Soap Additives Guide
Clays, Honey, Oatmeal, Botanicals & More
What Are Soap Additives?
Additives are extra ingredients added to your soap recipe beyond the basic oils, lye, and water. They can provide color, exfoliation, lather boosting, hardness, and special properties. While completely optional, additives let you create unique, customized soaps.
Common Purposes:
- Colorants: Clays, charcoal, cocoa, botanicals
- Exfoliants: Oatmeal, poppy seeds, coffee grounds
- Lather Boosters: Honey, sugar, sodium lactate
- Hardeners: Salt, beeswax, sodium lactate
- Skin Benefits: Aloe, silk, milk powders
Adding Additives in the Calculator
The SoapMath calculator includes 20+ common additives with built-in usage rates:
- Navigate to Step 5: Additives, Colorants & Water Replacements
- Check the box "I want to input additives"
- Select an additive from the dropdown menu
- Choose your measurement method: tsp, tbsp, weight, or % of oils
- Enter your amount - the calculator converts to weight automatically
- Add multiple additives by selecting more from the dropdown
Usage Rates: Most additives are measured per pound of oils. The calculator's default amounts are based on the Lovin Soap additive chart - a trusted soapmaking reference.
Clays
Clays add natural color and can provide gentle exfoliation. They also help anchor scents and add slip to shaving soaps.
| Clay Type | Color | Usage Rate | Properties |
|---|---|---|---|
| Kaolin (White) | White/cream | 1 tsp/lb oils | Mildest; great for sensitive skin; slip for shaving |
| Bentonite | Gray-green | 1 tsp/lb oils | Drawing; good for oily skin; excellent for shaving soap |
| French Green | Sage green | 1 tsp/lb oils | Mineral-rich; suitable for all skin types |
| Rose/Pink | Soft pink | 1 tsp/lb oils | Gentle; great for sensitive and mature skin |
| Rhassoul | Brown | 1 tsp/lb oils | Moroccan; conditioning; reduces dryness |
How to Add: Mix clay with a small amount of oil or water to create a slurry before adding at trace. This prevents clumping.
Lather Boosters & Hardeners
| Additive | Usage Rate | Purpose | When to Add |
|---|---|---|---|
| Honey | 1 tbsp/lb oils | Lather boost, humectant, golden color | At trace; watch for overheating! |
| Sodium Lactate | 1 tsp/lb oils | Hardness, faster unmold, silkiness | Add to cooled lye water |
| Salt | 0.5 tsp/lb oils | Hardness (small amounts) | Dissolve in water phase |
| Beeswax | 2% of oils | Hardness, longevity | Melt with oils; adds to SAP |
| Sugar | 1 tsp/lb oils | Lather boost | Dissolve in water phase |
Sugar Warning:
Honey and sugar increase saponification heat. Don't insulate sugar/honey soaps. Put in refrigerator or freezer if soap starts to volcano.
Exfoliants & Botanicals
| Additive | Usage Rate | Exfoliation Level | Notes |
|---|---|---|---|
| Colloidal Oatmeal | 1 tbsp/lb oils | Gentle | Soothing, great for sensitive skin |
| Poppy Seeds | 1 tsp/lb oils | Medium | Classic look, effective scrub |
| Coffee Grounds | 1 tbsp/lb oils | Medium-Strong | Use dried, spent grounds; adds brown color |
| Corn Meal | 1 tsp/lb oils | Medium | Good for gardener's/mechanic's soap |
| Lavender Buds | 1 tsp/lb oils | Gentle | Decorative; turns brown in soap |
| Calendula Petals | 1 tsp/lb oils | Gentle | Stays yellow! One of few botanicals that keep color |
| Orange Peel Powder | 1 tsp/lb oils | Medium | Adds orange-brown color and light citrus scent |
Botanicals in Soap:
Most flowers and herbs turn brown in cold process soap due to the high pH. Calendula is a notable exception. For decorative botanicals, add them on top of the soap rather than mixing in.
Special Purpose Additives
| Additive | Usage Rate | Purpose |
|---|---|---|
| Activated Charcoal | 1 tsp/lb oils | Deep gray-black color; drawing properties; popular for facial bars |
| Cocoa Powder | 1 tbsp/lb oils | Brown color; subtle chocolate scent; pairs with coffee FO |
| Silk Fibers | 0.5 tsp/lb oils | Silkiness, slip, luxurious feel; dissolve in lye water |
| Aloe Powder | 0.5 tsp/lb oils | Soothing; good for sensitive skin formulas |
| Milk Powders | 1 tbsp/lb oils | Creaminess, lather boost; easier than liquid milk |
When to Add Additives
Add to Lye Water (before mixing):
Sodium lactate, silk fibers, salt, sugar
Add to Oils (before mixing):
Beeswax (melt with oils), milk powders
Add at Light Trace:
Clays (as slurry), honey, charcoal, cocoa powder
Add at Medium Trace:
Exfoliants (oatmeal, seeds, grounds), botanicals
Troubleshooting Additives
| If you see this... | What's happening... | Solution |
|---|---|---|
| Clumps of clay | Clay wasn't dispersed before adding | Mix clay with oil or water to make slurry first; add at thin trace and blend well |
| Soap overheated with honey | Sugars caused excess heat | Don't insulate; refrigerate or freeze immediately; reduce honey next batch |
| Botanicals turned brown | Normal reaction with high pH | Use calendula (stays yellow); add dried botanicals on top only; accept the rustic look |
| Exfoliants sank to bottom | Added at too thin trace | Add at medium-thick trace so batter holds particles suspended |
| Soap is too scratchy | Too much exfoliant or particles too coarse | Reduce amount; grind ingredients finer; switch to gentler option like oatmeal |
| Charcoal made gray streaks | Not mixed thoroughly | Mix charcoal with oil first; add at thin trace; stick blend thoroughly |