The Iodine Number or Iodine Value is numeric indicator that is determined by a chemical test that measures how many centigrams of iodine can be dissolved per gram of oil. It measures the saturation of the oil/fat and depicts the amount of unsaturated fatty acids present. Saturated fats often have low iodine values and will create harder soaps. Unsaturated fats have high iodine values and will create softer soaps. High iodine soaps might be more prone to oxidation and DOS, but this isn’t an absolute. An informed recipe will have a blend of saturated and unsaturated fats for a balanced soap with desirable qualities.
Interested in learning about the science of soap making? Be sure to check out our article about the important of learning fatty acids in soap making here!
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