S.O.S. vs block bottom paper bags: design differences

Paper bags are an indispensable lightweight, customisable and environmentally friendly packaging option in the retail and food industries. Different designs allow goods of various weights to be packaged, and impregnation or an additional layer protects the bag from grease and dirt when used for food delivery.

S.O.S. (self-opening square) bags and block bottom paper bags are two widely used formats in retail and food packaging. Each offers distinct advantages in terms of design, durability and branding potential. Although they have some structural similarities, the details of their construction influence their performance in practical use and their ability to be customised.

Design differences

S.O.S. bags are characterised by their rectangular base and side gussets, which enable the bag to open automatically when placed on a flat surface. This self-opening feature is achieved through a simple folded bottom construction that prioritises ease of use and quick filling. S.O.S. bags are usually supplied flat and are designed for high-speed packing in retail and food service environments.

By contrast, block bottom bags, which can be ordered here, feature a reinforced, flat base created by folding and gluing multiple layers of paper into a stable block shape. This construction enables the bag to stand upright independently, even when empty, giving it a more structured and refined appearance.

Sturdiness

S.O.S. bags are strong and reliable for everyday use, particularly when made from the right weight of paper. However, their base is designed for efficiency rather than maximum load resistance.

Block bottom bags generally offer greater stability and load-bearing capacity thanks to their reinforced base and sturdier structure. This makes them better suited to heavier products, premium goods or situations where the bag needs to keep its shape when being handled or displayed.

Customisability

S.O.S. bags can be adapted in terms of size, paper grade and handle integration if required. Their simple construction makes them cost-effective to produce in large volumes, supporting economical customisation for mass-market applications.

While block bottom bags are also customisable in terms of size and material, they often involve more complex manufacturing processes. While this can result in higher unit costs, particularly for smaller production runs, it also allows for more refined structural detailing.

Branding application

S.O.S. bags have large, uninterrupted side panels that are ideal for displaying printed logos, patterns and messages. Widely used in quick-service and retail environments, they are ideal for high-visibility, functional branding.

Block bottom bags, on the other hand, are often associated with premium branding. Their upright stance and clean lines make them stand out on the shelf and make printed designs appear more deliberate and polished. This format is often chosen for speciality food, coffee and gift packaging, where visual impact is important.

Overall, S.O.S. bags prioritise speed, efficiency and cost-effective customisation, whereas block bottom paper bags prioritise structural stability and an elevated brand presentation. The choice between the two depends on product weight, usage context and branding objectives, rather than one format being clearly superior to the other.