Jam filling is a crucial process in the entire jam production process. Precisely and cleanly filling jam without any clogging is a significant challenge. If you want to improve the production efficiency of your jam products and minimize their defects, please read this article to learn about the factors to consider in the jam filling process.
Characteristics of Jam Products
Jam products are semi-solid gel foods primarily made from fruits, sugar, and pectin through boiling and concentration. Their viscosity varies widely, from low-sugar jams with good fluidity to extremely viscous traditional jams rich in pectin, so filling different types of jam needs different pumping pressures and metering methods.
Jam often contains solid particles, such as fruit pieces, which need to remain intact and evenly distributed during the filling process. Most jams use hot filling for sterilization and preservation, while some heat-sensitive jam products may use cold filling with pasteurization. These two methods have different requirements for the filling equipment.
The natural pigments, aroma compounds, and vitamins in jam are highly sensitive to oxygen. Oxygen can make jam fade in color and lose its flavor, so the contact between the jam and air should be reduced as much as possible. The jam container must be completely sealed, and the headspace should be as small as possible.
What to Consider when Filling Jam
Accuracy And Consistency
Ensuring every jam product has a precise and consistent filling volume is a major challenge. Jams are typically thick, and their viscosity changes with temperature and uneven distribution of fruit pieces. For jam products with high value, even a light overfill can waste a lot of raw materials in large scale production.
If the filling is insufficient, consumer complaints will arise, and it’s also non-compliant. Therefore, filling accuracy significantly influences your production costs and reputation. Jam filling machines must be equipped with metering systems with high precision to ensure that the weight or volume of each container is highly consistent, thereby controlling costs and building reputations.
Integrity of Jam Products
High-quality jam has a silky and smooth texture and plump fruit pieces. Â You should take care to avoid the fruit pieces and the overall texture of the jam from being damaged. If the fruit pieces are excessively sheared or squeezed during filling, they will break and deform, affecting the jam’s appearance and taste.
Besides, the jam may absorb too much air due to mechanical agitation, or problems such as fruit particle sedimentation and uneven distribution may occur after filling. Therefore, the filling system should take care to protect the jam, ensuring that its color, shape, and texture remain intact after it is dispensed from the tank into the container. This can be achieved by technologies such as wide-channel, low-shear piston pumps or in-line mixing tanks.
Health And Safety
As a product consumed directly by customers, jam filling should comply with strict hygiene and safety standards. The entire filling system, especially the parts that come into contact with the product, must be made of food-grade materials, such as 316L stainless steel.
Filling machines must be designed for the ease of thorough cleaning and sterilization, and the blind spots must be eliminated. For jam products handled by hot filling, the filling temperature must be consistently and stably maintained above the threshold sterilization temperature, typically >85°C.
Besides, the filling environment must be clean and sterile to prevent secondary microbial contamination. The product container must be tightly and reliably sealed to ensure that an effective vacuum is formed after the jam product cools down, and the shelf life of the jam products is reasonable.
Filling Efficiency
The filling efficiency of jam directly determines the output capacity and operating costs of the entire jam production line. The high filling efficiency not only means that the equipment can fill more containers per unit time, but also is beneficial to the smooth and stable operation of the entire jam production line.
The filling process needs to be seamlessly integrated with upstream processes such as material supply and preheating, as well as downstream processes like capping, cooling, and labeling, and the inefficiency in the filling stage can become a bottleneck in jam production.
The stability and reliability of the equipment are crucial factors that affect jam filling efficiency, so you should reduce unplanned downtime caused by malfunctions such as blockages as much as possible. You can also improve the overall efficiency of the equipment by optimizing the production cycle.
Production Flexibility
Jams have various flavors and types, and their market demand is diverse, so jam filling systems need to be highly flexible and able to quickly switch between different products, from large-particle strawberry jam to smooth low-sugar jam, and the cleaning and adjustment processes during product changeovers should be simple and quick.
Jam filling machines should also be able to adapt to packaging containers of various sizes and shapes, such as glass jars and plastic bottles of different diameters, and their adjustments of parameters and mold changes should be convenient. Besides, if the jam recipe is adjusted in the future, such as changing the jam viscosity, the filling system should be able to adapt.
A flexible filling system allows manufacturers to respond promptly to market changes, produce small batches of jams of different varieties, and shorten the time to market for new products.
Two Main Types of Filling Systems
Volumetric Filling
Volumetric filling measures the amount of jam dispensed into each container by controlling the volume. These jam filling machines typically use high-precision piston cylinders or constant-volume pumps. By setting the movement of the piston or the number of pump rotations, the jam is divided into predetermined volumes and filled into containers. These mechanical structures are relatively straightforward and highly efficient.
However, the accuracy of volumetric filling can’t be achieved without stable jam density and viscosity. If the density of the jam is changed by its fluctuations in viscosity, temperature, or fruit content, the actual weight of the same volume of jam will be different. Therefore, volumetric filling is more suitable for jam products with stable formulas and uniform textures.
Weight-Based Filling
Weight-based filling directly controls the weight of the jam during filling. It measures the weight of each container in real time during the filling process and uses a feedback control system to make precise adjustments as the product approaches the target weight until it is achieved.
This method can achieve high jam filling accuracy by avoiding the effects of changes in jam density, viscosity, or air bubble content. It is particularly suitable for jam products with high value, strict regulatory requirements, or large fluctuations in fruit content.
Although weight-based filling may be slightly slower than volumetric jam filling and its equipment cost is usually higher, it can reduce waste, ensure compliance, and handle products with different densities or viscosities.
Jam Filling Process
Preparations before Filling
Thorough Machine Cleaning
Jams are typically thick, and even the least viscous jams are thicker than liquids, so they are prone to leaving residues on the filling machine. Besides, jam is perishable, so the machines must be thoroughly cleaned before production to prevent contamination and ensure your jam products are safe and of good quality.
The filling nozzles and spouts of the filling machine should be cleaned to prevent them from being blocked. The operators should also clean filling tanks and hoses to prevent jams from piling up inside them. Other things, such as conveyors and jam containers, should be thoroughly sterilized to eliminate potential contaminants.
Machine Calibration And Inspection
Before the formal filling, you should adjust the filling machine to the required volume or weight of the jam product and make sure the amount of jam filled into each container is the same. This step is particularly important for the method of volumetric filling because even small changes can lead to overfilling or over-filling for it.
Besides, the operators should check the wear and tear of all the moving parts, such as belts, gears, and sealing components. Their wear and tear can also affect filling accuracy. The filling will be uneven, the efficiency will be reduced, and the downtime will increase if the machine breaks down.
Jam Preheating
During the filling process, the jam must be at a consistent temperature to maintain the consistency of its viscosity, because the jam’s viscosity is usually influenced by its temperature. Hotter jams have a greater fluidity, and cooler jams are thicker and more difficult to dispense. Therefore, the jam has to be preheated to a certain temperature before it is filled.
To maintain consistency, jams are typically kept at a temperature between 85°C and 95°C. A more precise temperature is determined by the ingredients of the jam. To ensure smooth and efficient filling, the temperature of the jam must be accurately monitored and controlled.
Operations during The Filling
Preheated jam is pumped through insulated pipes to heated buffer tanks or a feeding system to maintain its appropriate viscosity and ensure its smooth flow. The jam needs to be continuously and gently stirred to prevent fruit particles from settling and to prevent uneven temperature distribution. In the crucial filling stage, the jam must be dispensed while still at a high temperature to ensure product safety.
According to the preset volume or weight, the jam with high temperature, thick texture, and may contain particles, is precisely injected into sterilized containers through pistons, peristaltic pumps, and other mechanisms. Dripping, stringing, and container mouth contamination must be prevented during filling.
The immediate sealing after filling is crucial. Jam containers should be quickly screwed on or capped to prevent contamination, and the vacuum created during the subsequent cooling process will help enhance the reliability of the seal and extend the shelf life of the jam products.
After filling, the jam products are immediately inverted by the inverting device, using the residual heat of the jam to instantly sterilize the inner wall of the bottle cap.
Post-Filling Operations
Cooling of Jam
If jam products are not cooled in time, prolonged high temperatures can cause the flavor and color of the jam to deteriorate, and the jam container deformation. Rapid cooling allows the jam to solidify into a gel and creates a vacuum within the container, helping to maintain the jam’s quality and consistency.
Cooling tunnels or controlled air cooling systems are typically used to cool the jam to a safe temperature for the ease of subsequent labeling, packaging, and handling. For jams with low sugar and low acid, rapid cooling shortens the time the product spends at dangerous temperatures, typically 4-60°C, effectively inhibiting microbial growth, which is crucial for food safety.
The cooling system needs to be maintained regularly, and the cooling temperature and method are decided by the type of jam and container. For example, if the jam is packaged in glass bottles, rapid cooling may make the glass break. Therefore, cooling is usually carried out in stages or gradually. This also prevents large temperature differences between the surface and center of the jam, which could affect its texture.
Quality Inspection
The filled and sealed jam products have to undergo a series of tests to ensure that the products entering the market are stable, reliable, and meet quality and food safety standards. Common testing items include visual inspection, filling weight or volume testing, sealing integrity testing, vacuum level testing, and sample opening and testing. Some production lines are equipped with metal detectors or X-ray inspection equipment to prevent foreign objects from being mixed in.
Manual visual inspection or machine vision systems can quickly identify products with obvious defects. The online automatic checkweigher can weigh the filled jam jars in real time. The tightness of the bottle cap can be evaluated using a torque test. Vacuum level is measured using a specialized instrument to determine the vacuum in the headspace of the bottle.
In addition, complete samples can be regularly sent to a laboratory to be opened for deeper analysis and inspection, such as more precise measurement of the filling volume.
Cleaning Machine
After the jam filling process is complete, the tanks, pipes, filling heads, and related conveying systems should be cleaned in time to thoroughly remove any remaining jam residue, preventing it from solidifying, growing microorganisms, and affecting subsequent production. This process is typically performed automatically through a CIP (Clean In Place) system.
The main CIP process is to circulate hot water or an alkaline cleaning solution to dissolve and rinse away viscous sauce residue. This is followed by rinsing with clean water, then using an acidic cleaning agent to remove scale, and finally, if necessary, using a disinfectant for sterilization.
Jam Filling Machines
Different jam products need to be handled by different jam filling machines. Here are some typical models.
Piston Filling Machine for Jam
Piston filling machines use the movement of a piston within a cylinder to fill a precise volume of jam. They are suitable for handling jams with medium to very high viscosity, and are particularly good at handling jams containing large fruit pieces. They can effectively prevent fruit pieces from being sheared or crushed to maintain product integrity.
The piston fillers are highly adaptable and can adjust the jam filling volume by changing the piston cylinders of different sizes. They also have high filling accuracy, which makes them a great choice for producing jams requiring high precision and high quality.
Peristaltic Pump Filling Machine for Jam
The working principle of a peristaltic pump filling machine is to use rollers to repeatedly squeeze an elastic hose to push the jam inside the tube forward to achieve jam filling. The only part of the machine that comes into contact with the jam is a single flexible tube, making product changeovers and cleaning very convenient, fast, and thorough.
This design perfectly prevents cross-contamination, but the tube needs to be replaced periodically as a consumable part. Peristaltic pump filling machines are suitable for filling jams of medium viscosity without large particles. They are ideal for production lines processing small batches and multiple varieties of jam.
Gravity Filling Machine for Jam
Gravity filling machines rely on gravity to achieve filling. Â The jam flows naturally from a high-positioned storage tank through a filling valve into the containers below. They have a simple mechanical structure, which is easy to operate and maintain. Their manufacturing cost is also relatively low.
However, the filling accuracy and speed of the machine are highly dependent on the viscosity and fluidity of the jam, making it more suitable for jams with low viscosity and uniform texture. For jams with high viscosity or containing fruit particles, using gravity filling machines can lead to slow filling speeds, inconsistent accuracy, and dripping.
Vacuum Filling Machine for Jam
The vacuum filling machine first creates a vacuum inside the jam container, and then uses the pressure difference between the atmospheric pressure and the pressure inside the container to push the jam from the storage tank into the container until the preset jam amount is reached. This filling method is extremely stable, produces almost no bubbles, and is very precise.
Vacuum filling machines are particularly suitable for jams that easily form bubbles and for jam containers that require complete filling. However, they are only suitable for the jam containers with high sealing and rigidity, such as glass bottles or metal cans. Containers easy to deform under vacuum, such as soft plastic bottles, cannot meet their production requirements.
FAQ
What Factors Determine The Viscosity of Jam besides Temperature?
In addition to temperature, the viscosity of jam is also determined by other factors. The solids content and fiber of fruit are the main components of jam. The higher the fruit concentration, the firmer the jam. The ratio of sugar to fruit is also crucial. The higher the sugar content of the jam, the more water it absorbs, resulting in a thicker and shinier jam. Finally, the amount and type of pectin added to the jam can adjust its texture, from soft to firm.
How to Minimize Viscosity Fluctuations of Jam?
You can use continuous monitoring systems to check any changes in the jam’s fluidity. The system is installed directly in the delivery pipeline before filling. It continuously measures and feeds back viscosity data to the central control unit.
Once a viscosity deviation is detected, the system can automatically adjust filling parameters in real time, such as the speed of the piston, the rotation speed of the pump, or the opening time of the filling valve, without manual intervention.
How to Handle Jam Containers of Different Types And Shapes?
Regardless of the types of containers, inspect them first to ensure there are no defects. They can be visually inspected or subjected to a simple drop test. The jam containers should be positioned correctly on the filling line. The machine can use special holders or guides to prevent them from moving, tipping over, or breaking. The filling machine should be calibrated according to the exact size and shape of the container.
What Are The Differences in Cleaning The Machine before And after Filling?
Pre-filling cleaning is a preparatory step for production. It is responsible for eliminating potential sources of contamination and performing necessary disinfection. This ensures the machine is hygienic before startup and prevents residues from previous batches or environmental contamination from affecting the quality of the new product.
Post-filling cleaning focuses on removing residual jam, sugar, and fruit particles left over from the production process to prevent material from drying and clogging the equipment or promoting microbial growth.
What Hygiene Regulations Should Jam Filling Operators Follow?
Jam filling operators should avoid direct contact with jam products and their packaging materials and wash and sanitize their hands regularly. They should also wear appropriate protective clothing, such as clean uniforms, hairnets, gloves, and masks. Before and after production, operators must promptly clean and disinfect the filling equipment.
In addition, operators should regularly participate in hygiene training and report any illnesses or contamination risks in time to prevent violating GMP (Good Manufacturing Practice) and local food safety standards.
What Are The Benefits of Using A Jam Filling Machine?
With the help of the jam filling machine, the amount of jam dispensed into each container is accurate and consistent, which saves the jam product and prevents waste. The amount of manual labor required for filling jam products has also been reduced, thereby lowering labor costs and reducing human error. The machine can adapt to different jam viscosities, fruit pieces, and container sizes, to achieve quick product changeovers.
What Are The Common Issues And Their Causes When Filling Jams?
If the jam is being filled unevenly, it may be caused by a change in the jam’s viscosity or the air being trapped in the jam during filling. If there are leakage problems with the jam products, it may be because there is a problem with the container seal, or the filling head is not properly aligned during filling. If the jam sticks to the machine and causes blockages, it could be caused by insufficient preheating or residue from the previous batch of jam.
Final Thoughts
Jam filling may seem simple, but it involves many considerations, regulations, and technical details. You can contact JOCHAMP; our experts are always ready to answer your questions, recommend the most suitable filling solution, and help you avoid practices that violate regulations or disrupt production. We will help you achieve smooth and clean jam filling production.