How long can I store the Dynacem in a dry place to have it still in good working condition?

You can store Dynacem in unopened bags 1 year from purchase day or longer.

After 1 year you feel no difference in field performance.

After 2 years it works slightly longer but it can still be difficult to notice the difference in performance on the jobsite.

After 3 years it breaks the same rock but it needs 2 or 3 days instead of 1 day (and may not work with reinforced concrete).

Opened bag will decay faster, but you can vacuum pack it to keep fresh for another 1 year.

You can vacuum pack unopened bags to keep fresh for 3 years (and probably longer).