When I open a simple juice carton I fail on opening. I always seem to waste some of the concentrated juice on the kitchen sink and I wonder – do I do it wrong or is it the package that does not have a useful design?
Cartons definitely need re-design. The case is being:
Material - Cartons are light in weight to take the load against Tin cans which takes little bit of load and pressure.
Load and Pressure - Cartons take pressure laterally and vertically, which pulls the juice out of it in rapid fashion. Lateral pressure comes in with your hand already placed on the carton walls at its center, and Vertical pressure comes in when the carton is teared upon, so as while the tearing ends, you naturally keep applying force to it laterally, as the juice comes out of the torn portion.
Solution towards this should be strengthen the material used or redesign taking the pressure fact into consideration.
Cartons as far as I seen are one with "tearable slot" as it is with tin cans, other way of cartons are one which are sealed and have or do not have "tearable slot", with tearable slots either at the top of the cartons or at the end of it - forming a triangle pattern.
Best way to address this problem is that the Cartons should have a firm wall at the center, as you even though apply pressure, it does not affect the liquid inside it.
Have a taller carton such as atleast 0.3-0.5% more than the carton's height to avoid the rush of liquid (here some extra investment is required for materials).
Redesign the tearable slot.
As you also practice along, the spill can be avoided if you had to hold the top portion of the carton without applying more pressure, need to keep it on a surface (such as you can avoid the full force).The edges of the carton are little firm than the center portion.
The problem is that the seal needs to be good enough to keep the juice inside, throughout its journey to your fridge. At the same time, the opening process needs to be easy enough to tear by hand. In many cases, this balance is not reached, because it is too hard to open.
The process of manually opening a juice carton involves holding tight and tearing ( or cutting ). It is quite an aggressive action. In the process of making this hole in the packaging, there is a likelihood of the package shaking, spilling the juice.
Most of the more advanced methods - as Liam indicated - remove the need to grip the carton so tightly. But, of course, they cost a bit more.
Poor design i'd say. I tend to cut off the corner, with an optional hole the other side to allow air to get in to stop the erratic pouring.
Alternatively, my mum used to have something similar to these (pictured below). That particular one is discontinued, but Amazon lists a few alternatives which look like they do the same job.
In the UK Tetrapak dominated supermarket shelves for liquid packaging, but increasingly I see plastic and screw top waxed cartons: http://youtu.be/2-p8YpR7rJc - No wonder !
They'd work much better if there were a tab with which to break the seal and pull the mouth open.