Soap Additives: Honey, Clays, Silk, Oatmeal and More

TL;DR: Additives modify the properties of soap - honey speeds up production and adds color, clays cleanse oily skin, silk increases the feeling of luxury. Basic rule: gradually on trace, max 1-2 tablespoons per 500 g of oils. Try gradually - each ingredient will change the temperature or consistency.

Additives are ingredients added to soap beyond the basic formula (oils + lye + water) that modify the resulting properties - skin feel, lather, conditioning, scent or appearance. Each ingredient brings a trade-off: benefits vs. durability vs. complexity of production.

This encyclopedia covers the most commonly used ingredients with precise dosages, addition techniques and scientific explanations of function.

Honey: humectant and temperature accelerator

Honey is a hygroscopic substance - it attracts and binds moisture. In soap it acts as a humectant and contributes to the feeling of softness after washing. It contains natural sugars (glucose, fructose) and enzymes that accelerate saponification in an alkaline process - honey is one of the most significant temperature accelerators in soap. A batch with honey can reach 65-70°C during the gel phase.

Practical effect: Golden to caramel colour of soap (Maillard reaction of sugars on heating). Gentle conditioning sensation. Contributes to a thicker, creamier lather.

How to add:

• Add honey to the light trace - never to the lye or to the leaching solution
• Amount: 1-2 tablespoons (20-40 g) per 500 g of oils
• Higher quantity = stronger temperature acceleration, higher risk of overheating

Overheating warning: Honey significantly increases the temperature of the process. Put the mold after filling in the refrigerator or a chilled room (not in the heat). Avoid the gel stage by covering - or conversely, fully gel in the heat, but monitor the temperature.

Suitable combinations: Honey + oatmeal + milk = classic dry skin care.

Oatmeal: exfoliation and soothing

Oatmeal is one of the oldest and best-studied ingredients in skin care. They contain beta-glucans (moisturizing polysaccharides), avenatonthramides (anti-inflammatory agents) and flavonoids. In the soap they create a gentle exfoliating effect and leave a protective film - suitable for sensitive and atopic skin.

Soap molds:

• Colloidal oatmeal: Very finely ground, homogeneous in soap. Best for delicate skin. Available as cosmetic raw material.
• Finely ground oatmeal: Semolina texture - visible and tactile. Grind at home in a coffee grinder or food processor.
• Whole flakes: Strong exfoliation, visible texture, rustic look. Suitable for feet or rougher skin.

Dosage: 2-4 tablespoons per 500 g of oils. For colloidal oatmeal 1-2 tablespoons. Add to trace as a powder or premixed in a small amount of oil.

The appearance of finished soap: Beige to caramel colour, flakes visible (in the coarse form). With honey they give a classic "oatmeal“ look.

Clays: cleansing by skin type

Clays are mineral additives with adsorptive properties - they attract and bind impurities, excess sebum and toxins. There are different groups for different skin types.

Kaolin (white clay)

The finest and gentlest clay. Low adsorption capacity - suitable for dry and normal skin. Adds a silky feel and slight slip (slipperiness when shaving).

Dosage: 1-2 tablespoons per 500 g of oils. Add premixed in oil to trace.

French Green Clay

High adsorption capacity - for oily and acne-prone skin. Colouring: olive green soap colour (stable). Detoxifying effect for skin with enlarged pores.

Dosage: 1 tablespoon per 500 g of oils.

Bentonite

Volcanic clay with exceptional adsorption capacity. Binds heavy metals and toxins. Accelerates trace in soap - test consistency and add to light trace. Suitable for shaving soaps (adds slip).

Dosage: 1 teaspoon per 500 g of oils - more speeds up the trace.

Rhassoul clay (Ghassoul)

Moroccan clay from aluminous layers. Conditioning and cleansing at the same time. Dark brown colour. Ideal for hair and skin - traditional hammam ingredient.

Dosage: 1 tablespoon per 500 g of oils.

Red clay (Red Kaolin)

Soft pink to reddish brown colour. Medium adsorption. For normal to sensitive skin. Adds colour and minerals.

Silk: luxurious feel and shine

Silk - protein fibres from silkworms - is added to soap in the form of short fibres or hydrolysed silk protein. Hydrolysed silk protein binds to the surface of the skin and hair, leaving a protective film - a feeling of smoothness and shine.

How to add:

• Silk fibers (silk fibers, tussah silk): Add a small pinch (0.5-1 g per 500 g of oils) directly into the hot lye solution - the lye will dissolve the fibres. The solution turns golden and smells a little - normal. Alternatively, add the fibres to the water before adding the lye.
• Hydrolyzed silk protein (liquid): Add directly to the trace. Amount: 5-10 ml per 500 g of oils.

Note: The silk fibres in the lye release amino acids - the soap then lathers better and has an absorbent feel. Do not confuse with silk cloth - it does not dissolve.

Panthenol: conditioning and healing

Panthenol (D-panthenol, provitamin B5) is a conditioning ingredient with a proven function in cosmetics. In the skin, it is converted into pantothenic acid (vitamin B5), which promotes regeneration. A humectant that binds moisture, soothes and promotes healing of minor skin injuries - a popular ingredient in soaps for sensitive skin and shampoo bars.

Forms:

• Liquid panthenol: 75% or 50% solution in water. Add per trace - 1-3% of the total weight of oils.
• Panthenol DL powder: less common but more durable.

Dosage: 1-2% of the total weight of the oils (5-10 g per 500 g of oils). Add to the trace.

Vitamin E: antioxidant and shelf life

Vitamin E (alpha-tocopherol or mixed tocopherols) is a natural antioxidant. In soap, it primarily serves the function of extending shelf life - it slows down the oxidation of unsaponified oils and thus delays rancidity (DOS - dreaded orange spots). It does not extend shelf life indefinitely - it is an antioxidant, not a preservative.

Dosage: 0.5-1% of the total weight of the oils. Add to the trace along with the essential oils.

Note: Vitamin E does not work against bacteria or fungi.

Rosemary oleoresin extract (ROE): potent antioxidant

ROE (Rosemary Oleoresin Extract) is a highly concentrated natural antioxidant from rosemary. Effective for preventing oxidation of polyunsaturated oils (linseed, hemp, sunflower) - more potent than vitamin E. Has a distinctive herbal rosemary scent that is almost imperceptible in the finished soap.

Dosage: 0,1-0,5 % of the total weight of the oils. Add to oils before adding lye or on trace.

Activated charcoal: detox and black color

Activated charcoal adsorption ability binds dirt and excess sebum. See separate guide: Activated charcoal soap.

Briefly: dosage 1 tsp/500g for black soap, 0.5 tsp for dark grey. Add to trace in oil.

Sodium lactate: faster unmolding

Sodium lactate is the sodium salt of lactic acid. Added to the leaching solution, it accelerates the setting of the soap - the soap can be removed from the moulds earlier (12-18 h instead of 24-48 h). Mechanism: sodium lactate reduces the free water content of soap and accelerates the crystallization of stearate salts.

Dosage: 1 teaspoon per 500 g of oils (approximately 3% by weight of the water in the recipe). Add to the infusion solution after cooling.

When to use: Summer production (high temperature = slower solidification), moulds with intricate design (earlier removal preserves details), mass production (faster mould turnaround).

Milk additives: sugars and proteins

Goat milk, almond milk, oat milk, coconut milk - see separate guide Goat milk soap.

The principle is the same for all lotions: sugars and proteins enrich the foam and condition the skin. The freezing technique applies to any milk containing lactose or other sugars.

Additives overview table

Frequently asked questions

Can I combine all additives in one recipe? Technically yes, but each additive will change the characteristics - temperature (honey), consistency (clays, bentonite), foaming (silk). Start with one ingredient, then combine after testing.

Do additives affect saponification or NaOH calculation? No. The calculator only calculates oils - additives are not reflected in the NaOH calculation. You add them on the trace, after saponification.

When exactly should additives be added — at light, medium or heavy trace? Light trace (liquid emulsion) - for powders (clays, inks). Mediu trace (thicker) - for liquids (panthenol, silk protein). Leaching solution - for sodium lactate and silk fibres. See table above.

Do additives accelerate gel phase like honey? Definitely honey. Clays (especially bentonite) also, but less. Silk and panthenol no. Vitamin E and ROE no.

Can I buy ingredients from the grocery store? Honey yes - food grade and cosmetic grade are identical. The others (clays, panthenol, ROE) are specifically cosmetic - not available for the food industry.

How many additives is too many? More than 3 ingredients in one recipe is complicated - each changes the behavior of the production. I recommend max 2 ingredients for beginners.

See also:

• Essential Oils in Soap - fragrances and therapeutic ingredients
• Natural colorants - herbs and plant extracts as ingredients
• Goat milk soap - detailed guide to dairy ingredients
• Activated charcoal soap - detailed guide to activated carbon