We wondered if we could save partially used coals and later reignite them for a future round of grilling.
With quick-cooking grilling recipes, like our Ultimate Charcoal-Grilled Steaks, we often end up with a fair amount of coals that are only partially used by the end of cooking. In the name of frugality, we wondered, if we immediately extinguished the coals by cutting off the air supply (the best way to do this is to dump them into a small, metal lidded container such as a garbage can), could we then save them to reignite in a future round of grilling?
We discovered that the answer is yes, with one caveat. Trying to light a chimney starter filled entirely with used coals was a nonstarter—these smaller coals nestled tightly together, greatly restricting airflow and delaying or even preventing the coals from igniting. However, we found that it does work to replace up to half of the fresh coals called for in a recipe with used coals. Before you get started, make sure to place your previously used, cooled briquettes in the charcoal chimney and shake and rap it over the trash to dislodge ash, which would impede the coals from properly igniting. To maximize airflow, be sure to place the fresh coals in the chimney first and top them with the used coals.