I have a package of Briess Golden Light DME, and I noticed on the back it had a date stamp of 130923 10:57, which I assume to mean it was produced on Sept. 23, 2013.
It got me wondering if DME actually had a shelf life. How long will a sealed package of DME remain useful as a brewing ingredient?
Stored cool, dry and out of sunlight, DME is good for 2+ years. The main issue is with it picking up moisture, when it then becomes clumpy. But once boiled it's still good and you can use it up to 5 years in small quantities (say 1-2lb/0.5-1kg in a 5 gallon batch.)
From the first item in the search results for "briess dme shelf life": Briess "Product Information & Typical Analysis" sheet for a similar DME [PDF Warning]
STORAGE AND SHELF LIFE
Store in a cool, dry location.
Unopened bags best if used within 24 months from date of manufacture.
