I went on line and entered "does BS or BP make softer cookies?" The answer was rather lengthy and I would have copied it and sent it to you if I knew how to do this. You can put in the same thing I did and read it for yourself. It did say that wether a cookie rises or not depends on the leaving agent, type of fats and sugar Also, things that are added like chocolate chips, etc. Wish I could have been more help. Good Luck. Lucy