F A Q
1. I have a question about making soap...
SoapCalc can only provide a limited perspective on your question. The many thousands of soapmakers available to you on soapmaking message boards and forums will ensure a more thorough answer.
You can pose the question to one of the first 6 Yahoo message groups listed here: These groups are free to join, the members are very helpful to newcommers and you can get many answers from the thousands of soap makers in these groups. It would be a good idea to mention what process you are using (CP, CPOP, HP, etc.). Also, if it's not a trade secret, your recipe. Click on 'Messages' on the left then you can search the archived messages for just about any topic on soapmaking - e.g. colorants, EOs, FOs, trace, seizing, orange spots, ash on top, temperature, lye concentration or water amounts, various specific oils used in soapmaking.
Go to Top
2. Can I use SoapCalc for making goats milk soap?
Yes, just put the milk (or milk/water solution) where you would put the water in SoapCalc. If you are not familiar with making soap with milk SoapCalc strongly suggests reading about it here: Making Milk based Soap at About.com (or getting a good book about it). When making soap with milk products as the liquid, some procedures are different from making soap with water as the liquid. Also check out the links at the bottom left of the above referenced web page.
Go to Top
3. What do the "'Individual" and "Combined"columns on the left mean?
The "One" column displays the soap qualities and fatty acid
percentages of the individual oil/fat selected in the center column. Notice that as you click on each oil, the numbers in the "All" column change to represent the qualities for that oil. The numbers in the "Individual" column will always display the qualities of the oil currently selected in the oil list, even after clicking "Calculate Recipe".
The "Combined" qualities display the soap qualities and fatty acid
percentages of all the oils listed in your recipe (the right column). These are
displayed after you click "Calculate Recipe". If you change an oil in your recipe or change a percent, "Calculate Recipe" must be clicked again to update the numbers in the "Combined" column.
Go to Top
4. What are the best values for Hardness, Cleansing, Condition, Bubbly and Creamy?
When you place your mouse over the soap quality for a moment (Hardness, Cleansing, Condition, etc.), a little box will show a suggested range of values. The suggested range of values is also displayed with the graph on the View Recipe page. These are guidelines; it's OK to go above or below these values a little. For more information please see the Soap Qualities page.
Go to Top
5. Can I use values (Hardness, Cleansing,etc.) outside of the guidelines?
The suggested values for soap qualities are only guidelines. SoapCalc can't say what will happen when you go outside these guidelines - the possibilities are endless.
Most soap makers experiment using small 1 pound batches to see what will happen. You will need to get your own experience in this.
Two examples that successfully go way outside the guidelines: 100% lard soap, and 100% olive oil soap. However in both cases there are special techniques required. The 100% lard soap traces quickly and can easily volcano out of the pot if the fat is too hot. 100% olive takes much longer to trace and much longer to cure.
Go to Top
6. What is the right "Water as % of Oils" for any given soap recipe?
The water in your recipe is required to separate the oils and fats into fatty acids and glycerine. This process, involving both the water and the lye is called hydrolysis and makes the fatty acids available to react with the lye and make soap. Most, but not all, of the water evaporates during the soap making process. More water is required for making soap at higher temperatures than at lower temperatures.
The calculator provides the percentage of lye in the water and lye solution. It also presents
this value as the 'Water:Lye' ratio. There is no "right or ideal" number to choose for
water as a percentage of the total amount of oils. However, when the lye is greater than 40% of the water and
lye solution, the hydrolysis process may not be complete and your soap may end up with some lye in it.
The calculator has a default value of 38%. It's a safe
starting point and will make a decent bar of soap for both CP and HP. You can experiment from
Caution: Lye solutions with higher concentrations
of lye will speed up the chemical process. Your oil and lye solution mixture could easily
bubble out of the pot and spill over your stove or table (or you). This happens quickly.
It is commonly called the volcano effect. Beginners should start with the default 38% "Water as % of Oils".
Tip: Keep a long spatula handy. If a volcano starts, immediately run the spatula rapidly back and forth edgewise through the mixture. I have found this technique useful for keeping a volcano within the pot. Of course, it is good practice to use a pot large enough so that the mixture is comfortably contained in less than ½ the pot.
Go to Top
7. What is superfat or discount?
If you use all the lye necessary to exactly saponify all of the fatty acids in the
oils, the soap would have no excess lye or excess oil (next to impossible without a chemistry lab).
It would have a zero discount and there would be no superfat. If you discounted the lye,
let's say by 5%, 5% of the soap would contain oils that have not chemically reacted with the lye.
i.e. all the lye was used up in reacting with 95% of the oils. The soap would have a 5% superfat. These
unspecified oils are good for conditioning the skin. A soap with no discount or superfat will clean
better. However, other than conditioning the skin, there are other important reasons to discount the
lye (or superfat the soap). Please see the next question.
Go to Top
8. Why is a minimum 5% discount recommended?
The SAP values used to calculate the amount of lye - in this calculator and in others - is
an average. If you purchase oils/fats that have been assayed by a chemical lab, you will know
the exact SAP value of the oils/fats. (Your wallet will be a little thinner too). If you weigh these oils
and the lye on very precise laboratory scales, you can confidently make a true zero discount soap.
One of my references gives the Potassium Hydroxide (chemical symbol KOH) SAP value for coconut oil as 250-264.
The SAP for other oils is specified similarly as a range of values. Why? There are many variables that
contribute to the chemical qualities of a carrier oil. Here are a few to give you the general idea:
- Species of the botanical used to make the oil.
- Geographical location of the source botanical. i.e. variable climate.
- Varying types of processes used to create the oil.
- Seasonal differences in when the botanical was harvested.
- Maturity of the botanical when it was harvested.
The minimum 5% discount/superfat is recommended to allow for these variances so you do
not end up with soap that contains unused lye.
Go to Top
9. What is milk fat (bovine)?
It is not butter, half and half, or heavy cream. It is the pure cream contained in those products.
It is made by spinning natural whole milk
(straight from the cow or other bovine animal) in a centrifuge like device.
Some soapers have access to natural whole milk and can buy a cream separator or can buy milk fat from a local dairy.
Heavy cream has a fat (cream) content of between 36% and 40%.
Check these links for more info:
What is Heavy Cream?
Go to Top
10. What shortening do I use?
The "Walmart GV Shortening, beef tallow, palm" in SoapCalc is described here.
It is primarily made with palm oil and beef tallow and comes in a 42 oz paper can.
"Walmart GV All-Vegetable Shortening" is the same as an older version of Crisco. It is primarily made using partially hydrogenated soybean and cottonseed oils and comes in a 48 oz paper can. In SoapCalc use "Crisco, old". The product information is here.
The new Crisco is made from soybean oil, partially hydrogenated palm and soybean oils, and fully hydrogenated palm oil. use "Crisco, new w/palm" in SoapCalc.
For almost any brand of all vegetable shortening (no beef tallow):
- If made from partially hydrogenated soy and cottonseed oils use "Crisco, old".
- If made from soybean oil, partially hydrogenated palm and soybean oils, and fully hydrogenated palm oil use "Crisco, new w/palm".
All of these shortenings contain a small amounts of Vegetable Mono- And Diglycerides, BHA or TBHT, Propyl Gallate And Citric Acid as antioxidants. Walmart GV Shortening (the one with beef tallow) contains Dimethylpolysiloxane, an anti-foaming Agent. Anti-foaming agents can reduce the amout of bubbly in soap; however Soapcalc has used this product an found it to make great soap (at about 50% of recipe) without any noticable loss of bubbles.
Go to Top