Rustic Plum Jam

Plums must be ripe but firm to avoid falling apart too soon and creating a grainy jam. Italian or Mont-Royal types preferred. If unavailable, use any firm, slightly tart plum variety. Skipping pitting risks bitter pit flavor; take time to remove stones. Raw sugar slows caramelization and adds mild molasses notes, but coconut sugar or palm sugar works well without sharp aftertaste. Lemon juice is acid that triggers pectin action—don’t omit or risk flat jam. Fresh ginger adds complexity, balancing sweet and tart but omit if avoiding spice. For a sweeter jam, add honey at end off heat. Always keep stirring just enough to prevent sticking or uneven cooking. Sterilization prevents spoilage but cold storage as backup. Freeze leftover jam in smaller containers to retain freshness but expect texture softening.

Don’t rely on a clock alone. The familiar change in boil noise — from sharp spatter to slow bubble pop— called the ‘rolling boil’— signals when jam thickens. Stir frequently but not constantly to keep pulp intact and prevent hot spots on pan bottom. Skim foam early; at later stages, fold it back to maintain volume and flavor. The plate test is key—drop jam on chilled plate and push with finger after a few seconds. If it wrinkles, you’re done; if it flows or spreads, cook longer. Jar prep crucial—clean jars crack if cold or seal fails. Heating filled jars by inversion or water bath extends shelf life significantly and kills residual molds. Watch for broken vacuum seals, store opened jams properly. Avoid jam crumble by not overheating. Temperature 104-105°C ideal but thermometer optional. Trust sensory signs. Jam thickness increases as it cools and sets. Quick cooling stops cooking to prevent darkening or burnt taste. Quick refrigeration if unsure. Use non-reactive pans: stainless steel or enamel avoids metallic flavors. Aluminum can cause discoloration.