Hard predicts the hardness of the soap. A normal soap bar falls between 29 and 54 with the higher number indicating a harder soap bar and the lower number indicating a softer bar. Butters and waxes contribute to harder bars as well as coconut oil, palm kernel flakes, lard and tallow.

Cleanse predicts how well the soap will clean and pick up oil from the skin. A normal soap bar falls between 12 and 22. The higher number means the soap will be more cleansing and thus harsher on the skin whereas the lower number means it will not cleanse as well but will be gentler on the skin. Ultra cleansing oils include babassu oil, coconut oil, murumuru butter, palm kernel flakes and tucuma seed butter.

Condition predicts how well the soap will condition skin. A normal soap bar falls between 44 and 69. The higher number indicates a more conditioning bar and the lower number indicates a less conditioning bar. Ultra conditioning oils include sweet almond oil, apricot kernel oil, argan oil, avocado oil, camelina seed oil, castor oil, evening primrose oil, grapeseed oil, hazelnut oil, hemp oil, meadowfoam oil, olive oil, rosehip oil, safflower oil, soybean oil, sunflower oil, walnut oil and wheat germ oil.

Bubbly predicts the lather. A normal soap bar falls between 14 and 46 with the higher number indicating bigger bubbles and the lower numbers indicating smaller creamy bubbles. Ultra bubbly oils include babassu oil, castor oil, coconut oil, murumuru butter, palm kernel flakes and tucuma seed butter.

Creamy also predicts the lather. A normal soap bar falls between 16 and 48 with the higher number meaning a creamy lather and a lower number meaning more bubbles. Ingredients that contribute to a creamy lather include beeswax, candelila wax, castor oil, cocoa butter, kokum butter, mango seed butter, palm oil, sal butter.

Iodine also predicts the hardness of soap. A normal soap bar falls between 41 and 70. A lower number means a harder bar and a higher number means a softer bar. Oils that are low in iodine include babassu oil, beeswax, cocoa butter, coconut oil, cupuacu butter, kokum butter, palm kernel flakes, sal butter and tucuma seed butter.

INS is an overall gauge. The ideal INS is 160 according to the soap calculator. The recommended range is from 136 to 165. Ingredients with high INS values are babassu oil, cooconut oil, murumuru butter, palm kernel flakes and tucuma butter.

Keep in mind that these ranges are useful when first formulating soap recipes, but they are by no means an absolute must. There are other factors that contribute to a soap's overall performance which include the super fat, water discount, additives, etc. We hope this information helps with your next new soap recipe!

Note that Pine Tar only affects the lye calculation, but is not factored into the properties calculations. Pine Tar when included is typically 3-10% of total oil weight.

Beeswax will make a soap bar last longer in the shower. It should be limited to no more than 2% of total oil weight.

Other additives which do not affect calculations:

• essential oil such as tea tree oil, lavender, lemongrass, etc. (up to 30g per 1000g oil)
• activated charcoal (up to 1 TBSP per 1000g oil)
• bentonite clay (up to 1 TBSP per 1000g oil)
• salt (1 TBSP per 1000g oil); too much can make the bar crumbly

DRY SOAP

PROBLEM: Soap crumbles when you cut into it.

SOLUTION: Soap is lye heavy.

ACTION: Too much lye or too little oil. Check your measurements.

SOFT SOAP

PROBLEM: Soft soap is malleable and gelatinous.

SOLUTION: Soap is lye deficient.

ACTION: Too little lye or too much oil. Check your measurements.