Home-Style Strawberry Jam Making Techniques and Methods

Strawberry jam has a rich aroma and an attractive color, and is often used as a sour seasoning in cooking. It is also very simple to make and can be prepared at home for personal consumption. The method is described below.

1. Process flow: raw material selection → washing → heating and concentration → filling into jars → sealing → sterilization → cooling → finished product

2. Key operating points

1. Raw material selection. Select fresh strawberries that are free of mold and rot, free of pests and diseases, and moderately ripe, about 80% ripe (red skin accounting for more than 70% of the skin area), with firm tissue that withstands cooking. Varieties with red or dark red skin, a high pectin content, high fruit acidity, and a rich aroma are best; there are no strict requirements on fruit size.

2. Washing. Pour the strawberries into running water and soak for 3-5 min, then divide small quantities into perforated baskets and wash clean in a running water trough, twist off the stems one by one, and remove the sepals.

3. Heating and concentration. (1) Formula: strawberries 100 kg, citric acid about 200 g, sorbic acid 75 g, granulated sugar 115 kg; before use, the granulated sugar needs to be made into a 75% sugar solution. (2) Concentration method: pour the strawberries into a jacketed kettle and add part of the sugar solution (half of the formula amount), so that the fruit pulp and sugar are fully mixed, then heat and concentrate; stir appropriately during heating to fully soften them, then add the remaining sugar solution, citric acid, and sorbic acid, and continue heating and concentrating until the soluble solids reach 66.5%-67%, then remove from the heat.

4. Filling into jars. Fill the jam into sterilized jars while hot, and each batch of jam should be filled within 20 min. Headspace should be left, with the distance between the contents and the jar lid at 6.4-9.6.

5. Sealing. The temperature during sealing should preferably be above 85°C, in order to isolate the strawberries from contact with the outside and prevent secondary contamination.

6. Sterilization. For tinplate cans with a net mass of 343 kg, place them in 70°C water and heat until the water boils, then sterilize at 100°C for 15 min; glass jars should preferably be sterilized using a continuous steam heating sterilizer; for tinplate cans with a net mass of 454 g, heat in 70°C water until the water boils, then sterilize at 100°C for 20 min.

7. Cooling. After sterilization, cool immediately until the temperature inside the jar is preferably 38-40°C.

8. Finished product inspection. Quality requirements: the color should be purplish red or reddish brown, glossy, and uniform; the taste should be sweet and sour, with no burnt flavor or other off-flavors; the jam body should be viscous and may retain some fruit pieces; the total sugar content should be no less than 57%, and the soluble solids should reach 65% (refractometer).