Jam is a product made by boiling fruit pulp with sufficient sugar to a reasonably thick consistency, firm enough to hold the fruit tissues in position. It can be prepared from a single or two or more kinds of fruits. Commercial Jams can be prepared from pieces of fruit, fruit scraping and pulp. Apple, pear, sapota, apricot, loquat, peach, papaya, karonda, carrot, plum, strawberry, raspberry, mango, tomato, grapes and muskmelon are used for the preparation of jams.

Jam is a very common product made out of fruits and vegetables that permit consumers to taste the fruits of their liking even during lean periods or when the fresh produce is expensive. These products also permit the diversification of the fruit used to avoid distress sales during the production season and to minimize post-harvest wastages. This practice of preparing Jam is very simple and could be attempted at household levels even in rural areas if adequate food safety-related precautions are put in place. Besides, there are several fruits that are not cultivated in large quantities to permit large-scale processing. Still, these fruits are novel enough to convert them into processed products like jam and present them to consumers.

The method of preparation of fruit jam is given in our previous blog and can be seen through Method of Fruit jam preparation

Proper and well-processed jam can be stored for 6-12 months. But sometimes improper processing and storage leads to spoilage of jam. Some of the problems in jam production are crystallization, sticky or gummy jam, premature setting, surface shrinkage and graining and microbial storage.

[Problems in jam-making]

The problems in jam preparation are described below.


The crystallization of jam can occur due to a higher concentration of sugar. The final product should contain 30-50% of invert sugar. If the invert sugar percentage is less than 30% then the cane sugar may crystallize and if its percentage is more than 50% then the jam will become a honey-like mass due to the formation of small crystals of glucose. Corn syrup or glucose may be added along with cane sugar to avoid crystallization.

Sticky or gummy jam

            The high percentage of Total Soluble Solid (TSS) in jam will cause gummy or sticky jam. This problem can be solved by the addition of pectin or citric acid or both.

Premature setting

            Premature setting of the jam may occur due to low TSS and high pectin content in the jam. This issue can be solved by adding more sugar. If sugar addition can’t solve the problem, then it can be controlled by the addition of a small quantity of sodium bicarbonate, which reduces the acidity of the jam and premature setting can be prevented.

Surface shrinkage and graining

          Storing the jam at low RH (%) and high temperature causes more moisture loss causing surface shrinkage and graining.

Microbial spoilage

            Moulds are the most important microbes causing spoilage to the jam during storage. They are destroyed if exposed to less than 90% humidity. Hence jam should be stored at 80% humidity. Mould growth can also be prevented by not sealing the filled jar and covering the surface of the jam with a disc of waxed paper. Because mould does not grow under open conditions than in closed spaces. Sulphur @ 50ppm in the form of KMS (Potassium metabisulfite) can be added to the jam, but when one is taking cans addition of SO2 is not recommended as it may cause blackening of the internal surface of the can. Yeasts are not a serious problem due to the high concentration of sugar.

Hence the proper processing and storage of jam can be advised to reduce the problems in jam production. by subhrajyoti's horticulture

Hello friends, I'am Dr. Subhrajyoti , from Odisha, India. I have completed my UG & PG from OUAT and Ph.D. from JAU. During my early year of teaching, I loved to provide important information to the young agriculturists and farmers. With the suggestions from my best friend Mr. S. R. Biswal, (Ph.D. Research Scholar; website designer & content editor of (blog &YouTube), I got interested to create such an amazing platform, where I can share my knowledge to a greater range of audience and also get enriched with new ideas and knowledge. I feel privileged to be in contact with you all. I would like to thank you all for your valuable support and encouragement through viewing my articles. I will always try my best to provide the quality and latest information on this website. Thank you….

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