There are dye's that can be used, the mixers are jacketed and freon use, to run threw the jacket to cool the dough to a constant temperature. Now glychol is used and is dyed to alert to an imediate leak which I have never seen by the way or we would have blue dough. So if you want blue oil email me N8ygn@aol.com Have you ever baked bread at 2000 lbs. ever 15 minutes. I have.