When properly stored, Esbit solid fuel maintains its full functionality for many years.I'm not sure what Esbit means by "properly stored", but I had trouble with 5 year old Esbit tablets.
For my 2003, 500 mile PCT hike, I bought several dozen Esbit tablets. I didn't use most of them.
The tablets were stored in their original blister packs, inside Ziploc freezer bags, inside a sealed 5 gallon bucket, in a 55° F basement. Pretty good conditions, in my opinion!
In 2008, I pulled some of those 5 year old tablets out for a trip.
While cooking the first night's dinner:
- The tablet "popped" repeatedly, like popcorn.
- Each pop threw off small, flaming bits of tablet
I cooked meals successfully, but I watched each cooked meal carefully after that, to avoid burning nearby items.
At home, I tried some of the remaining tablets. More than half popped and splattered.
Throwing dozens of Esbit tablets in the garbage is a bad idea.
I piled the tablets up in a back yard covered fire pan, and burned the entire pile at once.
Lots of popping and splattering, safely contained within the mesh cover.
Now, I buy just the Esbit tablets needed, and buy fresh tablets if I have any doubt about the age of stored tablets.
I recommend replacing stored Esbit tablets every few years.