Thank you for your reply, Norcalbaker. I use the technique you mention for my chocolate crinkle and molasses ginger cookies when I'm looking for a cracked, crinkled effect. Making ripples in a cookie is a little bit different. The ripples look like waves that start at the outer edge of the cookie and move towards the center. Banging the cookie sheet against the oven rack several times before cookies are done creates a rippled effect in the cookie. I'm hoping to find another method of making ripples in cookies that don't involve banging the pan.
No, the science behind it is essentially the same. All that is happening when banging the sheet on the countertop is breaking the gluten structure before it sets. Then allowing it to bake and set.
The sugar coating on crinkle cookies snickerdoodles is exactly the same thing. It pulls the moisture from the cookie, and dries it out the crust, and breaks the gluten structure early before it sets. The cookie continues to bake.
Your only other alternative is to bang the cookie sheet. There’s no other way to disrupt the baking process. Baking is a chemical reaction of all the ingredients to temperature and time. so you either interrupt the baking process physically by banging the cookie sheet, or you interrupted chemically, which is to use sugar.