As global demand for sustainable packaging grows, jute bags have become a preferred solution for businesses seeking durability and eco-efficiency. Produced from 100% natural fibre, jute offers strength, breathability, and biodegradability, making it ideal for agriculture, retail, and industrial use.
Behind every export-ready jute bag is a structured manufacturing process that ensures consistent quality and performance. From raw fibre selection to spinning, weaving, cutting, and stitching, each stage is carefully managed to meet international standards.
This guide outlines the complete jute bag manufacturing process and highlights how modern production techniques allow customization through printing, dyeing, and branding. It provides clear insight into how natural fibre is transformed into a reliable, market-ready product that aligns with global sustainability goals.
Understanding Jute as a Raw Material
The quality, durability, and end-use of jute products are largely determined by the properties of the raw fibre and its origin. Before entering the production cycle, it is essential to understand the physical attributes of jute, where it is grown, and how fibre quality varies by application.
Properties of Jute Fibre
Jute fibre is derived from the outer layers of the Corchorus plant and is valued for its tensile strength, breathability, and biodegradability. It is composed mainly of cellulose and lignin, offering durability while remaining fully compostable in natural conditions. Its resistance to UV degradation and its anti-static properties make it suitable for both industrial and consumer applications. Unlike synthetic fibres, jute allows air flow, which is especially beneficial for agricultural storage.
Difference in Fibre Quality for Sacks and Promotional Bags
Jute intended for industrial sacks requires thick, coarse fibres with high tensile strength to withstand load stress. In contrast, jute used for fashion or promotional bags demands finer, more pliable fibres suitable for dyeing, printing, and branding. Fibre grading during the drying stage determines this allocation, with higher-grade fibres routed to textile-quality production and lower grades to heavy-duty applications.
Jute Sack Manufacturing: Step-by-Step Process
Jute sacks are strong, eco-friendly bags used for carrying bulk materials like grains, sand, and cement. Their production begins in the field and continues through several technical steps until they are ready for packaging and export. Below is a clear breakdown of the full process.
Step 1: Growing and Harvesting the Jute Plant
Jute is mostly grown in India and Bangladesh. It is planted between March and May and harvested after 100 to 120 days, once the plants grow to about 10 to 12 feet tall.
Harvesting: Farmers cut the stalks near the ground using sickles to keep the full fibre length intact. This helps ensure the fibre is strong enough for sack production.
Step 2: Extracting the Fibre from the Stalk
- Retting: The cut stalks are tied in bundles and soaked in ponds or rivers for 10 to 20 days. This soaking process is called retting. It helps loosen the fibre from the wooden part of the plant.
- Stripping and Washing: After soaking, workers strip the fibre by hand. The fibre is then washed in clean water to remove dirt and leftover plant matter.
- Drying and Sorting: The washed fibre is laid out in the sun to dry for several days. Once dry, it is sorted by length, strength, and color. Coarser, stronger fibre is selected for jute sacks because it can carry heavy loads.
Step 3: Turning Jute Fibre into Yarn
After drying and sorting, the raw jute fibres are sent to mills where they are processed into yarn. This yarn is the base material used to weave the heavy cloth needed for jute sacks.
- Softening the Fibr: Before spinning, the dry fibres are sprayed with a light oil and water mixture. This makes them soft and flexible so they move smoothly through the machines.
- Carding and Drawing: The fibres are then passed through carding machines. These machines untangle the fibres and align them into thin, even sheets. These sheets are drawn and layered to make the fibre more uniform and easier to spin.
- Spinning into Yarn: The drawn fibre is finally spun into yarn using spinning frames. The machines twist the fibres together to create strong, thick yarn. The thickness and strength of this yarn are made to match the needs of sack fabric, which must carry heavy loads without breaking.
This yarn is now ready to be woven into the thick sacking cloth used to produce industrial-grade jute sacks.
Step 4: Weaving Yarn into Sacking Fabric
Once the jute yarn is ready, it is woven into thick cloth known as sacking fabric. This fabric must be strong, dense, and durable because it will be used to make sacks for carrying heavy materials.
- Preparing the Looms: The spun yarn is loaded onto large weaving machines called power looms. These machines are set to create a tight weave that holds up well under pressure.
- Weaving the Fabric: The looms weave the yarn into long rolls of fabric. For jute sacks, the weave is coarse and heavy. This type of fabric is usually between 10 and 14 ounces per square yard, depending on what the sack will be used for.
- Finishing the Fabric: After weaving, the fabric may go through a pressing process to flatten it and remove loose fibres. This makes it easier to handle in later steps and helps prevent shedding during use.
The finished sacking fabric is now strong enough to be cut and sewn into jute sacks.
Step 5: Cutting the Fabric into Sack Panels
After the sacking fabric is woven and finished, it is ready to be cut into panels that will form the body of each sack. This step must be done accurately to make sure all sacks are the same size and shape.
- Measuring the Fabric: The rolls of fabric are unrolled and measured based on the required sack dimensions. A common size for jute sacks is 100 cm in length and 60 cm in width, but this can vary depending on the customer or industry need.
- Cutting the Panels: Workers use large shears or industrial cutting machines to cut the fabric into panels. The cuts must be straight and consistent so that the sacks can be sewn properly in the next step.
- Choosing the Sack Style: There are two main styles of jute sacks:
- Tubular sacks are made by folding the fabric so that only the bottom and one side need stitching.
- Flat-cut sacks are made from separate panels and stitched on all sides.
The choice of style depends on how the sack will be used and how the customer wants it to be filled.
Once the panels are cut, they are stacked and moved to the stitching section for final assembly.
Step 6: Stitching and Assembly
With the fabric panels cut and ready, the next step is to sew them into complete jute sacks. This process must be done with strong thread and careful stitching to ensure the sacks can carry heavy materials without tearing.
- Sewing the Seams: The panels are stitched together using heavy-duty industrial sewing machines. Workers use strong jute or synthetic thread to make the seams durable.
- Side seams are stitched using overlock or chain stitch methods.
- Bottom seams are folded and stitched for extra strength, so the base does not split under weight.
- Types of Sack Openings: There are two main types of sack openings, depending on how the sack will be filled:
- Open-mouth sacks are left open at the top and are tied or sewn shut after filling.
- Valve sacks have a small opening that lets machines fill the sack quickly and cleanly. These are common in cement and fertilizer packaging.
- Reinforcing the Sacks: For sacks that need to carry extra heavy loads, extra stitching or double seams may be added to high-stress areas.
Once the stitching is complete, the sacks are inspected and stacked for final testing before packing.
Step 7: Testing for Quality and Strength
Before the jute sacks can be packed and shipped, they must go through quality checks to make sure they are strong, safe, and meet the size and weight standards required for their intended use.
- Checking the Size and Shape: Each sack is measured to confirm it meets the correct length and width. Even small differences in size can cause problems during filling, stacking, or transport.
- Testing the Fabric Strength: Samples from each batch of sacks are tested to see how much weight or pressure they can handle. These tests include:
- Burst strength tests to check how much force the fabric can take before it tears.
- Seam strength tests to make sure the stitches hold when the sack is full.
- Drop tests where filled sacks are dropped from a set height to check for damage.
Moisture Check: The sacks must also be dry. If they contain too much moisture, they can develop mold or weaken during storage. Moisture levels are measured and must stay below a safe limit, usually around 14 percent.
Only the sacks that pass all these checks are approved for packaging and shipping.
Step 8: Packing and Preparing for Shipment
Once the jute sacks have passed all quality checks, they are packed in bundles and prepared for delivery to customers or export destinations.
- Making Bales: Sacks are counted and packed into large compressed bundles called bales. Each bale usually contains 100 or 200 sacks, depending on their size and thickness. The bales are tightly tied with jute or plastic straps to keep them secure during transport.
- Labeling the Bales: Each bale is labeled with important details such as:
- Sack size and weight
- Quantity inside the bale
- Production batch number
- Manufacturer or exporter information
- Preparing for Export: If the sacks are being shipped internationally, extra steps are taken to meet export requirements. These may include:
- Moisture protection, using plastic wrap or desiccant packs
- Fumigation or pest control certificates
- Compliance documents like tensile strength test results or export inspection reports
- Storage: Before shipping, bales are stored in dry, well-ventilated warehouses. This prevents moisture damage and keeps the sacks in good condition until they are loaded onto trucks or containers.
This completes the full jute sack manufacturing process, from growing the plant to producing, testing, and shipping industrial-grade sacks.