I made a soap and separated out part of it. I added sodium lactate at about 3% of the weight of the oils in that part. And, I used a green colorant. So, the soap that came from this part of the mixture turned brown about a week later. The soaps that came from the other part of the mixture (with no sodium lactate and a camel colored colorant) didn't become brown. Not only did the soap turn brown but where it was touching another soap it turned the other soap brown too. Any ideas what happened?