Your food cost percentage (COGS / Revenue) should ideally be around 28-32% for food and 15-20% for coffee. If it's higher, you hold a leaky bucket.
Formula: (Beginning Inventory + Purchases - Ending Inventory) / Total Food Sales.
If your number is high, look for: theft, waste, unrecorded comps, or simply portion sizes that are too large. Adjust recipes or prices accordingly.