The Fourth of July is the biggest grilling holiday of the year. This creates a massive and highly predictable surge in demand for a very specific set of cookout foods. While grocery stores do their best to prepare, they often underestimate the demand. This leads to the inevitable and frustrating shortages of these nine key items in the days leading up to the holiday. The empty shelves are a direct result of the entire country trying to buy the same things at the same time.