The dry roasting process employs either the batch or continuous method. In the batch method, peanuts are heated in large quantities in a revolving oven at about 800 °F (430 °C). Next, the peanuts in each batch are uniformly held and roasted in the oven at 320 °F (160 °C) for about 40 to 60 minutes. This method is good to use when the peanuts differ in moisture content. In the continuous method, a hot air roaster is employed. The peanuts pass through the roaster whilst being rocked to permit even roasting. A photometer indicates the completion of dry roasting. This method is favored by large manufacturers since it can lower the rate of spoilage and requires less labor.