A mystery - please help
I am making Hamelman's sourdough seed bread according to the instructions on this website for almost a year - a wonderful bread. I am using a very successful starter that I started myself. Recently (about a month) the bread has a taste of soap ??? You take a bite, and first it is unnoticed. But after few seconds you cannot be mistaken - a sharp taste of soap. I discarded several loafs, and started from the beginning trying to improve anything I could: bought new flour (King Arthur), new flax seed, new sesame and sunflower seeds. I made sure no soap remnants in the tools I use - everything was washed and dried with a lot of water, including the kneading area. And today - 2 new loafs with the same taste.
Does anybody have an idea? is it any chemical reaction that creating that weird and bad taste?