He never warms the jars, so why doesn’t my son’s marmalade go mouldy?
Our preserving pundits dive into the bittersweet dilemmas surrounding baking paper circles, wax seals and the judicious application of heat
TL;DR
- High sugar content in marmalade prevents mold by binding to water.
- Food-grade lids with wax seals are more effective than older sealing methods.
- Using clean, new lids is essential for a proper seal and preventing contamination.
- Reused lids should be free of dents and odors, and can be sanitized by simmering.
- Heating jars is recommended to eliminate mold and yeast, though some consider it optional for clean jars and high-sugar preserves.
- Overcooking marmalade results in a caramelized, barley sugar-like flavor.
- Marmalade is ready when light, white bubbles disappear and the surface becomes glossy with slower boiling.
- Jars should be filled nearly to the brim to minimize air exposure and prevent contamination.