Substitutes:

• Rhubarb Liqueur: If you don't have rhubarb liqueur, try using an elderflower liqueur for a floral twist. I've also used raspberry liqueur for a fruitier profile.
• Mezcal: If you prefer a less smoky flavor, substitute mezcal with tequila. It still gives that agave essence without the smokiness.
• Fresh Lemon Juice: Bottled lemon juice works in a pinch, but I always find fresh lemon juice gives the best flavor.
• Celery Bitters: If you can't find celery bitters, use Angostura bitters for a more traditional bitter note.
• Sugar Syrup: You can make your own sugar syrup by dissolving equal parts sugar and water over low heat until thoroughly combined.

Making a Pitcher of Garden Sour:

• Scale: To make a pitcher that serves 8, multiply all the ingredients by 8. That would be 8 oz of rhubarb liqueur, 8 oz of mezcal, 6 oz of fresh lemon juice, 16 dashes of celery bitters, and 4 oz of sugar syrup.
• Mix: In a large pitcher, combine the rhubarb liqueur, mezcal, fresh lemon juice, celery bitters, and sugar syrup. Stir well.
• Serve: Pour the mixture into individual ice-filled Old Fashioned glasses, garnish with a lemon twist or slice, and serve immediately.

Making it Non-Alcoholic:

• Rhubarb Liqueur Substitute: Use a rhubarb syrup or cordial to mimic the flavor without the alcohol.
• Mezcal Substitute: Opt for a non-alcoholic spirit that mimics the smoky flavor of mezcal, or use smoked tea (like lapsang souchong) brewed strong and chilled.
• Proceed As Usual: Use these non-alcoholic substitutes instead of the regular ingredients, follow the original steps, and enjoy a non-alcoholic version.