Gentian is a root unearthed in volcanic soil in France. Its bittersweet flavor is very popular in France, sold as liqueurs and apéritifs; Suze, Salers, and Avèze are the most well-known. If you’re in France, Distillerie de Grandmont makes an excellent artisan gentian liqueur that I like very much, but isn’t widely available. (Google it to track a bottle down from online sellers.) Also in France is Ziane, a non-alcoholic gentian apéritif, and another one made by Couderc distillery, whose website I can’t figure out how to navigate. Both would work if you’d like to make this a mocktail.
While some people find gentian-based spirits rather strong, in this gentle fizz, the bitterness is tempered by the pineapple juice and cold tonic water. All that’s needed to finish it up is a flurry of fresh mint on top, and a straw.