Gelling sugar shelf life affects jam thickening

Unlike regular table sugar, gelling sugar has a limited shelf life due to the presence of pectin, a plant-based active ingredient. According to the Verbraucherzentrale Bayern, the effectiveness of pectin can diminish over time.

Nutrition expert Katharina Holthausen notes that if the best-before date is significantly exceeded, jam may fail to thicken properly. However, using expired gelling sugar does not pose a health risk.

To test if the sugar is still effective, a ‘plate test’ can be used: place a spoonful of boiling jam on a plate and let it cool. If the mixture remains too liquid after cooling, the gelling agent may be ineffective. In such cases, adding lemon juice or additional gelling agents can help achieve the desired consistency.