Kraft paper is used for everything from grocery bags and food packaging to shipping protection, construction moisture barriers, and medical sterilization pouches. Its unusual strength comes from the manufacturing process itself, which strips away most of the lignin (the natural glue holding wood fibers together) and leaves behind long, tough cellulose fibers. That strength, combined with its low cost and recyclability, makes kraft paper one of the most versatile packaging materials in the world.
Why Kraft Paper Is So Strong
The word “kraft” comes from the German word for strength, and the name fits. In the kraft pulping process, wood chips are cooked under high temperature and pressure in a solution of sodium sulfide and sodium hydroxide. This chemical bath dissolves the lignin that binds cellulose fibers together, leaving behind a pulp that yields roughly 50 to 55 percent of the original wood weight. The tradeoff for that lower yield is a paper with exceptionally long, intact fibers that resist tearing, puncturing, and moisture far better than mechanically processed paper.
The result is a material that can be made thin and flexible or layered into heavy, rigid sheets depending on the application. Kraft paper comes in both unbleached (the familiar brown color) and bleached white versions, with the unbleached variety retaining slightly more strength because the bleaching process shortens some fibers.
Food Packaging and Contact
Kraft paper is widely used to package flour, sugar, dried fruits, and vegetables. The food-grade version is FDA-compliant and certified for direct contact with consumables, covering products like sandwich wrappers, biscuit bags, chewing gum wrappers, frozen confection packaging, salt and pepper packets, sugar packets, and tea pouches. Bleached kraft paper serves similar roles where a cleaner white appearance matters, particularly for sugar and flour bags.
Food-grade kraft paper is also approved by the FDA for irradiation sterilization of up to 10 kGy of gamma radiation, meaning food packed in it can be safely sterilized without the packaging breaking down or leaching harmful compounds. India’s food safety authority requires that only virgin-grade (not recycled) kraft paper be used for direct food contact, and similar standards exist in most countries to prevent contaminants from recycled fibers reaching food.
Shipping and Protective Packaging
Inside shipping boxes, kraft paper serves as void fill and cushioning material. Heavy-duty kraft dunnage rolls prevent products from shifting during transit and absorb shock to protect fragile, bulky, or sharp items. These rolls come in a range of weights, from 30-pound to 60-pound basis weight, so shippers can match the paper’s thickness and rigidity to the load. Lighter weights work for filling empty space around small items, while heavier weights cushion dense or breakable goods.
Kraft paper’s flexibility matters here. It can be crumpled, folded, or fanned into shapes that conform around irregular products, something rigid foam inserts can’t do as easily. And unlike plastic bubble wrap or foam peanuts, used kraft dunnage is recyclable curbside in most municipalities.
Grocery and Retail Bags
The classic brown paper grocery bag is kraft paper. Standard retail kraft bags are rated to carry 57 pounds or more, which is enough for a full load of groceries. Handles are now common, and the bags hold up well against sharp corners from boxed items that would puncture thinner materials. Consumer reviews consistently rate kraft bags as more durable than standard plastic alternatives for heavy or bulky purchases.
Construction and Moisture Control
In construction, laminated kraft paper functions as a vapor retarder and floor protector. Sheets reinforced with fiberglass offer rip-stop protection that resists tearing during installation, and the lamination provides higher water resistance than standard red rosin paper or thin construction paper. Builders lay these sheets under flooring, behind walls, or over subfloors during construction to control moisture migration and protect finished surfaces from foot traffic and debris.
Medical Sterilization Pouches
Medical-grade kraft paper is used to make self-adhesive sterilization pouches for tools and instruments. These flat pouches work with both steam autoclaves and dry-heat sterilization cabinets. Each pouch includes a built-in color indicator that shifts from purple to green when sterilization is complete, giving a quick visual confirmation. The pouches maintain a sterile barrier during transportation and storage, though any pouch exposed to moisture is considered compromised and must be discarded, even after drying. This strict standard reflects how effectively kraft paper’s porous structure allows steam penetration while still blocking microbial contamination once sealed.
Recycling and Composting
Kraft paper’s environmental profile is one of its biggest advantages over plastic alternatives. Paper and paperboard had a recycling rate of 68.2 percent in the United States in 2018, up from 42.8 percent in 2000. Paper products accounted for roughly 67 percent of all recycled municipal solid waste that year, making them the most recycled material category by a wide margin.
Uncoated kraft paper is also compostable. Under proper composting conditions with adequate moisture, aeration, and temperature, cellulose fibers in paper products fully biodegrade in 12 to 15 weeks. That timeline applies to well-managed compost operations. In a backyard pile with less consistent conditions, breakdown takes longer, but plain kraft paper without plastic coatings or heavy inks will still decompose. Coated or laminated kraft paper (like the fiberglass-reinforced construction version) is not compostable and should go through standard recycling or waste streams instead.