A preserving pan is a large, wide, heavy-based pan designed for making jam, chutney, marmalade, and other preserves. The wide diameter maximises surface area for rapid evaporation, which is essential: jam sets properly only when water boils off quickly to reach the setting point around 105 °C before the fruit overcooks and flavour dulls. Traditional preserving pans are unlined copper, whose superb heat conductivity gives precise control, though stainless steel with a thick base is the modern practical choice; aluminium is avoided by some for acidic fruits. A long handle or two loop handles manage the heavy, bubbling load safely. The pan’s size matters: filling no more than half allows the vigorous boiling that makes good jam, which is why serious preservers invest in a proper pan rather than struggling with an undersized saucepan.