what do you mean by relating discount/superfat...
is there a link between discounting and super fatting?
What I mean is, if eg. I SF a recipe by 7%, and use a 2:1 [water:lye] ratio can the one (discount) affect the other (SF)?
Isn't lye discount used only to achieve faster the mature state of a soap or discount does affect SF of a recipe? or I have confused things in my mind... I am new and eager and read and study and confusions do happen
I’m sorry. I knew I would end up confusing you somehow. I should have just written superfat because I think more people use this term. Lye discount and superfat can be used interchangeably when discussing using more oil than is needed for 100% saponification.
A lye discount only affects the superfat. It will not produce a faster cure time.
I am using calculations for 100% olive oil to show examples. This actually isn’t a good example because you would want to use a water discount for Castile so it won’t take so long to trace.
Lye discount just means using less lye than needed for 100% saponification. You would use only 95% of lye needed for full saponification if you wanted a 5% superfat. A 900 g batch would require 121.9 g for 100% saponification. You would use 115.8 g lye for 900 g batch to have 5% superfat.
Superfat is adding more oils. A 900 g batch would require 121.9 g for 100% saponification. You would add an extra 47 g of oil to get 5% superfat so the batch weight would end up being 947 g.
The water:lye ratio doesn’t have anything to do with superfatting. This ratio is the amount of water to the amount of lye. It tells you the lye concentration you are working with for a batch. Generally, new soapers start with what is considered a full water amount which is approximately 3:1 ratio – 3 parts water and 1 part lye. This would give you approximately 25% lye concentration. I say approximately because I’m rounding the numbers off. (BTW, I use SoapCalc for a
lye calculator.)
As you become more experienced with soapmaking, you will want to use a water discount for well behaved recipes and fragrance oils. A water discount will increase the lye concentration so there is less water to evaporate from the soap. However, less water also means the batch will move a little faster which is why you want to know how fragrance oils and additives will affect your recipe. Generally, I use 33% lye concentration (2:1 water:lye ratio) for recipes I know I won’t have problems with and I’m using fragrance oils which won’t accelerate. This means the batch won’t zip through trace and seize up. I would use 25% lye concentration (full water amount) for a new fragrance oil or for one which I know will accelerate.
I would use 40% lye concentration (1.5:1 water:lye ratio) for 100% olive oil so it wouldn’t take
forever to reach trace.
Although, less water to evaporate makes it sound like it will shorten curing time; it really doesn’t since there is more going on during curing than just the evaporation. The soap is still going through changes over several weeks. I will say a week possibly might be taken off the cure time depending on the recipe. However, this is just my opinion and other people may disagree with a 3 week cure time. But I have a very basic recipe that is all right at 3 weeks and I would be willing to give it away. However, I know it will continue to become a little more mild and the lather more bubbly after 4-5 weeks curing. I have other recipes which don’t become the best they will be for 6 to 8 weeks. I think Castile soap isn’t good to go until after an 18 month cure but that’s just me. I know other people have different cure times – anywhere from 4 weeks to 6 months. It’s personal preference.
I’m like coffeetime as I also have many recipes. I have a couple that I consider cured at 4 weeks. Most of my recipes I think are the best after 6 weeks. I have one which really needs 5 months before it’s at its best and another which needs at least 9 months since it has a high percentage of olive oil.
I know I sound boringly repetitive but you need to experiment to find out what you like and how long it takes for different recipes to cure.
eta: You might find these articles helpful.
http://cavemanchemistry.com/LyeDiscount-Dunn.pdf
http://cavemanchemistry.com/WaterDiscount-Dunn.pdf
http://rivercitysoaps.com/dwcp/dwcp.pdf