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Color in grapes from different climates

I am in the process of studying for the Certified test and had a question on the color in grapes from different climates. I was reading my Deductive Tasting Method Workshop packet from the CMS and it has in the section, GEOGRAPHY IMPACT under deductive logic parameters for warmer and cooler climates, some contradiction with what The Science of Tasting info the Guild has. 

In the Workshop packet is has "Color is slightly darker for the grape variety" under the warmer climate section and "Color is pale for the grape variety" under the cooler climate section. In The Science of Tasting info from the Guild it says that this is a not true. It states that color (anthocyanins) is inhibited by heat and that cooler vintages can produce darker colored wines than warmer ones. 

Any of my awesome wine cohorts want to clear this up for me?!



  • In my experience, there are numerous factors involved and colour also depends on winemaking practices. I live near to the Willamette Valley so that is the region in which I am most familiar. The moderate 2008 vintage in the Willamette Valley produced darker coloured wines and more blue fruits (boysenberry, blueberry) because the berries were smaller, hence higher skin to juice ratio, than either an abundant hot vintage such as 2009/2012/2014 or a cool vintage such as 2007 or 2011. Colour and concentration in 2013 depended on whether you picked before, during or after the rains.
    Can you identify which Syrah is Northern Rhone vs South Australia by colour alone? I can't. I have seen high quality examples of both that are deep purple or less intensely hued. Personally speaking, I wouldn't worry too much about the intricacies of depth of colour in deductive tasting. Identify thin-skinned, medium, and thick-skinned grapes and let the quality of the fruit (just ripe, ripe, over ripe, dried) speak to you about the possible growing conditions.
    Here is a quote from a paper written by Dr. Bruce W. Zoecklein for the Wine/Enology Grape Chemistry Group at Virginia Tech: Anthocyanins, as a group, have an optimum temperature range of about 17 to 26°C, suggesting that berry color would be more difficult to achieve in extremely warm and extremely cool regions. Excessive berry exposure and excessive
    canopy shade can also impact the rate of berry maturity and, thus, color development. Excessive irrigation, too much nitrogen, calcium deficiency and Botrytis growth can negatively impact grape color.
  • Rhett,

    There is no black and white answer here, particularly with deductive tasting and assessing color. There are way too many factors that can affect color outcome. Tying only the climate to the color is a generalization, which I'm positive the Masters expanded upon in the workshop you attended. I'd imagine, however, they mentioned using color alone can lead you astray in conclusions. Use it as a base starting point in your deductive method, a small piece of the overall evidence if you will.

    For example, I was just in the Sierra Foothills last week, speaking with Ann Kraemer of Shake Ridge Ranch who has decades of experience between Napa and Amador. They don't focus on Cabernet in Amador much because although it is ripe by the numbers, the phenolic development isn't there. Amador has the same average temperatures as Calistoga/St. Helena, but a shorter growing season with immediate daily rises/drops in temperature, along with higher elevation. This is not a place you want to be exposing your clusters if you are at elevation - The highest vineyards are above 3,300 feet, and most vineyards here far eclipse the majority of Napa Valley. Yet, they're just as hot during the day. Sunlight and 90 degrees at elevation is going to feel more intense than sunlight and 90 degrees at sea level, for grapes or humans. 40 minutes or so west in Lodi they have a hard time achieving color in Cabernet and will blend in Petite Sirah. Drive another hour west to Napa and Petite Verdot is usually your blender for color.

    Vines start to shut down photosynthesis above mid-90s temperatures, meaning a warm climate can (not always) be counterproductive to anthocyanin (color) development in grapes. In cooler climates, you may expose the clusters to receive more sunlight to encourage photosynthesis (among many other reasons), particularly if you have a shorter growing season.

    Again, I don't think either is wrong. Generalizing color in warmer climates is a base to start from with the deductive method. Color hints at things that should be looked at more closely on the nose and palate. I would say you're better off assessing what that color means as you start to consider fruit condition, structure, oak usage, botrytis, youth/age of the wine, and more.

    Hopefully that helps, good luck!
  • A nifty tidbit I picked up from the CSW program dealing with anthocyanins: they are affected by acidity in the grape. The higher the acid, the more red the color in the glass will appear. The less acidity there is, the more blue and purple tones will start to show. The question of color is of course, not black and white as mentioned above. But this has definitely helped me in my tastings. Think Cahors next to Mendoza- yes there is a natural purple hint to Malbec, but side by side you can see a difference. Imagine some notoriously high acid reds- Nebbiolo, Sangiovese, Bourgogne Pinot- and you start to see that pattern of rusty red hue. Its not the whole picture, but for me its a great corner-piece of the puzzle tgat helps me frame it in. It triggers questions of vintage, eliminates certain varietals....Chris Bates has a fantastic 4 box chart that, in generalities, breaks reds down into Red/Purple and Opaque/Translucent. Really tokk my tasting up a few notches.