I was just in Denver, restaurant hopping and I noticed the fries at several were shoestring cuts and very dark. They were crisp and delicious, but seemed overcooked to me. A couple of places said they used Idaho potatoes, what is going on?A:
First off, I am guessing that they were not frozen French fries. Potato processors do such a great job on making the fries fry up crispy and light colored. McDonald’s set the standard for light colored shoe string fries when working with the J.R. Simplot company back in the late fifties when, on a handshake, Ray Kroc agreed to have them supply the frozen spuds system wide. McDonald's sources its potatoes in the USA from Simplot, Lamb Weston and McCain Foods and has strict guidelines for consistency.
With fresh cut fries, the first thing I try and find out is how cold the potatoes have been stored. Below 40 degrees F the starch in the potato starts to turn to sugar. Elsewhere on the Dr. Potato posts are tips on how to re-condition the potatoes to convert back some of the sugar to starch. Basically they need to be left out at a warmer temp. That's why you see some gourmet burger places, like Five Guys, put the potato bags on display in the dining area. It's more than just show!
New crop potatoes (typically occurring in September to November) may fry up dark. One step an operator can take is to place the cut strips of potatoes in water, rinsing till it runs clear and rids the outer surfaces of any excess sugars. Another step is to blanch or precook the potatoes at a lower temp for a little longer. This helps partially cook the potatoes, cooling them off changes the cell structure on the outside of each strip and then finish frying makes a crisper fry.
Finally, potatoes with lower starch or solids are more likely to fry up dark.