An unripe pineapple has too much acidity – too acidic.
An over-ripe pineapple has too much sweetness.
A perfect pineapple has a balance between acidity and sweetness. It is easy on the palette and easy to enjoy the succulent flavors.
Ultra light roast coffees are like unripe pineapples. The starches have not yet heated up enough in the green bean to break down into simple sugars (pyrolysis), so the brew is over-bright with too little sweet flavor to balance it. It is, in fact, unripe.