What happens to fries if the cooking oil is too dark?

When the cooking oil is too dark, it typically indicates that the oil has been used extensively or has begun to break down. This can lead to uneven cooking of the fries. The breakdown of oil can affect its heat distribution, resulting in some fries cooking more quickly while others may remain undercooked. Additionally, dark oil often absorbs and retains more unwanted flavors or burnt particles, further contributing to inconsistency in both texture and taste. Thus, the uneven heating and potential for off-flavors make it difficult for the fries to achieve a uniform, desirable result.