Requesting comment from Rosa Labs on a double-open bag design for Soylent Powder.
Current Soylent powder tears open horizontally across the top. This exposes a plastic zipper leading to the bag’s contents. Once open, the bag is no longer sealed, and can be closed back up with a shorter shelf life. The zipper isn’t guaranteed closed in shipping, and so powder can be present outside the zipper once the bag is unsealed.
For a new design, I propose an internal and external opening with two systems to open.
Internally, the bag is separated into four or (currently) five compartments, representing 500kcal or the current 400kcal meal. Near the top, the internal bag is crimped and sealed together against one wall of the bag’s exterior. To facilitate this, the divisions extend upward to present an opening to fill; the crimp is exercised at the low point of the opening, and the higher point of this opening is torn off for recycling during the crimp.
Crimping leaves a one- or two-inch hood over the segregated compartments inside the bag. The zipper is outside this, and the bag’s outer seal is above that.
A plastic cord fused across the length of this hood can be pulled to tear all the way across, opening all compartments. A separate set of plastic cords each function to open one compartment.
No measuring scoops.
I can think of several designs that work to correct the obvious flaws, but they all get ridiculously complex. I haven’t optimized them down. The main flaw is that tearing this open doesn’t create a wide-mouth opening; it creates a slit. Construction is a matter of incremental crimping of the internal partitions to the interior of the existing bags, rather than crimping the two sides together alone; once such a process is developed, it’s cheap, but retooling is probably costly.
The simplest solution is to abandon the zipper and put an all-or-nothing opening on the bottom, and incremental tear-offs at the top.