In this paper is shown optimal auto-tuning procedure for tuning of temperature controller in a process of fruit and vegetables dehydration. The dehydrating process is the first order model with transport delay. For temperature control. a proportional-integral-derivative controller is used. https://www.alarecre.com/Looney-Tunes-Marvin-the-Martian-Big-Head-Galaxy-S23-Waterproof-Case-p116784/