Hi Ladies, Have you used soapcalc?
www.soapcalc.com It's a great resource to all saponifiers and will help to prevent you from making lye heavy batches that will burn you or batches that are oil heavy that will go rancid. It is a great resource for those of us who want to make our own recipes since all oils have a different saponification value and are not interchangeable. The only thing I would like to note about soapcalc, is when it gives you the properties of the finished bar of soap, it does not take into the account the unique property of OLIVE OIL to harden. It lists the bar as too soft, but remember that olive oil will produce a very hard bar, if allowed to cure long enough, so remember to take that into account if you are using a large percentage of olive oil.
As for using your own pressed oil: the only single oil soap I would recommend is soap made from olive oil. Other than that, it is best to have a mix of oils since different oils offer different properties to the soap. For example, coconut oil makes your bar hard and gives lots of bubbly lather, but it is harsh on the skin. Castor oil, is good on the skin and gives lots of thick lather but it does not have very good cleansing properties.... so mixing several oils with different properties is the key to a good bar of soap.
My final note on soap is to say that unless you are a vegetarian and avoid animal products alltogether, there is not reason to avoid tallow in soaps. Tallow makes a lovely soap, my best soaps are made with 35% tallow and the rest vegetable oil. AND tallow is often FREE because you can just get the fat for free from the butcher and render it yourself (I do it in a turkey fryer in the back yard because rendering fat STINKS)
If you have any questions about soapmaking please feel free to ask, I have made hundreds of pounds of soap and I've made TONS of mistakes and have ruined a lot of soap so I actually know a lot about what NOT to do!
