You've a very good point Faldage. Glass bottles are very expensive to ship because of the weight. I know that for 1L foam bath, it nearly doubles your freight costs because the glass bottles weigh more than the plastic bottles and you cannot double-stack the pallets in the trucks.

One of my manufacturers makes soup stocks. The tetra pak stocks are much more expensive to produce than canned stocks but people like them because they are more convenient. They are made with a spout so a reasealable if the whole litre is not used.