Why can bilberry infusions taste overly tart?

Expanded Explanation

Bilberry infusions can taste overly tart because the fruit naturally has bright acidity and a more concentrated wild berry flavor than cultivated blueberries. When the berries are very ripe, this acidity is balanced by sweetness, but underripe or very sharp berries can push the liqueur toward a sour profile.

Alcohol can make tartness feel more direct, especially before sugar is added. If the infusion is tasted unsweetened, the acidity may seem stronger than it will in the finished liqueur. Lemon juice, citrus peel, blackcurrant, or other acidic ingredients can also increase the sharpness.

The best solution is controlled sweetening after straining. Honey, white sugar syrup, cane sugar, or a small amount of vanilla can soften tart edges. Do not add too much sweetener at once. Build balance gradually, then rest the liqueur for at least one or two weeks so acidity, alcohol, and sweetness can integrate.