Greaseproof Kraft Paper Bags for Food: What to Check Before Ordering

Hand a customer a bag of hot chips and the paper either holds or it goes translucent within two minutes. Everyone in food service has seen the second version. Greaseproof is one of those words printed on nearly every kraft bag in the market, yet the performance behind it varies enormously depending on how the resistance was achieved. Buyers who ask two or three specific questions before ordering tend to avoid the greasy, semi-transparent bag that ends up double-bagged by staff and quietly damages how a brand is perceived.

What Greaseproof Actually Means

Resistance comes from one of two places. The first is refining: fibres beaten until the sheet becomes dense enough that oil penetrates slowly. This is genuine grease resistance built into the paper itself, with no added coating. The second is a barrier layer applied to the surface — polyethylene extrusion, wax, or a fluorochemical-free dispersion coating. Refined paper breathes and feels natural but reaches a ceiling of resistance. Coated grades go much further and are what most hot fried applications require. A bag sold simply as greaseproof may be either, and the difference shows up in real use.

How Resistance Is Measured

The industry relies on standard test methods rather than adjectives. TAPPI T454, the turpentine test, measures how long a penetrating fluid takes to pass through a sheet. TAPPI T559, widely called the Kit test, rates surface repellency on a scale where higher numbers mean better resistance against progressively more aggressive oil mixtures. Asking a supplier for a Kit rating turns a vague claim into a comparable number. A bag rated 3 handles a muffin; a bag rated 8 or above handles fried food straight from the fryer. Request the test report, not the brochure claim.

Coating Options and Their Trade-offs

Polyethylene extrusion delivers strong grease and moisture resistance and heat sealability, at the cost of making the pack harder to recycle in paper streams. Wax coatings are traditional for bakery and confectionery and give a distinctive feel, but soften under heat. Water-based dispersion coatings have largely replaced fluorochemical treatments as regulations tightened around PFAS substances, and they offer a workable middle ground with better repulpability. Each option shifts cost, heat tolerance and end-of-life handling. A manufacturer should be able to explain which coating a given grade uses and why.

Where These Bags Get Used

Bakery counters use them for croissants, cookies and pastries where light grease meets a warm surface. Fried chicken, chips and samosas need the higher end of the resistance scale. Sandwich shops want a bag that holds moisture without soaking through during a lunch rush. Confectionery and chocolate need grease resistance more for fingerprint oils and cocoa butter bloom than for liquid fat. Popcorn, pretzels and roasted nuts round out the list. Industrial uses exist as well — greasy hardware parts and mechanical components ship in the same construction.

Heat, Cold and Microwave Behaviour

A coating that holds at room temperature can fail at 60°C, which is roughly the surface temperature of freshly fried food. Always test with the product at serving temperature, not cooled. Freezer applications behave differently again: condensation during thaw wets the sheet and any barrier must survive rewetting. Microwave use is a separate specification entirely and most standard greaseproof bags are not rated for it. If a customer might reheat food in the bag, that requirement needs to be stated upfront so the factory can propose a suitable structure.

Compliance Documents to Request

Food contact paper must be supported by documentation, not assurance. In the United States, relevant clearances appear under Title 21 of the Code of Federal Regulations, including parts covering paper and paperboard components and coating substances. In the European Union, Regulation (EC) No 1935/2004 sets the framework for all food contact materials, with national provisions covering paper specifically. Rising scrutiny on PFAS has made per- and polyfluoroalkyl substance declarations a routine request. A credible supplier provides declarations covering the base paper, the coating and the printing inks.

A Short Checklist Before You Buy

Confirm grammage, typically 35 to 80 gsm for food service bags. Confirm whether resistance comes from refining, coating, or both. Ask for the Kit or turpentine test result at the temperature you will actually use. Check bag style — flat, SOS block bottom, pinch bottom, or window bag — against how staff load and close it. Verify printing ink is low-migration and, for direct food contact areas, food-safe. Order samples and run them with hot product for a full service period. Five minutes of testing beats a thousand dollars of returns.

Storage and Handling on Site

Paper is hygroscopic and reacts to the room it sits in. Cartons kept in a damp storeroom produce bags that curl, jam dispensers and lose stiffness right when service gets busy. Keep inventory dry, away from steam lines and cleaning chemicals, rotate stock, and avoid opening cartons hours before they are needed. Dispenser compatibility deserves a check too: a bag that releases cleanly from one dispenser may not from another, and the difference usually comes from surface friction rather than grammage. Ask the supplier for dispenser guidance before rolling a new bag out across multiple outlets, because a specification that works in one site can stall in the next.

References

TAPPI. (2023). TAPPI T 454: Turpentine Test for Grease Resistance of Paper. Technical Association of the Pulp and Paper Industry.
TAPPI. (2022). TAPPI T 559: Grease Resistance Test for Paper and Paperboard, Kit Test Method. Technical Association of the Pulp and Paper Industry.
European Parliament and Council. (2004). Regulation (EC) No 1935/2004 on materials and articles intended to come into contact with food. Official Journal of the European Union.
U.S. Food and Drug Administration. (2024). Guidance for Industry: Food Contact Substances. Center for Food Safety and Applied Nutrition.
Institute of Packaging Professionals. (2023). Paper-Based Food Packaging: Performance and Compliance Overview. IoPP Educational Resources.