Turmeric (Curcuma longa) is a rhizomatous plant native to South Asia, cultivated for millennia as a spice, dye, and ingredient in traditional wellness practices across India, Southeast Asia, and parts of the Middle East. The dried root is ground into a vivid golden powder that has become one of the most recognizable natural colourants used in botanical skincare. At Eternal Sunday, we use it in our Turmeric Revitalizing Unscented Soap, where it gives the bar its characteristic golden tone.
How we source it
We purchase turmeric powder from a bulk store, bringing our own container to avoid single-use packaging. Because a little goes a long way in soap formulation, a single purchase lasts through many batches. It's a small but deliberate choice, using a food-grade ingredient available in bulk means less plastic, less waste, and a direct connection to an ingredient that has been traded and used across cultures for centuries.
How we use it
Turmeric is added as a powder directly to the oils and butters before the lye water is introduced. This is the most effective technique for natural colourants in cold-process soap: dispersed through the fat phase first, the pigment integrates evenly before saponification begins, producing a consistent colour throughout the bar rather than streaks or uneven patches.
The timing matters. If turmeric were added after the lye water, the batter would already be thickening and the pigment would have less time and mobility to distribute. Added to the oils first, blended smooth, then combined with everything else, it becomes part of the formula from the beginning.
What happens to the colour during cure
Fresh turmeric soap has a vivid, almost neon-gold colour immediately after pouring. Over the four to six week cure period, the colour deepens and settles into the warm amber-gold you see in the finished bar. In combination with the carrot juice we use as the water phase, the two natural colourants reinforce each other, both beta-carotene and curcumin contributing to the same golden register from different directions.
The colour on the surface of a cured bar will be slightly different from the interior. This is normal and characteristic of naturally coloured soap. It reflects how the pigments interact with air and light over time, not a formulation inconsistency.
A note on claims
Turmeric has a long history of use in traditional practices and is widely studied for its properties as a food ingredient. In a rinse-off product like soap, contact time with skin is brief and the active compounds are present in small amounts. We use turmeric in this soap because it produces a beautiful natural colour and is a meaningful part of the formula's botanical character, not to make any claims about its effects on skin.
In our products
Turmeric currently appears in our Turmeric Carrot Revitalizing Unscented Soap, where it works alongside fresh Ontario carrot juice to give the bar its colour. Together they produce a golden, conditioning bar with a character that comes entirely from plants.
