So if you have some old jars, how do you know their true age? If you have a Ball jar, you can date most of them just by looking at the logo. Every few years, the Ball Manufacturing Co changed the logo and if you compare yours to a reliable chart, you know how old it is.

What year is my Ball jar?

Not every jar has their manufacture date on the glass, but most have the patent date. However, this date has no relation to the year your jar was made. There will be a large number on the bottom of your jar. This is the mold number, and unfortunately also has no relation to the manufacture date.