Unlike the common belief that a back or brown spot on your potato chips is a sign of spoilage, experts say that they are actually either bruises or the result of excess potato sugars darkening during frying.
This also means that such potatoes are still safe for consumption despite bearing such minor imperfections.
According to scientists, a potato with black/brown spots has faced stress which caused it to convert its starches into sugars. Such stress is typically caused by rough handling or the indignity of lying at the bottom of the potato heap.
Such impacts can lead to bruising on the potato’s surface or just beneath it. Similarly, storing a potato at temperatures that are too cold can cause infections and insult a potato’s sensitivities.
In all of these scenarios, strange colors may start to appear in the potato’s flesh which could also lead to an unsightly brown spot in your potato chip.
There is also a less discernible form of discoloration in potato chips and fries, one that can’t always be predicted merely by looking at a raw potato. That brings us back to potato stress.
Stressed potatoes breathe at a faster rate, which, along with other factors, causes the potato to turn more of its starches into quick-energy sugars. That sugar may be invisible in a raw potato but it turns brown when it’s fried.
Most importantly, it's a delightful find knowing that there are no safety concerns. The potatoes will still retain their nutritional qualities but you may notice a softer texture and an extra sweetness. Overall, there won't be any significant change in the flavor of the potato chips.