Like so many Canning 101 posts that have come before, this week’s post is prompted by a handful of emailed questions I’ve gotten recently. People have been writing to ask about the condensation droplets on the undersides of their mason jar lids. Is it safe, they wonder?
It is entirely normal to have a few drops of moisture on the underside of freshly processed mason jar lids. You experience condensation when warm, moist air is cooled. The cooling air doesn’t have the same capacity for water vapor as the warm air, so the water transforms back into its liquid state. It just makes sense to see some drops of liquid inside the jar.
It is not a sign that your jars are spoiling or that some water from the canning pot leaked into the finished product. Typically, the condensation will eventually reintegrate into the product. If it doesn’t, it’s still not a sign that it is spoiling. As long as the seal is still good and the product doesn’t look significantly altered, all is well.