Side-gusseted bag

A side-gusseted bag has inward folds, or gussets, along both sides. As it fills, the gussets open out and the bag gains an almost rectangular cross-section. Most versions have a long back seal and a straight bottom seal.

Where it is used

It is the classic coffee bag, and is also common for tea, loose spices, flour and bread mixes, pasta, pet food, cat litter and agricultural or industrial granules.

Advantages

• High volume for relatively little material.
• Simpler and usually cheaper to make than flat-bottom or quad-seal formats.
• Can be closed by heat seal, folded with a tin tie, or labelled.
• Available as a pre-made bag or formed from rollstock on a vertical machine.

Points to consider

The back seal usually runs down the centre of the rear panel, so the artwork must allow for it. Gusset depth should suit the product volume. On its own the straight bottom is not very stable; for a firmer stance, compare a quad-seal pouch. Coffee will usually need a one-way degassing valve to prevent the bag from inflating.