Ideas / SnackFoodOpening
HOWTO: Open snack foods packaged in welded envelopes
Ensuring adequate tear velocity for optimal unwrapping of snack foods
Many snack foods, most notably crisps (chips), but also nuts and various other things, are sold in plastic or foil packets. These packets are made from rectangles of material, first welded into a cylinder (along the longitudinal seam), and then welded shut across both ends (the lower and upper closing seams respectively). The resulting packet is usually bulging and rectangular in appearance, with the first weld running down the center back, between the two closing welds.
There are two main desired final configurations for snack food wrapping:
Methods for transitioning between configurations
The envelope method is easy: pinch the packet at the junction between the longitudinal and upper closing seam, and pull. The upper closing seam tears apart entirely, leaving the top end entirely open. Retrieving contents manually, or decanting them into a separate container, is thus rendered trivial.
The sheet method is not quite so easy though. The most commonly adopted method is to pinch the packet at the junction between the longitudinal and upper closing seam, and pull, maintaining force until the seam is nearly completely opened, and then increasingly the force just at the end. This starts a tear in the side wall, and once that tear is started it is easy to continue it down to the lower closing seam, and then open that seam, resulting in a rectangular sheet perfect for allowing maximum access while keeping the contents protected from the underlying surface.
Novices often neglect to apply this extra force, leaving the side wall untorn. Starting a tear without a runup is a lot harder, and may require dental intervention or even tool use.
Alternative method of accomplishing the sheet
Some longitudinal seams can be easily opened once one of the closing seams has been opened. Try it and see. These packets require the least skill to open.
Advanced method for accomplishing the sheet
If a novice has failed to start the tear in the side wall, then with care it is possible to open the remaining closing seam, and apply the proper technique from there. However, with the other closing seam already open great care must be taken not to sacrifice the contents in the process.