Prepare your potatoes by peeling them and slicing them into fries. When they're not being handled, keep the potatoes submerged in lukewarm water to keep them from browning.
Add the cut potatoes, vinegar and salt to a large pot, then add enough water to cover them. Put a lid on the pot and bring the water to a boil. Depending on the size of your fries their cook times may vary between 10 and 20 minutes. Check if they are tender throughout to check for doneness.
Drain the fries and let them rest on a drying rack or kitchen towel for 5 - 10 minutes to let off steam.
Heat oil to to 204 degrees C or 400 degrees F in a fry pan with enough oil to cover a batch of fries. Fry the potatoes in batches small enough to prevent over crowding. Agitate the fries while they're in the oil to make sure they get an even fry. Take them out after just a minute or two.
When all the potatoes have had a turn in the fryer, let them cool completely, then put them in a plastic bag and suck out all the air (if possible) to prevent ice crystals from forming on the potatoes. Put the bag in the freezer overnight, or they can keep up to 3 months before you go through the final step.
Heat your fry pot of oil to 204 degrees C or 400 degrees F. Gently lower the fries into the oil, being careful of severe popping from ice crystals. Let them fry for a couple minutes and take them out when they have a nice golden color. Serve with whatever sauces you like. Try malt vinegar!
In case of a grease fire, turn off the stove and cover the pan with a metal lid or cookie sheet. You can also put a ton of baking soda on it to snuff it out. Don't move the pan and splash burning oil around your kitchen. If it's a big one you need to use a fire extinguisher. For the love of god, DON'T use water.
