@Julia M. Usher posted:@Sandy_S, Thanks for the photos and for posting under this very related thread. You have to be SUPER careful about leaving cookies IN the dehydrator, especially that long. All sorts of stuff can happen if they overheat. On smaller cookies, I've had the icing puff up and crack; I've also had ripples blown into icing that evidently was too thin; I've also had the icing speckle and mottle even after coming out of the dehydrator. So now, I dry on a tray IN FRONT of my open dehydrator, about 12 inches away from the door, so it's acting more like a fan. I typically dry cookies this way for no longer than one hour, but I also start with icing as thick as it can be to smoothly flood. My icing always sets more uniformly if on the thicker side. In your case, it looks like your cookies got too hot and some of the fat from the cookie bled into the icing.
Thanks so much for the very helpful info, Julia. If I need to use the dehydrator again I will perhaps put the cookies on the top shelf and maybe even leave the lid a bit askew so the cookies will dry more slowly and less warm. So from what I’m reading, am I correct to believe that they shouldn’t have to be in there for more than an hour?
Thanks again for your reply. I know how busy you are so I truly appreciate you.