How to Spec Paper Bag GSM and Bottom Construction

Quick answer

Write paper bag GSM together with paper grade, bag dimensions, gusset, bottom style, handle reinforcement, and target load. GSM alone does not predict a bag’s carrying performance because fiber quality, glue area, and bottom geometry can dominate failure.

Define the paper properly

State virgin or recycled kraft, bleached or natural color, GSM tolerance, and required strength measures if critical. Large bags and wet-use conditions often need a stronger grade or construction, not merely higher nominal GSM. Approve production paper samples when shade or surface feel matters.

Understand bag geometry

Record face width, side gusset, finished height, and whether dimensions are internal or external. A wider gusset changes bottom load distribution and stacking. Give suppliers a filled-product drawing when cartons, bottles, or food containers must fit with a clearance target.

Bottom styles

Square-bottom bags use folded and pasted panels; flat-bottom or SOS formats may include a separate bottom reinforcement. Specify glue pattern expectations and whether bottom board is required. Sharp or heavy products need a practical drop and carry test, not just visual inspection of the seam.

Handles and patches

Handle pull transfers force into the upper panel. Define patch material, patch size, glue coverage, and handle centerline. Increasing GSM without strengthening the patch can simply move the failure from the bag wall to the handle joint.

Validation method

Load real products to the agreed mass, carry for a defined time, and inspect handle pull, bottom opening, tearing, and print scuff. Condition samples at the expected humidity when bags travel or operate in damp markets. Agree the sample quantity and reject criteria before bulk.

RFQ fields

Finished bag dimensions and dimensional tolerance

Paper grade, GSM, color, and recycled-content rule

Bottom style, glue/reinforcement requirements

Handle type, patch details, target load and test

Print, quantity ladder, export packing, Incoterms

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Twist-Handle vs Flat-Handle Paper Bags for Retail, How to Check Recyclable Packaging Claims from Suppliers, How to Request Packaging Samples from China Factories, Folding Cartons from China: Sourcing Guide.