Geology & Viticulture: An Earthcache EarthCache

This simple Earthcache brings you to Cayuga Lake’s oldest operating winery to examine how glacial activity contributes to shaping climates able to support viticulture.

This Earthcache has been placed with the owner’s permission. Kindly restrict your visit to business hours; Monday through Saturday from 10:30 to 5:00, Sundays 12:00 to 5:00.

Cayuga Lake Wine Trail is the oldest in the country. The Finger Lakes Region is home to over 100 wineries, hosts 9,000 acres of vineyards and crushes approximately 41,300 tons of grapes annually.

Rocks and Wine?

Geology is more than the just identifying rocks. Some of the oldest and most interesting applications of geology involve interactions between people and the noble grape, Vitis vinifera. Mounds of grape seeds have been found in prehistoric caves. Early on, humans recognized the relationship between the geology of an area and the success of various crops. Records of the ancient Egyptians and Greeks contain observations that certain regions seemed to produce better wine than others.

Viticulture in New York

Second only to California in wine production, New York has been producing wines since the earliest days of the US. The Finger Lakes are the main wine producing area in New York State. The Finger Lakes American Viticulture Area encompasses roughly 2.3 million acres and is named for the 11 Finger Lakes (from west to east: Conesus, Hemlock, Canadice, Honeoye, Canandaigua, Keuka, Seneca, Cayuga, Owasco, Skaneateles, and Otisco Lakes). Wine making in the Finger Lakes dates back to 1829 when William Botswick planted vines in his rectory garden in Hammonsport. This region contains the first winery in the United States.

It’s COLD here! Why are the Finger Lakes good for growing grapes?

Many factors affect the success of grape growing. Physical characteristics of a location, the geology, topography, soil and climate all influence grapes and the resulting wine. This concept is known as ‘terroir’, which means that all factors work together to create a region with particular wine characteristics. For the Finger Lakes, two important physical characteristics are immediately obvious, the sloping topography and the deep lakes. Both of these elements were created by glacial activity thousands of years ago when the advance and retreat of the glaciers carved out the Finger Lakes and landforms found here today.

The aspect and slope of where a vine is planted has an effect on the grapes. A 30 degree slope facing south can double the amount of sun the grapes receive. In a flat planting, the vines on either side of any given row will block sunlight to the rows next to it. But when the vines are on a hill, the sun can hit all the grapes hanging down on every row. A sloped hill also offers better drainage, and more air circulation. During the last ice age, these sloping hillsides along Cayuga Lake were carved and formed.

But what really makes viticulture possible at all here is the glacial lakes themselves. New York has a much colder climate than California, or France or Spain. Spain is considered a hot wine production region similar to the central valley of California. Even though New York is at about the same latitude as northern Spain, New York is much cooler and exhibits a continental rather than maritime climate. A continental climate is characterized by greater temperature extremes between summers and winters. Without the lakes, temperatures for growing wine grapes here would be too low. It is not the width or surface area of the lakes, but rather their depth, that has an influence on viticulture. The deep lakes, carved through glacial activity, serve as heat sinks. This moderates cold temperatures in the winter and delays bud-break in the spring until risks of frost have passed. The radiating effect of the lakes also extend the length of the growing season, but this is a very localized effect, so vineyards and wineries are clustered along the north/south orientations of the major lakes (Cayuga, Seneca and Keuka). Cayuga Lake is the longest and second deepest of the Finger Lakes at 38 miles long and 435 feet deep.

What are Growing Degree Days?

The Growing Degree Day (or Winkler Scale) works on the assumption that plants will grow at or above a specific minimum temperature. For grapes, it has been determined that growth begins at the mean temperature of 50 degrees Fahrenheit. Using simple math, one can figure out if an area will have enough warm days between April 1 and August 31 (growing season) to successfully grow grapes. Days in the growing season are assigned ‘Degree Days’ according to the amount that the day’s average temperature exceeds the minimum threshold for growth: one Degree Day is assigned per degree Fahrenheit over 50 degrees. All the day’s scores are then added up, for a total Accumulated Degree Days. This calculation allows you to evaluate one of the elements necessary to support viticulture. The chart below outlines some common wine making regions, their latitude, and their accumulated seasonal Degree Days.

Four areas in New York have enough growing Degree Days to support winemaking. These are the Erie Lakeshore, the Finger Lakes, the Hudson Valley and the tip of Long Island. The illustration below charts accumulated growing degree days for the state, with grape growing regions shown in pink.

• Take a photo of yourself with your GPS at the arched trellis on site with the lake in the background.
• Calculate the growing degrees your day contributed to the grapes here. Look up the temperature high and low on the day of your visit. Determine the mean temperature for the day. Subtract 50. (In the winter, it is likely that your day will subtract from the total growing degree days, and be a negative number).
• In your log, post your photo and your math.
• Send me an email with the answer to the following question: Name two geological properties of this site that support the growing of grapes and explain how they do so.