Lump charcoal does not expire in the way food does, but it can become difficult or impossible to light if it absorbs enough moisture. We get questions about storage fairly often, usually from customers who bought a large bundle and want to make sure the bags they are not using immediately will still be good in three months. The answer is simple, but there are a few specific things worth knowing.
Why moisture is the problem ¶
Charcoal is highly porous and absorbs water from the surrounding air. A bag of charcoal stored in a humid environment will gradually absorb enough moisture that the pieces become difficult to light and produce excessive smoke when they do catch. The charcoal is not ruined in any permanent sense. Dry it out and it will perform normally again. But preventing moisture absorption in the first place is easier than recovering from it.
The best storage setup ¶
A sealed bag in a dry garage or shed is the simplest and most effective storage method. Our kraft bags have a resealable top fold, and folding it down tightly after each use is enough to keep moisture out in most climates. If you live somewhere with high humidity, storing the sealed bag inside a plastic bin with a lid adds another layer of protection. The goal is to keep the charcoal away from ambient air, not to create a hermetically sealed environment.
What not to do ¶
Do not store charcoal in a metal can with a tight lid in a hot environment. Charcoal can off-gas slightly as it acclimates to temperature changes, and in a sealed metal container in a hot garage, pressure can build. It is not a dramatic safety risk, but it can deform the can and make it difficult to open. Also avoid storing charcoal directly on a concrete floor, which can wick moisture up through the bag. A wooden pallet or a shelf keeps the bag off the ground.
Recovering wet charcoal ¶
If a bag of charcoal gets wet, either from a leak or from being stored in a very humid space, spread the pieces out on a dry surface in direct sunlight for a day. The sun will drive off most of the absorbed moisture and the charcoal will perform normally again. This works even for charcoal that has been quite wet. The one exception is charcoal that has been submerged in water for an extended period, which can cause the pieces to fracture and crumble. That charcoal is harder to recover and may be better used as garden amendment.
Proper storage is especially worth thinking about if you order a 4-bag bundle for the summer. Keep the bags you are not using in a dry spot and they will be in good shape whenever you get to them.