Place fries in a pot and cover with 5 quarts of water and the 5 tablespoons of white vinegar. Bring to a boil and cook for 10 minutes. The fries should be cooked through but not falling apart. Remove them with a slotted spoon or spider onto a baking sheet lined with paper towels. Cool and dry the potatoes on the tray.

Once the potatoes are cool and dry, heat the oil in a deep fryer or Dutch oven. Heat until a thermometer gauge reads 395F (1st fry). Working in batches cook for 2 minutes (oil temperature will drop to 360F), agitating occasionally. Remove the fries and place on another baking sheet fitted with a paper-towel-lined rack. Let oil heat again to 395F. Repeat with the rest of the fries until all of them have been blanched in the oil for 2 minutes.

Let the fries cool and dry on the rack for 1 hour, and then freeze them. Store in a plastic bag or container until ready to give them the final fry. If eating on the same day, freeze at least for a few hours.