Common Bilberry or European Blueberry (L. Vaccinium myrtillus) is a deciduous sub-shrub or dwarf shrub that belongs to the genus of Vaccinum in the family of Ericaceae. Its Estonian name “mustikas” refers to its colour (must means black in Estonian), also to the fact that ripe berries smash easily and stain people’s hands and faces. Its berries are ripe by July-August. Common bilberry grows all over Estonia in damp forests, wood or bog edges, mostly preferring acid peat soil. European blueberry is a high-value berry plant. Its dark blue berries have pleasant sweet taste. They contain sugars (5–7%), pectic substances, organic acids (malic and citric acid 1%), tanning substances (7%) from the group of pyrocatechines. It is also rich in valuable vitamins: vitamin C, carotene, vitamin PP, vitamin B1 and B2. Its leaves contain tanning substances (up to 20%), arbutin (1.6%), the glycoside called myrtillin (1%), the glycoside called neomyrtillin, flavonoids and organic acids. Its berries are made into uncooked and cooked jam, compotes, jellies, marmalade, juice, wine, etc. Berries can also be preserved dried or in a bottle. The colourant found in European blueberry is a pH indicator. When the pH of its habitat decreases, the colourant will turn from red to blue. It is used as a food colour as it is completely safe and natural, for example for stamping meat.