Before we start making liquid Castile soap, it’s crucial to have the right tools and understand proper safety measures—especially when handling potassium hydroxide (KOH). This lesson will cover the essential tools needed for soap making and critical safety precautions to ensure a safe and successful soap-making experience.

Link to Ingredients and Tools you will need for this class

Essential Tools for Liquid Castile Soap Making

Having the right tools ensures accurate measurements, proper blending, and safe handling of ingredients. Below is a list of must-have equipment for making liquid Castile soap.

1. Digital Scale

• Why? Precise measurements are essential for soap-making chemistry.
• Tip: Always weigh your ingredients rather than using volume measurements (e.g., cups or spoons).

2. Crockpot (Slow Cooker)

• Used for hot process soap making, which helps speed up saponification.
• Keeps the soap mixture at a consistent, controlled temperature.

3. Stick Blender (Immersion Blender)

• Blends the oils and lye mixture quickly and efficiently.
• Helps reach “trace” (the stage where oils and lye fully combine) faster.
• Tip: Use a dedicated stick blender for soap making—do not reuse for food preparation.

4. Heat-Resistant Mixing Bowls

• Used to hold and mix oils and lye solutions.
• Best materials: Stainless steel, heat-resistant plastic, or tempered glass.
• Avoid: Aluminum or non-tempered glass, as they can react with lye or shatter under heat.

5. Large Glass or Plastic Measuring Cups

• Used for measuring liquids like water, oils, and diluted soap.
• Tip: Choose heat-resistant plastic or glass to withstand lye solutions.

6. Long-Handled Spoon (Stainless Steel or Silicone)

• Used for stirring the soap mixture.
• Best materials: Stainless steel or heat-resistant silicone.
• Avoid: Wooden spoons, as they can absorb lye and become unsafe for future use.

7. Thermometer

• Used to check the temperature of oils and lye solution before mixing.
• Ideal range: Oils and lye should be between 120°F – 140°F (49°C – 60°C) before combining.

8. Soap pH Strips

• Used to test the pH level of the finished soap.
• Ideal pH for liquid Castile soap: 9 to 10 (safe for skin but still cleansing).

9. Bottles for Storing Liquid Soap

• Choose plastic pump bottles, glass jars, or recycled soap dispensers.
• Tip: If using essential oils, store in dark glass bottles to preserve fragrance.

💡 Pro Tip: Save money by sourcing your soap-making tools from thrift stores, estate sales, or discount shops! Many second-hand stores carry stainless steel bowls, measuring cups, spoons, slow cookers, and stick blenders at a fraction of retail prices. Look for heat-resistant glass, stainless steel, and silicone materials, and dedicate these tools for soap-making only. Bonus: Buying second-hand is not just budget-friendly—it’s also eco-friendly! ♻️

Safety Precautions When Making Liquid Castile Soap

Soap making involves working with potassium hydroxide (KOH), which is a strong alkaline substance. Proper safety measures are essential to prevent burns, spills, and chemical reactions.

1. Proper Handling of Potassium Hydroxide (KOH)

⚠️ KOH is highly caustic and can cause severe burns if it comes into contact with skin.
✅ Always measure KOH carefully using a digital scale—never estimate.
✅ Use heat-resistant plastic or glass containers when mixing with water (avoid metal).
✅ Never touch KOH with bare hands—always wear gloves.

2. Importance of Wearing Protective Gear

🧤 Gloves: Protects hands from KOH burns and irritation.
👓 Safety Goggles: Prevents lye splashes from getting into your eyes.
👕 Long-Sleeved Shirt & Pants: Prevents lye or soap from contacting your skin.
💨 Ventilation: Work in a well-ventilated area or near an open window to avoid inhaling fumes.

3. How to Safely Mix Lye with Water

Mixing potassium hydroxide (KOH) with water generates heat and can cause dangerous reactions if not done correctly. Follow these steps to mix safely:

1️⃣ ALWAYS add KOH to water—NEVER the other way around.

• If you pour water onto KOH, it can cause a violent reaction, producing steam and splattering.

2️⃣ Use a heat-resistant container.

• The mixture will become very hot (up to 200°F/93°C) and may crack weak containers.

3️⃣ Mix in a well-ventilated area.

• The reaction creates strong fumes, so keep your face away and ensure good airflow.

4️⃣ Stir gently until fully dissolved.

• Do not inhale the fumes; they will dissipate within a few minutes.

5️⃣ Let the lye solution cool before use.

• The ideal mixing temperature is 120°F – 140°F (49°C – 60°C).

💡 Pro Tip: Label all soap-making containers and tools “For Soap Making Only” to prevent accidental use for food.

 

Key Takeaways from This Lesson

✅ Gather all essential tools before starting to ensure smooth and safe soap making.
✅ Always use a digital scale for accurate ingredient measurements.
✅ Wear protective gear (gloves, goggles, and long sleeves) to prevent lye burns.
✅ NEVER add water to KOH—always add KOH to water to avoid dangerous reactions.
✅ Mix lye in a well-ventilated area and let it cool before combining with oils.

 

Next Lesson: The Soap-Making Process

Now that we have our tools and safety precautions in place, we’re ready to start making liquid Castile soap!

🔹 Step-by-step instructions for mixing lye and oils
🔹 Understanding “trace” and saponification
🔹 Cooking and diluting the soap paste

➡️ See you in the next lesson! 🎉