That's a very good question. I reached out to the University of Idaho for their guidelines in the development of new russet varieties to compared to the Russet Burbank in the potato processing area.

Initially, they look for things that affect the growing of potatoes such as yield, size profile and specific gravity (a high starch to water ratio that can result in a crispy fry strip) and things that Idaho growers want from a potato they plant including long term storability without accumulating a lot of sugars, low weight loss in storage, low susceptibility to disease.

For frozen French fries the consumer or customer guidelines can apply to your efforts to have fresh made in house French fry that many guests rave about. The attributes include looking at the color variation with the potato strips and within an order of fries, something called "sugar ends" which is where one end of a potato has a tendency to accumulate starch and sugar, this end fries up dark.

They also seek a sharp contrast between the interior of the potato fry strip and the exterior surface. This last measurement is interesting, a desirable trait is to have the insides taste like a fluffy mashed russet potato, a little dry and certainly not limp. that's when you can easily bend the potato strip without it breaking. Ideally the researcher or tester is looking for an interior that is not wet, and has a slightly hollow inside. The ideal exterior is one where the darkest part of the fry or the lightest is only one shade different from the majority of the color of the fry.

Here's another interesting test researchers or QA people do with the outside of the fry to check on crispness... They roll the fry strip between their thumb and a finger. Ideally, all four surfaces around the strip should have an edge.

You'll notice from the above, I didn't get into the taste of the French fry. Some of the taste is attributed to the potato, but even more important is the taste that comes from the oil. A chain that fries in peanut oil is different from a blend of oils is different from frying in olive oil. A fry that comes out of a freshly filtered fryer tastes different than a fry that is immersed in an oil that is about to break down from age or too much heat. A fry that is placed into the same oil as other fried foods such as onion rings or chicken or breaded shrimp will pick up those Flavors. Always best to have a dedicated fryer for the potatoes!