Your jam is likely not setting because there isn't enough pectin to create the gel structure.
Jam sets when the natural or added pectin in the fruit combines with sugar and acid during cooking, forming a gel structure. If this crucial element, pectin, is missing or insufficient, your jam will remain runny.
The Pectin Problem
One of the primary reasons jam fails to set is a lack of sufficient pectin. Based on the provided information, this can happen for a couple of key reasons:
- Not Enough Natural Pectin: Some fruits naturally contain lower levels of pectin compared to others (like apples or citrus peels). If you use a low-pectin fruit and don't supplement it, the jam may not set.
- Using Overripe Fruit: The ripeness of the fruit significantly impacts its pectin content. As the reference notes, if the fruit is overripe, its pectin levels are lower. Using very ripe fruit can therefore contribute to a runny jam.
If there isn't enough pectin in the fruit itself and you don't add extra pectin, the result is runny jelly or jam.
The Solution: Add Pectin
Fortunately, you can easily remedy a pectin deficiency by adding commercial pectin.
- Added Pectin is Available: Added pectin comes in different forms. You can find powdered pectin and liquid pectin at grocery stores and online. Using a recipe that calls for added pectin, or adding it to a low-pectin fruit jam, helps ensure a proper set.
- Choose the Right Type: Follow recipe instructions for the specific type of pectin (powdered or liquid) you are using, as they are added at different stages and may require different amounts of sugar.
While pectin is often the main culprit, ensuring you have the correct balance of sugar and acid, and boiling the jam for the right amount of time at the correct temperature, are also important factors for a successful set.
