The Butterfly Mule is a classic Moscow Mule with a visual twist — serve it from the keg and finish each glass with a 1 oz float of Top Hat Butterfly Truth Serum at service. The indigo butterfly pea flower extract reacts with the citrus in the mule and shifts from deep blue to purple-pink before guests' eyes. One of the most talked-about pours you can run on draft.
The color-change float is the entire show — batch the mule on CO₂ for a clean, crisp ginger-lime base, then finish each pour with a slow float of Butterfly Truth Serum. The pH shift from the lime juice triggers the color change instantly. This is what a bar program that people photograph looks like.
Batch Method
- Add 5 liters vodka to a clean 5-gallon Cornelius keg.
- Add 3 qts Top Hat Original Ginger Beer Syrup.
- Add 12 oz fresh lime juice if using.
- Add 11 qts cold filtered water.
- Seal the keg and shake vigorously side to side for 2 full minutes.
- Carbonate with CO₂. See instructions below.
- Refrigerate minimum 12 hours before first service.
- Pour ~6 oz over ice into each glass. Garnish with sliced lime and fresh mint.
- Float 1 oz Butterfly Truth Serum over the back of a bar spoon onto each pour at service — watch the color shift.
- Reshake twice daily to re-integrate ingredients.
Pro move: The color-change reaction is pH-driven — the citrus in the mule triggers the shift from indigo blue to purple-pink the moment the Butterfly Truth Serum hits the drink. Add the lime juice to the keg to guarantee the reaction is consistent every pour. Float the Butterfly Truth Serum slowly over the back of a bar spoon so it sits on top before mixing — guests get the full visual before they take their first sip.
- Insert charging stone lid at 45° and spin to align seal. Clamp firmly closed.
- Set CO₂ regulator to 20–25 psi.
- Connect gray/silver Cornelius connector to center plug of charging stone lid.
- Pull up pressure release ring 30 times quickly. Release between each pull.
- Refrigerate 24 hours. Cold liquid absorbs carbonation better.
- Once cold: pull pressure release ring 30 more times.
- Test flow. Reduce to 15 psi if foamy. Maintain 20–25 psi without foam.