Soak Time at Peak Temperature: The Hold Duration That Minimises the Combined Cost of Fuel and Underfired Rejects

This paper addresses kiln loads in which ware near the cooler zones is underfired when the firing ends as soon as the hottest cone falls. It presents a soak-duration rule that prices fuel for the hold against the value of rejects avoided, derived entirely from stated assumptions and a computation whose code and full output accompany the paper. The sweep covers soak duration at peak temperature from 0 to 4 hours. The headline outcome is: best x 3; best total usd 35; total no soak usd 270; reject at best 0.024; reject no soak 0.3; total at 4h usd 36.5. These figures identify a specific operating point or bound that a workshop can apply directly, and they also show how quickly performance deteriorates away from it. No kiln was built, no ware was fired, and nothing was measured for this study. SIMULATED, NOT MEASURED.