Slice potatoes about ⅛” thick (a mandoline helps). Place in a large bowl, add
cold water to cover, and stir to release starch; drain. Repeat until water runs
clear.
Return potatoes to bowl; cover with ½ cup distilled white vinegar and 6 cups
water. Let sit at least 30 minutes or up to 2 hours. Drain; pat dry.
Fit a medium heavy pot with thermometer; pour in oil to measure 4”. Heat over
medium-high until thermometer registers 300°.
Working in 6 batches and returning oil to 300° between batches, fry potatoes,
turning occasionally to cook evenly, until golden brown and crisp (oil will have
quit bubbling), about 5 minutes per batch. Using a spider or slotted spoon,
transfer to a paper towel–lined wire rack. Season with salt.