The short answer is that the skin of the grapes gives the wine its color. When a grape is pressed the juice itself is clear or white. This is true of nearly every variety of grape. The pigments, or the substance present in plants (and animals) that gives it color, of grapes are in their skins. As the juice ferments the skins of the grapes shed pigments and give the wine its red color. The red colors vary from light red to ruby to maroon, garnet, almost black and nearly every shade in between.

If you press grapes and ferment the juice without the skins you end up with a white wine, even from red grapes. A white wine made from red grapes is called a blanc de noir. If you leave the skins in contact with the juice for a brief period of time the wine is only slightly colored and called a blush or rose’ (a term that has fallen out of use of late.)

Most red wines are of the varieties, Pinot Noir, Zinfandel, Merlot, Shiraz, Syrah, Cabernet Franc, Petite Sirah, Shiraz, Sangiovese, Malbec, Grenache, Pinot Noir, and Cabernet Sauvignon.

There are, however a minority of professional vintners, are employed in the production of wine by wine companies and wineries. Vintners coordinate with viticulturists, or those responsible for managing vineyards. Viticulturists monitor the plants for disease and pest attacks. They document the development of the fruit and control fertilization and irrigation. They maintain canopy management standards.They schedule the harvest and control the winter pruning of the vines. Professional vintners control the crushing of the fruit and the pressing process. They follow the juice through the processes of settling and fermentation, removal of the solid materials through filtering. They taste the wine and assess quality before the wine is stored and matured in casks or tanks. After maturation of the wine the professional vintner controls the bottling process and quality control once the bottling procedure is complete. Often the professional vintner has a degree in oenology or the science of wine due to the increasing accumulation and advancement of scientific knowledge in the industry.

Professional wine tasters follow traditions and utilize a system of methods that continue to evolve even after eight centuries. Many professional wine tasters are employed as sommeliers in fine restaurants and control all aspects of the acquisition, storage and serving of wine. Sommeliers also known as wine stewards have supplementary knowledge and information to assist management, educate wine waiters and assist customers of the restaurant.

Buyers for retailers have specialized knowledge of the wholesale and retail wine industry and are primarily responsible for obtaining quality wines at the lowest possible cost.

Thus wine amateurs and professionals shape and share a terminology used in the description of wines and their characteristic flavors and aromas.