Wash the peanuts very, very well in cold water. Place them in a large pot that will allow them to be covered with two inches of water.
Fill the gallon jug with tap water. Add one cup of kosher salt. Stir. The salt doesn't have to dissolve because it will when it cooks.
Keep mixing up the brine with the ratio of one gallon water to one cup of kosher salt until the top of the peanuts are covered with two inches of water.
Cover and bring to a boil. Keep covered.
As the peanuts boil, occasionally push down the top layer.
After an hour, start testing the peanuts. I say an hour just to be on the safe side because they probably won't be near done by then.
To test: scoop peanuts out of the boiling water. Blow on them until they're cool enough to handle. Crack open and pop the peanut, not the shell, into your pretty little mouth. Chew on the peanut. If they're not tender or salty enough, keep cooking and test every hour repeating the same procedure.
Keep adding water to the cooking vessel as needed. CAUTION: Do not add more brine, just add fresh tap water. As the brine cooks down, it become concentrated. The salt isn't leaving, it's still in the pot. You need more water, not more salt.
If they reach the right texture but aren't salty enough, take them off the heat and let them sit in the brine. Test for saltiness every 10 minutes until they get right. Once they reach the perfect stage, drain the brine. If you leave them sitting in the brine, they will continue getting saltier.
If you realize they've gotten too salty, don't panic. Drain them from the brine and cover with fresh water. The salt will be drawn out of the peanut into the fresh water. Keep testing until the peanuts get right for you.
To freeze, drain the brine and store the peanuts in resealable freezer bags. To eat, let them thaw.