I had never heard about it. I knew that sodium citrate or sodium gluconate are used as chelators. Have you (o has someone else) found that vinegar reduces DOS in their soaps?The vinegar reacts with NaOH (lye) to become Sodium Acetate which is what hardens the soap and it apparently can also act as a chelator although I do not use it as the chelator in my soap.
That or the formula itself. But I'll bet it could be the dual lye.I will say I have been using distilled vinegar in the soap for a few years now from 50-100%. I use low CO and low superfat dual lye in my soaps which are either a tallow/lard based or high palm-based soap depending on vegan or non-vegan. My soaps lather well and I find the feel very creamy and lather nice and so did my very large customer base. In fact, many asked what I changed when I did change to my current formulas. As several told me, my soaps were always great but they went to fantastic. I never noticed any brittleness in my soaps even at 100% vinegar. I wonder if the dual lye makes a difference.