Preheat oven to 350℉ or 180℃
Put garlic cloves onto a square of aluminum foil, drizzle with olive oil and wrap up in the foil.
Bake foil parcel for 30-45 minutes until the garlic is soft.
Chop the roasted garlic finely and set aside for later.
In a medium saucepan combine water, teriyaki sauce, pineapple juice, soy sauce, and brown sugar.
Stir over medium-high heat and bring to a boil.
Reduce to a simmer.
Add remaining ingredients and stir.
Add the chopped roasted garlic and stir it through.
Simmer for 35-45 minutes, stirring occasionally, until the mixture has reduced by half.
The resulting mixture should be thick and syrupy.
Allow to cool completely before using as a marinade.