Very often it is quite easy to confuse sweetness and fruitiness. Some customers will say "I’ve made this wine before and my last batch was ‘sweeter’ than usual".
What went wrong? Probably nothing. This is where the hydrometer reading comes into play. The only purpose of a hydrometer is to measure sugar content. So if one bottles the wine at 0.990 or so, it is dry. Otherwise,if stabilized at a higher level, say 1.000 or more, it will have some sesidual sweetness.
The qualities of the grapes will vary depending on yearly crops, rainfall, heat or coolness at night, etc. There is also a cross pollination effect which will influence the taste of the grapes, and therefore the wine.
When you get a pamphlet on wine varietals, you’ll notice the language used to describe taste: oaky, soft/bold tannins, vanilla, spice, strawberry, raspberry, plum, black cherry, coffee, and even tobacco! Those fruit flavours, while not being sweet, is what is referred to when one says the wine has a "fruity" taste to it.