Hello Everyone! I am new to soap making and I would like to know more about a recipe that I've seen done, but I don't understand why is was done that way.
The recipe is the following:
Lye / Water were mixed before and cooled. The Lye was 25L and the water is 19L
8L of oils
- Olive pomace oil 33.33%
- Coconut oil 33.33%
- Palm oil 33.33%
- Lye / Water 1500ml
What is the benefit of having more or less Lye / Water in soap making? Also why 1500ml of Lye / Water? What is super fat and is it required? If I need to change the recipe to 1L instead of 8L what would be the Lye / Water amount?
Your help would be much appropriated.
Thanks,
Sam
Sam, just to add to Irish Lass's information on the recipe being the "holy trinity" recipe (1/3 of each olive, palm and coconut) ... the litre/liter measurements probably dates prior to accurate scales being commonly/cheaply available.
" ... why 1500ml of Lye / Water?"
The recipe looks like what we now call a "masterbatch" solution of lye is being made, and a portion of that masterbatch is used to make the individual (very large) recipe.
This part of the recipe is the masterbatch: "
Lye / Water were mixed before and cooled. The Lye was 25L and the water is 19L"
This part of the recipe is the portion to be used for the 8L of oils in the recipe:
"Lye / Water 1500ml"
When masterbatching lye solutions by weight, a minimum amount of 1 part water to 1 part hydroxide is required. This masterbatch recipe is given in volume, so the numbers look wrong to someone used to measuring accurately (by weight). This happens because the same volume of water and sodium hydroxide weight different amounts (the water is heavier).
The phrase "Lye / Water" means lye solution. Lye is commonly used to describe both the dry hydroxide and the lye solution, so a clear distinction for use in a recipe is always a good idea - back then "Lye / Water" would be as clear to the original intended reader of that recipe as "lye solution" is to us today
"If I need to change the recipe to 1L instead of 8L what would be the Lye / Water amount?"
You can't resize a volumetric recipe down with any accuracy - these sorts of volumetric recipes tend only to function well in large volumes - going smaller (even if the recipe is a good one to begin with) requires increasing the accuracy of measurement. Precise weights gives far greater accuracy when measuring ingredients, which is why we convert the recipe to precise weights.
So, the recipe you have (to plug into a calculator by percentages) is:
33.3% palm oil
33.3% coconut oil 76C
33.4% olive oil
38% lye concentration (roughly) - I would a little more water, at 30% to 33% lye concentration for your first batch
5% superfat (roughly - don't got below about 3% for safety, or above about 7-8% to avoid rancidity in your soap later on <- this is general advice only, some other, quite valid, recipes vary wildly from this, but this rule is a good one to start with).
... Truth be told, none of us could make the soap without those calculators. ...
Saponification tables are still available for fats. These tables pre-date modern day computers. Basic maths is required to calculate a soap recipe, but it is not as difficult as it may first appear.
For example, olive oil in most calculators is set to about 0.135 for the NaSAP value (the amount of sodium hydroxide required for each 1 part of the oil).
What this means is that for every 1000 grams of olive oil, 135 grams of sodium hydroxide is needed to make a zero superfat soap. Or, another way to think about it ... whatever the weight of the oil is ... multiply that by 0.135 and you have the weight of sodium hydroxide you need to saponify that particular oil completely.
For safety, a minimum "superfat" of about 3% is used to make a homemade soap, with 5% being the common recommendation (as always, there are variations on this). Once you have decided on your lye discount (which is how a lot of the calculators give you your "superfat"), reduce the sodium hydroxide value accordingly. So if you want a "superfat" of 5%, take your total sodium hydroxide weight and multiply it by 0.95 (which is 100%, less 5%, in decimal form). That gives you your final sodium hydroxide weight (eg. 135grams x 0.95 = 128grams for our olive oil soap example)
By understanding that a minimum of 1 part water to 1 part hydroxide is needed, you also know that you will need AT LEAST 128 grams of water for this. To get a 2:1 water:lye ratio (which is very close to a 33% lye concentration), you will need twice the amount of water as hydroxide, so that would be 256grams of water.
So ... for a one fat (oil) recipe, that's how it's done.
For a multi-oil recipe, you have to reproduce the lye calculation for every oil (each oil has a different saponification value - that's the part that you need to know).
But at the end, all you do is add up the total weight of the hydroxides and do the same as for your single oil soap ... apply your lye discount (in our example we multiply by 0.95 to get 5% lye discount) and work out how much water you need (multiply the hydroxide amount by two is a simple way to remember it).
For Sam's trinity soap, to make a 500 gram batch, the math would be:
Palm oil, 500grams x 1/3 = 166.7 grams
Coconut oil, 500grams x 1/3 = 166.7 grams
Olive Oil, 500grams x 1/3 = 166.6 grams
Sodium hydroxide
Palm oil, 166.7 grams x 0.142 = 23.67 grams
Coconut oil, 166.7 grams x 0.183 = 30.51 grams
Olive oil, 166.6 grams x 0.135 =22.49 grams
Total sodium hydroxide to make a zero percent superfat = 23.67 + 30.51 + 22.49 => 76.67 grams
Lye discount ("superfat") of 5% = 76.67 grams x 0.95 = 72.8 grams NaOH
Water = 2 x NaOH = 2 x 72.8 grams = 145.6 grams Water
So the 5% superfat, 2:1 lye ratio, trinity soap recipe, for 500 grams of oils, becomes:
166.7 grams Coconut Oil
166.6 grams Olive Oil
166.7 grams Palm Oil
72.8 grams Sodium Hydroxide
145.6 grams Water
geniash ... you can do this