1. Prep the Glass: Rub a lime wedge around the rim of a highball glass and dip it into a plate of Tajín or salt. Fill the glass with fresh ice.
2. Combine: In a shaker (or directly in the glass if you're keeping it casual), combine the Entropía 22 Mezcal, grapefruit juice, lime juice, and agave nectar.
3. Shake (Quickly): Shake with ice for just 5–10 seconds. You just want to chill and integrate the citrus.
4. Strain & Top: Strain into your prepared highball glass. Top it off with the soda water.
5. Stir: Give it one very gentle stir to pull the flavours together without killing the bubbles.
6. Garnish: A fresh grapefruit wedge or a dehydrated grapefruit wheel.