[sandworm101]

Fluid flows/sticks more easily along the sharp seam than the rounded corners. So there is always a little bit close to that sharp focus point near your lips. You slurp/sip from that sharp point, drawing more fluid along the seam.

But, for exactly the same reasons, this thing is probably a pain to clean. Sharp corners and cleaning don't mix. That narrow seam will likely become caked in the dried residue of a hundred previous drinks. Even in an earth dishwasher, soap scum would be difficult to rinse out. I suspect these are not used many times.

[Terr_]

> But, for exactly the same reasons, this thing is probably a pain to clean.

I dunno, given the size I imagine a regular toothbrush could dislodge anything dried, and small sponge-on-a-stick could get it acceptably dry.

It's also worth asking what it might replace: On the ISS do they clean any drink-pouches, or are they all treated as disposable? I imagine that they become trash, since the next drink (or dehydrated drink-to-be) was probably already shipped in its own flattened pouch.

[vanderZwan]

> That narrow seam will likely become caked in the dried residue of a hundred previous drinks

On the other hand, without gravity there is convection, which means those corners probably don't dry out as quickly. If I'm right about that then rinsing left-over residue out with plain water is easier if you don't wait too long.