I personally feel uncomfortable to overestimate the amount of heat from the lye (hence, risk to end up with solid chunks of oil still swimming around in a batter that is already fully into saponification). I wouldn't recommend it to beginners, but won't deter those who find that it works for them.
I’m guessing that you have never used the Heat Transfer Method. Julie at Ophelia’s Soapery uses it quite often…here is a current link:
You will note that she has all her oils, soft and hard, in her container before she adds in her freshly made lye. She stirs for about five minutes then uses her stick blender to break up some of the remaining butters, stirs more until fully melted, and then stick blends until it is emulsified. Note how fluid her batter is…no solid chunks of oil swimming in ‘soap’. Then she adds in her FO, stick blends some more…the batter is still very fluid as she separates for colors. She whisks her colorants her, then goes back and stick blends and you will note that she has finally reached a light trace. She then drops both colors into her main pot and pours…batter is still fluid. Her batter is about a medium trace when drops the excess batter on top, but is still able to get a fluid swirl on top.
When she first started using the HTM, she just poured the fresh lye over her hard oils, melted them, then added her soft oils. This was the same technique that I learned from Jen at Be Scented. While I mainly Master Batch my Oils and Lye, there have been many occasions when I’ll make a soap from ‘scratch’ or run out of Lye Solution and use HTM.
Technically the ‘saponification’ process starts the minute you pour your lye solution into your oils…the lye starts to immediately bind with the oils. I really didn’t pay much attention to it until I started making my Lye Solution with 100% Goat Milk and could see the Lye binding with the fats in the milk.
This is not an article that I would recommend to beginning soap makers and there are a few things that I don’t agree with.
First is the temperature of her Lye Solution…it’s too low.
@DeeAnna can give you the exact science of why your Lye Solution shouldn’t go below about 70F.
Second, I soap at cooler temps…around 80F to 90F and I Master Batch. But even during the summer when my MB oils are like pancake batter, I still remelt them to about 100F-110F. It’s okay to have oils that are slightly cloudy, but you don’t want them thick and slushy, especially if you are using hard oils heavy with stearic acid…unless you like having Stearic spots in your soap. The only time I don’t remelt my oils is if I am using freshly made lye (200F-220F).
There is no ‘sometimes’ about false trace occurring…it will occur. And it’s not going to go away as easily as described…it’s takes more than just a bit of movement with your spatula to generate the heat needed to melt the oils. And notice she is using a stick blender in her photo, not a spatula. I’ve made soap with a spatula…took a soaping class. Mind you, our oils and Lye Solution was about 100F and it took a lot of ‘movement’ to get it to trace.