In a saucepan, add in raspberries, white sugar and lemon juice, over high heat.
Stir with a wooden spoon, keeping the mixture moving to ensure it doesn’t burn.
Slowly it’ll break down and mix together, and come to a boil.
Keep the boil going, stirring slowly, for about 10-15 minutes.
By this point it should be thicker.
Turn off the stove, place the jam into clean glass jars and pop into the fridge.
Raspberry jam will keep refrigerated for a few weeks.
Pectin and Sugar Ratios
Commercial preserves rely on added powdered or liquid pectin to achieve a set, but this formulation depends on the natural pectin found inside raspberries combined with a high proportion of white sugar. Raspberries contain a moderate amount of pectin compared to tart apples or citrus fruits, which requires maintaining a vigorous boil for 10 to 15 minutes to evaporate excess water and concentrate the remaining natural starches. White sugar acts as a preservative and structural agent here; reducing the sugar quantity below the specified 220 grams will prevent the jam from thickening properly during the cooling phase. Measuring fruit and sugar by weight rather than volume ensures consistent results every single batch.
Acid Balance and Substitutions
Fresh lemon juice introduces necessary acidity that breaks down the fruit cellular walls and helps extract the natural pectin while balancing the intense sweetness of the sugar. Bottled lemon juice works identically to fresh-squeezed juice because the citric acid concentration remains reliably consistent. Lime juice makes an acceptable direct 1:1 substitution without altering the final set, though it imparts a distinct aromatic profile. Granulated white sugar can be swapped for cane sugar without affecting the cooking time or viscosity, but dark brown sugar introduces molasses notes that overpower the bright flavor of the berries.
Testing for Doneness and Storage
Visual and textural cues indicate when the boiling process is complete; drag a wooden spoon across the bottom of the saucepan and observe if the trail remains clear for a brief moment before the hot liquid flows back. Pouring the finished hot mixture directly into clean glass jars creates a safe environment for refrigeration. Stored properly in the refrigerator, this jam maintains its quality for up to three weeks due to the high sugar content inhibiting microbial growth. Freezing homemade jam requires leaving at least a half-inch of headspace inside the container to accommodate expansion during the freezing process.