Mojito Bubbles (molecular gastronomy)

Image-templateWhy go for the stock standard cocktail when you can easily add a science twist?


  • slotted spoon (buy here)
  • measuring spoons
  • 3 containers
  • muddler
  • sieve
  • silicon round base ice tray (buy here)
  • stick blender
  • fridge and freezer
  • Chinese soup spoons for serving


  • 45mL white rum
  • 60mL soda water
  • 12 mint leaves
  • 1/3 lime sliced in wedges
  • 1 tsp sugar
  • 1/4 tsp calcium lactate (buy here)
  • 1tsp sodium alginate (buy here)
  • 1L filtered water
  • extra mint leaves (or parts of leaves) to freeze in cocktails

day before

  1. Place sugar, calcium lactate, lime wedges and mint leaves into a container.
  2. Muddle and crush together to release lime juice and bruise mint leaves.
  3. To this mix add rum and soda water and combine well.
  4. Taste – add more lime or sugar (or booze!) as desired.
  5. To each cube reservoir in the ice cube tray, add small pieces of extra mint leaf. These will freeze in the cocktail and then float inside the bubble once you serve it.
  6. Strain through sieve and pour cocktail mix onto mint leaves into silicon ice cube tray.
  7. Freeze cocktail mix. Note that the ice blocks map appear to not freeze solid due to bubbles from the soda. However, freeze for as long as possible as it will make your job easier later.

Before serving

  1. Make sodium alginate bath by adding sodium alginate powder to 500mL filtered water and mix well with stick blender.
  2. Set aside to thicken in fridge for around 15 minutes.
  3. Remove thickened liquid from fridge and gently unmold cocktail ice blocks into sodium alginate bath.
  4. Do this one at a time so ice blocks do not touch – if they touch they will stick to each other.
  5. Set aside for 3 minutes. Stirring gently several times to ensure all sides of the ice block come in contact with the sodium alginate bath.
  6. Carefully remove balls using slotted spoon and rinse in bowl filled with filtered water.
  7. Drain and place into serving spoon. If required, soak up any water surrounding the bubble with paper towel.
  8. Best served immediately.

For further tips on this technique, click here.

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