Thank you Shelley Sharpe and Taylor Robertson for your responses on residual sugar last week!
This week: Color
How does red wine achieve its color and what are some of the factors that can influence the color?
The color in red wine comes mostly from anthocyanins which are found in the skin of the grapes. The factors that can influence color include: varietal, duration of skin contact during maceration, exposure to oxygen, and age.
Exception: Teinturier grapes -- those that have anthocyanins in their flesh, making the flesh and juice red. Some of the wines made from these grapes can take on VERY deep red color, leading many to call them "black" wine.
A couple of others to mention:
Stem inclusion can stabilize color and change ph (other manipulations of ph to affect color are also available).
Color can come from Scott Labs and similar in a variety of forms.
Botryitis in white wine has a profound impact on color.
Co-fermentation of white and red grapes (Malvasia and Sangiovese, Viognier and Syrah) increases color stability.