Combine all the ingredients in a large saucepan, and bring to a near boil, stirring often.
As soon as it starts to bubble, reduce to medium-low. Stir often and watch it carefully so the sauce doesn't burn.
The cooking time will depend on the consistency you are looking to achieve. Expect it to cook down for 20-45 minutes. The sauce will thicken once it cools. I have made it thinner when I want to use it for a sauce or let it cook a little longer when I want to use it as a marinade.
Notes
For the pineapple liquid, combine chopped pineapple core with a splash of water and process in a high-powered blender until smooth.Please make sure you use reduced sodium soy sauce. I accidentally used the original stuff one time, and it turns out I made a flavorful salt lick.