Why do winegrowers and winemakers-especially Pinot growers-harp on about how cold their vineyard is compared to others? Is this a male ego thing? “Yeah, well I picked 2 weeks later than you, bucko, so I am cooler than you,” (perhaps not, eh?) But that’s not why it matters. It matters for a variety of biological reasons that I, the only one at Peay Vineyards without a degree in Enology and Viticulture, will describe. Vanessa and Nick gave me the nod that what I am saying is true, in general. There are many factors not captured in the explanation below. So take this as illustrative and not the gospel.

Remember graphing algebraic equations? The white sheets of paper with X and Y axes across the front that stared you down in 7th grade? So, imagine one of those graphs. Along the X axis is Time and Phenolic Development. You hear a lot about this last expression in wine journals. Put generally, phenolic development is the accumulation of phenol compounds in the skins of grapes that affect color, tannins (astringency), bitterness and other not yet scientifically well-defined flavor components. Along the Y axis you have Sugar level and Acid level. The slopes of the Sugar and Acid lines are correlated to heat as measured in Degree Days. ¹

In areas with more degree days (read: hotter), sugar levels rise faster and acid levels fall faster ²; thus the slopes of the lines are steeper. A third line on the graph, phenolic development, is not well-correlated to heat (i.e. if it is warmer, the grapes do not develop more phenols faster; heat does not affect the slope of the line). Instead, development is based on time. The longer the fruit is on the vine (the oft-blustered claim of hang time), the more phenols accumulate in the skins. The more phenols in the skins, the more color, evolved tannins (not just amount but degree of ripeness and improved perception on the tongue), and potentially, more flavor compounds are available for extraction.

Among other considerations, winemakers pick when the acid and sugar levels reach their optimal levels. For acid, the winemaker wants a level that provides structure so the wine will have some vitality and will not wash out on the palate (finished pH of 3.3-3.7). Alcohol contributes weight and structure to a wine but when there is too much, the wine is disjointed and unpleasant, especially with food. Let’s just say ideal alcohol levels range from 12.5%-14.5%. But since phenolic development is based on time, if sugar and acid levels hit their sweet spots in a short period of time (closer in on the X axis) due to greater heat, then the grapes will lack the flavors, tannins and color necessary to make a complex, developed wine. However, once the grapes reach their optimal acid and alcohol level, you cannot let the fruit hang on the vine to gain phenolic ripeness or the acid and sugar levels will continue to change, and the resulting wine will be out of balance. In a perfect world, all three lines reach their optimal points simultaneously far out on the X axis, right before the season ends and rains or very cold weather commences. Certain grape varieties need more heat to reach ideal levels (Cabernet Sauvignon, eg.) and, as a result, the “right” region for them is a relatively warm climate (Region 3). But Pinot noir (a quick ripener) is usually, or should be, grown in Region 1 or 2 to achieve its greatest expression.

What region is Peay Vineyards in, you ask? We are in Region 1; on the edge of where we can get enough sugar to develop and acid levels to drop so we achieve balance in our wines. In 2005 we had fewer degree days than Champagne. Is that good? Well, we think it results in more developed, complex wines. It certainly allows for more vineyard expression since when we pick we have considerable phenolic development and do not struggle with overripe flavors.

And what of Syrah? Well, as long as you have enough growing season to reach levels of ideal sugar and acid, then the cooler the site the better, right? Syrah certainly expresses different characteristics depending on which region it is grown in. In hot climates, there is often a softness from low acid with an emphasis on fruitiness, you might even say it results in a Syrah with “gobs of fruit.” In those climates, winemakers often wait for more phenolic development in the grapes and pick overripe and “adjust” alcohol or acid in the winery. In cooler climates, flavors of leather, black pepper, and meatiness are prevalent and there is often lively acidity. Think of wines from Côte Rôtie or Hermitage. Since our vineyard is in a cool region, we also experience these qualities. But since we have a longer growing season than the Rhône – we pick in late October as there is little rain – we often have more fruit development in our Syrah. Perhaps it is the best of both worlds? But I may be biased. “Hey, mine is…” Nah, that ol’ saw is tiresome.

1. A degree day is a measurement of the number of heat units created in that region that day. To calculate this, you take the daily minimum and maximum temperature, divide by 2 to get the average temperature and subtract the minimum threshold of 50 degrees to get heat units for the day. You add up all the daily heat units for the year and you get the number of degree days for that region (or vineyard.) Scientists have mapped out the U.S. in 5 bands ranging from coldest, Level 1, to hottest, Level 5.

2. More precisely, grapes swell with water which dilutes the level of acid in the grapes. In a warm climate-an area with more degree days-this happens more quickly so the acid line’s slope is steeper.