I oftentimes ship a sauce only sold in my area to family at different elevations. The problem is that the bottle it’s sold in isn’t very secure and many times it’ll break in transit and leak everywhere.
What should I look for when shopping for bottles/containers to use for shipping?
If it’s sauce, there probably isn’t much air. Space in the jar is a partial vacuum with some vapor from the sauce. Air in the container will let the sauce spoil.
You probably just need a heavier container.