Fill a highball glass to the top with ice.
Add the NA bitter aperitif and fresh grapefruit juice directly over the ice.
Top with dry tonic water.
Gently pull the drink together once or twice with a barspoon to integrate without losing carbonation.
Garnish with a grapefruit slice on the rim.
Using a proper dry tonic water here is non-negotiable - a standard or Mediterranean tonic will introduce unwanted sweetness that undermines the drink's entire character. Fever-Tree Refreshingly Light or East Imperial Dry tonic are ideal choices.
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