How do dried bilberries differ from fresh ones, and do they lose their substances when dried?

During drying, moisture is removed from the bilberries – the berry loses volume and weight, but the concentration of dry matter per unit of mass increases. Anthocyanins, the plant pigments that give bilberries their dark blue colour and have antioxidant activity, are generally stable at moderate drying temperatures and are retained in the dried product. Pectins (dietary fibre) also remain: they are not destroyed by drying, since they are structural components of the berry's cell walls.

What does decrease during drying is the vitamin C content: it is sensitive to heat and oxidation. So dried bilberries are not the best source of ascorbic acid, unlike fresh or frozen berries.

The practical conclusion: dried berries are convenient as a concentrated plant raw material for infusions and blends, and they are easier to store and use at any time of year. Fresh bilberries in season give more vitamin C, but dried ones keep the polyphenol profile and pectins – and that is what they are traditionally valued for in European herbal practice.

One portion according to the label is 2 tablespoons of berries per 200 ml of boiling water, so 50 g is enough for about 2–3 portions.