The Amount of Lye Required to Make Soap

Can you make soap without lye?
No, you can't.

Speaking simply, soapmaking is a chemical process. Lye converts fat to soap. Properly made soap no longer contains lye. It's just soap, glycerin, a bit of excess fat, fragrance and any additive you put into the soap mixture.

This chart is for experienced soap-makers only.

This chart is really easy to use!
Don't confuse the numbers in this chart with normal saponification values that require complicated equations to calculate the amount of lye to saponify fats.

In this chart, the math has been done for you.
All you have to do is multiply the number of ounces (or grams) fat you would like to use, times the number in the chart. The answer is the number of ounces (or grams) lye (sodium hydroxide) required to saponify that much fat.

Nothing is "exact" in science. These numbers are based on the "average saponification value" of particular oils. For instance, the saponification value of macadamia ranges from .193 to .198, depending on the source of the oil and how it's refined. These values also don't allow for the fact that technical grade lye is 97% pure.

Use these exact numbers and your soap will contain a bit of excess fat, yet they will never contain too much lye. It's good to calculate the lye as closely as possible. If you want soap even more superfatted, add measured amounts of excess fat.

Inventing soap recipes is quite an art. Some fats tolerate more excess fat in soap than others. The more saturated fats tolerate more superfatting and result in soap that traces and hardens more quickly.

I like to use saturated fats for at least 1/4 of the total fat in a recipe. Saturated fats include: coconut oil, babassu oil, palm kernel oil, beef tallow, palm oil and lard.

How to use the chart.
It's really easy. Just multiply the number of ounces of whatever fat you would like to use, times the number in the chart. The answer is the number of ounces lye (sodium hydroxide) required to saponify that much fat.

For example:
I want to use 1 lb palm oil. I multiply 16 oz. weight
(for the 1 lb measurement) times .141 and get 2.256 for an answer. This is the amount of lye required, so I round off the number to 2.3 oz to weigh on my scale (which doesn't indicate that many decimal places).

Another example:
I only want to add 4 oz weight of palm oil to a recipe. Multiply 4 oz times the same number in the chart, .141 and the answer is .564. Round off to .6 and this is the amount in oz sodium hydroxide required for 4 oz palm oil. Easy enough?

Using Potassium hydroxide
instead of sodium hydroxide.
I received many questions about substituting the types of lye. I've made a few test batches of soap with potassium hydroxide and it definitely stays soft much longer, but eventually hardened the same as if sodium hydroxide was used. In case you want to know the amount of potassium hydroxide to use in a soap recipe, go ahead and calculate the amount of sodium hydroxide required. Multiply the number oz sodium hydroxide by 56 and divide the answer by 40 to equal the amount potassium hydroxide required (more potassium than sodium).

Be aware that potassium hydroxide reacts more violently when added to water than does sodium hydroxide. Allow plenty of room in the container for possible "boiling up."

The Numbers:

.136 almond oil, sweet almond oil, Prunus amygdalus oil

.135 apricot kernel oil, Prunus armeniaca oil

.136 arachis oil, peanut oil, earthnut oil, katchung oil, maize oil

.133 avocado oil, Persea americana oil

.175 babassu, Brazil nut oil

.069 bayberry or myrtle wax

.139 bear fat, bear tallow

.141 beef hoof oil, neat's foot oil

.140 beef tallow, beef fat, beef suet

.069 beeswax

.136 borage oil, Borago officinalis oil

.175 Brazil nut oil, babassu oil

.162 butterfat, cow

.167 butterfat, goat

.136 camellia oil, Camellia sinensis oil

.124 canola oil, rapeseed oil, colza oil, rape oil, ramic oil

.069 carnauba wax

.128 castor oil, ricinus oil

.138 chicken fat

.137 China wood oil, tung oil, nut oil

.135 Chinese bean oil, soybean oil

.137 cocoa butter, theobroma oil

.190 coconut oil, Cocos nucifera oil

.132 cod liver oil, banks oil, morrhua oil

.130 coffee-seed oil

.124 colza oil, canola oil, rape seed oil

.136 corn oil, maize oil

.138 cottonseed oil

.135 Chinese vegetable tallow

.139 deer tallow, venison fat

.136 earthnut oil, peanut oil

.135 emu oil, emu fat, ostrich oil, ostrich fat

.136 evening primrose oil, Oenothera biennis oil

.135 flax seed oil, linseed oil

.134 Florence oil, olive oil, lovvu oil, Glotrnvr oil, olium olivate, sweet oil

.133 gigely oil, sesame oil, teal oil

.139 goat tallow, goat fat

.136 goose fat

.123 to .135 grape seed oil, grapefruit seed oil, Vitis vinifera oil (varies widely)

.136 hazelnut oil, Corylus avellana oil

.1375 hemp oil, hemp seed oil

.136 herring oil, fish oil

.137 java cotton, Kapok oil

.069 jojoba oil, Simmondsia chinensis oil

.137 kapok, Java cotton oil

.128 Karite butter, shea butter

.136 Katchung oil, peanut oil earthnut oil, arachis oil, maize oil

.135 kukui oil, candle nut oil

.074 lanolin, sheep wool fat

.138 lard, pork tallow, pork fat

.136 linseed oil, flax seed oil

.134 loccu oil, olive oil, Florence oil, olium olivate, sweet oil

.139 macadamia nut oil, Macadamia integrifolia oil

.136 maize oil, corn oil

.136 margarine

.135 menhaden, fish oil. pogy oil, mossbunker oil

.140 mink oil

.123 mustard seed oil

.138 mutton tallow, sheep tallow

.069 myrtle wax, bayberry wax

.138 neem

.141 neat's foot oil, beef hoof oil

.135 niger-seed oil

.134 olium olivate, olive oil, loccu oil, Florence oil, sweet oil

.135 ostrich oil, ostrich fat, emu oil, emu fat

.141 palm oil

.156 palm-kernel oil, palm butter

.136 peanut oil, earthnut oil, katchung oil, arachis oil, maize oil, Arachis hypogaea oil

.136 perilla oil

.135 pistachio oil

.138 poppy-seed oil

.135 pumpkin seed oil, Cucurbita pepo oil

.128 rice bran oil

.124 ramic oil, canola oil, rape seed oil, colza oil

.128 ricinus oil, castor oil

.136 safflower oil

.135 sardine oil, Japan fish oil

.133 sesame seed oil, gigely oil, teel oil, til oil, teal oil, Sesamum indicum oil

.128 shea butter, African karite butter

.138 sheep fat, sheep tallow

.074 sheep wool fat, lanolin

.136 shortening, vegetable shortening, hydrogenated vegetable oil

.135 soybean oil, Chinese bean oil, Hellanthus annuus oil

.134 sunflower seed oil

.137 Theobroma oil, cocoa butter

.137 tung oil, soybean oil, China wood oil, nut oil

.138 venison fat, deer fat, deer or venison tallow

.136 walnut oil, Jugulans regia oil

.092 whale: sperm whale, body, blubber oil, train oil

.102 whale: sperm whale, head

.138 whale: baleen whale

.132 wheat germ oil, Triticum vulgare oil

.074 wool fat, lanolin

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