Dr. Potato which uses more oil when frying, fresh cut or frozen fries?
You asked a very good question. The short answer is that the frozen fries will use less oil in your operation than the fresh fries.
Idaho® potatoes average 21% solids or starch and are 79% water. When the processor blanches the potatoes for frying they may do this with water first or oil or a combination. That takes out moisture and replaces some of the water that boils off with oil. The frozen fry strips come out of a conveyor belt, are air dried and frozen before being bagged and boxed and sent on to your distributor. These steps are extremely efficient. They measure the solids from each raw batch of potatoes and can adjust the temperatures for frying optimization, they can reclaim much of the oil during the various steps and accurately measure weights. They test the potatoes by sampling and finish frying. The steps are a lot more accurate than you can replicate in a unit.
For example, in a unit an eighteen-year-old kitchen worker might fill one basket 1/2 full and the next one 2/3rd's full. Given the same fryer oil temperature, one is going to have to cook longer, and in all likelihood will absorb more oil, than exact fry temperatures and potato quantities in an industrial operation. Are you blanching and finish frying or frying in one step? The one step process will also use more oil in the unit.