or tequila600 mlpink grapefruit juice, plus thickly sliced pink grapefruit, to serve200 mlsoda, or to tasteTo serve:lime wedgesLime-salt rimFinelygrated rind of 1 lime1 tbspsea salt1 tspcaster sugar
For lime-salt rim, pound ingredients in a mortar and pestle to just combine, transfer to a plate and set aside.
Rub rims of tumblers with a slice of grapefruit to moisten and dip tumbler rims into lime-salt, pressing lightly, then fill tumblers with ice. Divide mescal and juice among tumblers, top with soda, add a squeeze of lime, garnish with a slice of grapefruit and serve.