Shower Steamers with Menthol Crystals

Shower steamers are effervescent aromatherapy tablets that release menthol vapors in hot shower steam. These vapors provide respiratory relief and a refreshing spa-like experience. This project combines simple chemistry with cosmetic formulation to create a customizable wellness product.

What You'll Need

  • 1 cup baking soda (sodium bicarbonate)
  • ½ cup citric acid
  • ¼ cup cornstarch
  • 2–4 tbsp menthol crystals (adjust for intensity)
  • 1–2 tbsp carrier oil (coconut, jojoba, or almond)
  • Essential oils (optional: eucalyptus, lavender, peppermint, etc.)
  • Water in spray bottle (minimal amount)
  • Silicone molds, mixing bowl, gloves, spatula
  • Mortar and pestle or ziplock bag (to crush menthol)

The Process

  1. Prepare workspace: Clean and dry all tools and wear gloves to handle menthol crystals safely.
  2. Crush menthol crystals: Break into smaller granules for even distribution.
  3. Mix dry ingredients: Combine baking soda, citric acid, and cornstarch until uniform.
  4. Add menthol crystals: Stir evenly into dry mixture.
  5. Add carrier oil and essential oils: Mix thoroughly to distribute aroma and moisture.
  6. Spray water slowly: Add 1–2 sprays at a time, mixing immediately to avoid premature fizzing. Stop when the texture clumps like damp sand.
  7. Pack molds: Press mixture firmly into silicone molds; smooth tops.
  8. Drying: Let sit undisturbed for 24–48 hours until completely hardened.
  9. Store: Keep in airtight containers away from humidity. Add silica gel packets if available.

How to Use

  1. Place one tablet on the shower floor, away from direct water flow.
  2. Turn on hot water to generate steam and activate the steamer gradually.
  3. Inhale deeply for 5–15 minutes for full aromatic effect.

Popular Variations

  • Spa Morning: Eucalyptus, lemon, and rosemary oils – energizing and refreshing.
  • Evening Calm: Lavender and chamomile – for relaxation and stress relief.
  • Cold & Flu Fighter: Eucalyptus, peppermint, and tea tree – for congestion relief.

Scientific Background

Effervescence results from the reaction between baking soda and citric acid when water activates them:

3NaHCO₃ + C₆H₈O₇ → C₆H₅Na₃O₇ + 3H₂O + 3CO₂

This reaction releases carbon dioxide bubbles and mild heat, helping vaporize menthol. The vapors stimulate TRPM8 receptors, producing a cooling, decongestant sensation and promoting easier breathing.

Safety Notes

  • Wear gloves when handling menthol crystals and citric acid.
  • Do not place tablets directly under the water stream—they will dissolve too fast.
  • Keep away from eyes and children; for external use only.
  • Ensure bathroom ventilation and discontinue use if irritation occurs.