The Chemistry of Olive Oil Grades in Soapmaking: Extra Virgin vs Virgin vs Pomace

Olive oil is one of the most beloved ingredients in natural cold process soap. It creates a gentle, conditioning bar that has been prized for centuries. But not all olive oils behave the same way in the soap pot. Many soapmakers notice that virgin and especially pomace olive oils trace much faster than extra virgin olive oil — sometimes catching them off guard. Let’s explore the science behind these differences and how you can work with each type successfully.

Understanding Olive Oil Grades

Olive oils are classified into different grades based on how they are extracted and their chemical composition:

• Extra Virgin Olive Oil (EVOO)

  • Extracted mechanically, no heat or chemicals.

  • Low free fatty acid (FFA) content: ≤0.8%.

  • High antioxidants, polyphenols, and unsaponifiables.

  • Slower to trace in soapmaking.

• Virgin Olive Oil

  • Also extracted mechanically, but from slightly lower-quality fruit or with less stringent processing.

  • Higher FFA content: ≤2.0%.

  • Fewer stabilizing antioxidants compared to EVOO.

  • Traces more quickly than EVOO.

• Pomace Olive Oil

  • Extracted from olive pulp and pits using heat and solvents.

  • Very high FFA before refining, typically reduced during refinement.

  • Very low antioxidants and unsaponifiables.

  • Known for very fast trace.

Why Trace Happens Faster with Virgin and Pomace Oils

In cold process soapmaking, trace is the point when oils and lye solution emulsify and begin turning into soap. The first soap molecules formed act as natural emulsifiers, thickening the batter.

The speed of trace depends largely on fatty acid chemistry:

1. Free Fatty Acids (FFA)

   • Free fatty acids react instantly with sodium hydroxide (NaOH).

   • Virgin olive oil contains more FFAs than EVOO, and pomace even more — meaning soap formation starts much faster.

2. Fatty Acid Profile

   • EVOO is very high in oleic acid (~70–75%), which saponifies slowly.

   • Virgin and pomace oils have slightly more palmitic and stearic acids (saturated fats), which accelerate thickening.

3. Antioxidants and Unsaponifiables

   • EVOO is rich in antioxidants and polyphenols, which act as natural buffers, slightly slowing emulsification.

   • Virgin has less, and pomace has almost none — so there’s nothing to slow down the reaction.

Visual Comparison

Below is a chart showing free fatty acidity (FFA) levels for each oil and how they correlate with relative trace speed:

• Extra Virgin Olive Oil → Low FFA, slowest trace.

• Virgin Olive Oil → Moderate FFA, medium trace.

• Pomace Olive Oil → High FFA, fastest trace.

Tips for Working with Each Olive Oil

Extra Virgin Olive Oil

• Best for designs requiring long working time (swirls, layers).

• Soap stays fluid, but curing may take longer to achieve hardness.

• Ideal for Castile soaps.

Virgin Olive Oil

• Expect a medium-speed trace.

• Tips to slow down trace:

  • Soap at cooler temperatures (30–35°C / 85–95°F).

  • Use full water (no discounts).

  • Stick-blend only to light emulsion, then stir by hand.

  • Avoid accelerating fragrance oils (spices, florals, citrus).

Pomace Olive Oil

• Traces very quickly — excellent for simple, single-color soaps.

• Tips to manage fast trace:

  • Work at low temperatures (around 30°C).

  • Add fragrance and botanicals after light trace.

  • Keep designs simple — fast trace limits intricate patterns.

  • Consider blending with slower oils (like high oleic sunflower) to extend working time.

The difference between extra virgin, virgin, and pomace olive oils comes down to their chemistry: free fatty acid content, fatty acid balance, and antioxidant levels. These factors directly influence how quickly your soap batter thickens at trace.

• EVOO = slow and fluid.

• Virgin = faster, manageable with care.

• Pomace = lightning-fast, best for simple pours.

By understanding the science and adjusting your technique, you can harness the unique properties of each olive oil grade and craft beautiful, consistent natural soaps.