What is kraft paper.
Kraft paper is strong paper made from wood pulp by the kraft process, the brown paper of carrier bags, sacks and wrapping. This page explains where the name comes from, how the paper is made, and why it is strong enough to carry a load.
The short answerKraft paper is made from wood pulp produced by the kraft process, which cooks wood chips in caustic soda and sodium sulphide. The name is the German word for strength. Unbleached kraft is brown, and bleached kraft is white.
Why it is called kraft
Kraft is the German word for strength. Carl F. Dahl of Danzig patented the process in 1884, and its pulp was stronger than the soda pulp made before it.
What makes it strong
The cooking dissolves most of the lignin, the natural glue that holds wood together. With less lignin, the cellulose fibres bond tightly to each other, and that bond carries the weight in a bag.
Brown kraft and white kraft
Brown kraft
Unbleached. The natural colour of the pulp, and the stronger of the two.
White kraft
Bleached. A clean base for bright colours and pale inks.
Bleaching weakens the fibres and costs some of the pulp, so white kraft gives up a little strength for its colour.
On a printed bag the choice is about colour. Brown kraft warms whites and yellows, so pale colours print truest on white kraft.
Kraft paper weights for bags
Paper weight is given in grams per square metre, or gsm. Our kraft carrier bags run from 80 to 270gsm: the light weights for takeaway, the heavy ones for retail with rope handles. Block bottom SOS bags are 70 to 100gsm.
More on paper weight in What is gsm, and the bag itself on the Kraft Paper Bag page.
Questions
Why is kraft paper brown?
It is unbleached. The pulp keeps its natural brown colour, and bleaching it white costs some strength.
Is kraft paper recyclable?
Kraft paper with no plastic film goes in ordinary paper recycling. Our kraft bags have no lamination, and with paper handles the whole bag goes in the paper stream.
Is kraft paper food safe?
Food contact depends on the grade, not the name. Our food grade bags use food contact compliant kraft, with certificates on request.
What is kraft paper made of?
Wood pulp, cooked in caustic soda and sodium sulphide to free the fibres from the lignin that binds them.
Why is it called kraft paper?
Kraft is German for strength. The kraft process makes a stronger pulp than the methods before it.
Written by the Bag Bureau production team. Last updated October 2026.