Additives change how a bar looks, feels and lathers. Start small. The amounts below are starting points from established soap suppliers and teachers, so adjust them in small test batches.

Additives chart (cold process)

"PPO" means per pound of oils.

Sodium lactate

• Starting amount: 1 tsp PPO

• What it's for: Harder bar that unmolds sooner. Too much can make it crumbly.

• When to add it: Stir into lye water cooled to 130°F or below

Sugar

• Starting amount: ½ tsp PPO

• What it's for: Bigger lather

• When to add it: Dissolve in warm lye water

Salt

• Starting amount: ½–1 tsp PPO

• What it's for: Harder bar

• When to add it: Dissolve in hot lye water

Silk fibers

• Starting amount: A pea-sized pinch PPO

• What it's for: Silky slip

• When to add it: Dissolve in hot lye water

Honey

• Starting amount: 1 tbsp PPO

• What it's for: Lather. It can speed trace or overheat.

• When to add it: Mix into warm oils

Milk powder (goat, buttermilk, coconut)

• Starting amount: 1 tbsp PPO

• What it's for: Creamy lather

• When to add it: Mix into the oils

Clay (kaolin and others)

• Starting amount: 1 tsp PPO

• What it's for: Natural color and light exfoliation

• When to add it: In the lye water or at trace. Disperse it in water first.

Activated charcoal

• Starting amount: 1 tsp–1 tbsp PPO

• What it's for: Gray to black color

• When to add it: Mix into the oils

Cocoa powder

• Starting amount: 1 tbsp PPO

• What it's for: Brown color

• When to add it: Mix into warm oils

Oatmeal (ground)

• Starting amount: 1 tbsp PPO

• What it's for: Gentle exfoliation. Grind it finer for less scrub.

• When to add it: Mix into the oils

Coffee grounds

• Starting amount: 1 tbsp PPO

• What it's for: Exfoliation and color

• When to add it: Mix into the oils

Poppy seeds or fruit seeds

• Starting amount: 1 tsp PPO

• What it's for: Exfoliation and speckles

• When to add it: Mix into the oils

Cornmeal

• Starting amount: 1 tsp PPO

• What it's for: Exfoliation

• When to add it: Mix into the oils

Dried herbs and flowers

• Starting amount: 1 tsp PPO

• What it's for: Looks and texture. Most turn brown or black in soap, but calendula stays yellow.

• When to add it: Mix into the oils, or sprinkle on top

Aloe powder

• Starting amount: ½ tsp PPO

• What it's for: Slip

• When to add it: Mix into the oils

Beeswax

• Starting amount: 1–3% of oils (Bramble Berry allows up to 8%)

• What it's for: Hardness. It speeds trace, and too much feels draggy.

• When to add it: Melt with the hard oils

No health claims. Additives like oatmeal or charcoal are about look and feel. Calling a soap a treatment for a skin condition makes it a drug in the eyes of the FDA (FDA: Frequently Asked Questions on Soap).

Fragrance and essential oils

• Use only skin-safe oils that are labeled for soap. Fragrance oils that aren't made for cold process are the most common cause of ricing and seizing.

• Check the IFRA certificate. Each fragrance oil has a maximum use level for each product type. Bar and liquid soap fall under IFRA Category 9. Your supplier publishes the number. Stay under it.

• Starting amounts: Bramble Berry suggests 0.7 oz per pound of soap batch for a strong scent in cold process, 0.4 oz for rebatch and 0.3 oz for melt and pour. Many other suppliers give 3–6% of the oil weight. Check which weight a rate refers to before you compare.

• Essential oils are concentrated plant oils with their own limits, and some are much lower than fragrance oils. Follow your supplier's IFRA or usage data for each one.

• Citrus and coconut scents often fade in cold process. Lemon works better in melt and pour.

• Weigh fragrance. A fluid ounce isn't a weight ounce.

Colorants

• Micas: shimmery powders. Many change color or fade in cold process, so test first. Soap Queen starts at about 2 tsp per pound.

• Oxides and ultramarines: strong pigments. A little goes a long way. Too much, especially of black or red oxide, can tint the lather and washcloths.

• Disperse colors first: mix 1 tsp of colorant into 1 tbsp of a light oil (like sweet almond), then add about 1 tsp of the mixture per pound of soap, a little at a time.

• Clays, charcoal, cocoa and spices give natural shades (see the chart above).

• Melt and pour: check that your colorant is labeled for melt and pour, since some behave differently there.

Sources - FDA: Frequently Asked Questions on Soap (claims that make a soap a cosmetic or drug). https://www.fda.gov/cosmetics/cosmetic-products/frequently-asked-questions-soap - Lovin Soap Studio: Soapmaking Additive Chart (starting amounts and when to add). https://lovinsoap.com/soapmaking-additive-chart/ - Soap Queen: How to Use Sodium Lactate (1 tsp PPO in lye water at 130°F or below; too much is crumbly). https://soapqueen.com/bath-and-body-tutorials/sunday-night-spotlight-sodium-lactate/ - Bramble Berry: Beginner's Guide to Common Soap Making Oils (beeswax up to 8%, speeds trace). https://www.brambleberry.com/beginner/beginners-guide-to-common-soapmaking-oils.html - Bramble Berry: Using the Fragrance Calculator (0.7 / 0.4 / 0.3 oz per lb). https://www.brambleberry.com/bath-and-body/using-fragrance-calculator.html - Bramble Berry: How to Prevent Scent Fading in Soap (citrus and coconut fade; IFRA/RIFM limits). https://www.brambleberry.com/soap/scent-fading.html - IFRA Standards Library (Category 9: rinse-off body products including soap). https://ifrafragrance.org/standards-library - Soap Ledger: Fragrance usage rates and IFRA (3–6% of oils supplier range). https://soapledger.com/guides/fragrance-usage-rates-and-ifra/ - Soap Queen: How to Color Handmade Soap (1 tsp to 1 tbsp oil; about 1 tsp per lb). https://soapqueen.com/magicpod/color-handmade-soap/ - Soap Queen: Sunday Night Spotlight: Mica Colorants (2 tsp per lb starting point, test for morphing). https://soapqueen.com/bath-and-body-tutorials/tips-and-tricks/sunday-night-spotlight-mica-colorants/ - Soap Queen: Soapy Mess-Up Quick Guide (ricing/seizing from fragrance; too much colorant colors lather). https://soapqueen.com/bath-and-body-tutorials/tips-and-tricks/soapy-mess-quick-guide/ - Soap Queen: How to Use Clay in Bath & Beauty Projects (disperse in water). https://soapqueen.com/magicpod/use-clay-bath-beauty-projects/