I just finished making some Blueberry wine, it was sweet, just how I like it, but the alcohol content was very low. I put in 2 lbs of sugar. I'm going to give it another go. Any hints or tips on increasing the alcohol content.
What's your recipe? What's your process? etc etc, we need much more info to help out. But in absolutely basic terms, to up the abv you need to add more fermentables (sugars) to the original mix or along the way.
If it was sweet, my guess is that it didn't ferment out all the way. What yeast did you use? All the wine yeasts I've use ferment down from dry to very dry.
I agree that it may have stalled early due to low temps or not enough nutrient. Please post recipe so as we can figure this out. If you have this batch bottled you might have ticking time bombs ready to color your basement a pretty color.