Karen MacNeil, author of The Wine Bible, explains what gives wine its color:
Why is White Wine White and Red Wine Red?
While starting this section with the question above might seem almost too basic, over the years I’ve found that most people don’t get the answer quite right. It isn’t just “because of the skins.”
The juice of all grapes, red and white, is almost colorless (with a few rare exceptions). Thus, red skins alone do not make red wine red. The big difference between red wine and white wine is this: For red wine, the juice is fermented with the red grape skins. During fermentation, heat and alcohol are generated. Both are solvents that help leach out the reddish-purple color pigments from the skins, tinting the surrounding wine. In the absence of this heat and alcohol, “red” wine in a fermentation vessel would actually be a pinkish liquid with red skins floating around in it.
With white wine, the skins aren’t necessary to tint the juice (it’s already clear), plus the skins might add tannin, an undesirable element in white wine. So, in making white wine, the skins are quickly separated from the juice before the juice is fermented.
The Wine Bible
by Karen MacNeil
Like a lively course from an expert teacher, The Wine Bible grounds the reader deeply in the fundamentals while layering on informative asides, tips, amusing anecdotes, definitions, glossaries, photos, maps, labels, and recommended bottles. Karen MacNeil’s information comes directly through primary research; for this second edition she has tasted more than 10,000 wines and visited dozens of wine regions around the world. New to the book are wines of China, Japan, Mexico, and Slovenia. And through it all the reader becomes ever more informed—and, because of the author’s unique voice, always entertained.