Who Has What?

This is not just the title of my preschool-aged kids current favorite book (let’s not go there), but also an interesting field of viticulture called ampelography, basically, a way to identify a grapevine variety at all stages of growth and development. The U.C. Davis professor who trained me (and thousands of others) in this field is Dr. Andy Walker, a passionate scientist with a lot of great stories about the pioneers of Californian grape and wine research.

To show some ampelography in action, I took some pictures of our merlot, cabernet sauvignon and cabernet franc vines, three grape varieties that are very similar in how they look. In the springtime, ampelography is all about shoot tip color and texture (later in the year, differences in leaf shape, berry and cluster shape, etc, become more apparent, but early in the season those differences are difficult to impossible to see).

The diagram here shows some of the areas that you need to look at when trying to identify a vine. Differences can be found in the color of the growing shoot tip, leaf margin, tendril (mainly the one right below the growing shoot tip), and surface of the unfurled (fully opened-up) leaves just below the shoot tip, as well as the overall downiness (fuzziness) of the youngest leaves and the growing shoot tip.

Merlot, on one extreme of the spectrum, has a very white, downy growing tips and upper leaves, both with red margins, tendrils that tend to be green (but can be streaked with a bit of red when they start to emerge), and unfurled leaves that are whitish and slightly downy with just a bit of a coppery tinge. Cabernet sauvignon, more in the middle, has white, downy growing shoot tips and upper leaves, both with crimson red on the margins. Tendrils that tend to be red and the margins and even some of the leaf surface become reddish/coppery on the lower unfurled leaves, much more pigmented than the merlot leaves.  Cabernet franc, at the other end of the spectrum, has upper leaves that are much less white and less downy, leaf margins that are more copper than red, and tendrils and unfurled leaves that have a distinct copper color.

MERLOT

CABERNET SAUVIGNON

    CABERNET FRANC

If you are interested in learning more about ampelography, Pierre Galet has written a nice guide called “Grape Varieties” that covers a lot of the most popular wine grapes and also discusses where in the world each is planted and the typical qualities of the wines produced.

- Sally Johnson, winemaker