MG, MF and MB kraft for paper bags: which finish wins for shopping, food and industrial sacks

When buyers say 'kraft paper for bags' they usually mean three very different products. The finish — Machine Glazed (MG), Machine Finished (MF) or Mill Bleached (MB) — determines everything that happens downstream: how the bag prints, how it tears, how it survives a wet counter, and how fast it runs through a bottomer at 350 bags per minute.

Machine Glazed (MG) — high-gloss one side

MG passes one side over a polished Yankee cylinder, producing a glossy, low-roughness surface ideal for flexo and offset print. This is the workhorse of shopping bags, premium retail and luxury food carriers. Typical grammage range: 60–100 g/m². Brown or bleached. Excellent printability, moderate tear.

Machine Finished (MF) — both sides equal

MF kraft has both sides finished by the calender stack. The surface is rougher than MG but more dimensionally stable and stronger in tear. Best for grocery bags, bakery bags and any application where both sides may be printed or exposed.

Mill Bleached (MB) — clean white food-grade

MB is fully bleached kraft, often ISEGA or BfR compliant for direct food contact. It is the standard for white McDonald's-style bags, premium bakery and grease-resistant variants. Typical grammage: 40–80 g/m². Higher cost, but mandatory where food contact regulations apply.

Don't forget porosity — the silent KPI

For valve sacks and cement bags, porosity (measured in Gurley seconds or ml/min) decides whether the product fills cleanly or blows dust out the seams. Spec it explicitly with your mill — never assume.

WeePaper sources MG, MF, MB and extensible sack kraft directly from European mills with consistent CD/MD tensile and ISEGA documentation. Send us your converting line specs and target end-use and we'll return three benchmarked options.