Vines grow in soil. The roots reach deep and bring in water and nutrients. Soil matters, but how much, and is there a best soil type for Chardonnay? Are there particular flavours and aromas that can be associated with different soil types? This School of Cool seminar at the i4C, has set out to discuss, but not necessarily definitively answer these questions. We had a guest speaker, Dr. Paul Anamosa, a soil scientist, give us his opinion, followed by a panel of 5 winery principals, to discuss their wines, and other’s wines from around the world, as it relates to soil.
- Paul Anamosa, Vineyard Soil Technologies (California)
- Stefan Tscheppe, General Manager Weingut Esterhazy (Austria)
- Gonzalo Perez, Winemaker Cremaschi Furlotti (Chile)
- Paul Berger, Winery Owner & Winemaker, Berger-Rive (Burgundy, France)
- Thomas Bachelder, Winery Owner & Winemaker Bachelder (Oregon, Burgundy and Ontario)
- Shiraz Mottiar, Winemaker Malivoire Wine Co. (Ontario)
What Does Dr. Paul Anamosa Say as a Soil Scientist?
Dr. Paul Anamosa is the owner of Vineyard Soil Technologies, a California-based viticultural consulting company, specializing in soil analysis and land evaluation for wine grape production, vineyard design, grapevine performance, and mineral nutritional disorders.
What does soil provide to wines?
What does vineyard management have to do it with?
What does wine making have to do with it?
Dr. Anamosa started off by showing us a diagram with what he views as the major and minor controls affecting grape flavours and aromas. According to Dr. Anamosa, climate & soils, which are on the outside ring of the diagram have the most impact. You can’t grow Chardonnay in areas with too poor climate or soil, for example Northern Manitoba.
The more fixed aspects affecting the grape are depicted closer to the centre of the diagram. Variety, trellis and rootstock & spacing more important once the vines are planted. You can change some aspect of the soil by adding lime and you can change climate a bit by vine orientation and lateral pulling. But management: fertigation, irrigation, pest management and canopy management are ongoing weekly management tasks and in Dr. Anamosa’s opinion has as much impact on quality of grapes as does soil.
Soil contributes nutrients, water, and anchorage to roots to the ground. Plants get nutrients from soil, water and the air. Nitrogen, Phosphorus, Calcium, Magnesium, Iron, Boron, Copper, Manganese, and Zinc are needed by plants. Some of the nutrients can come from the soil through the roots, like Nitrogen, while others, like Zinc and Copper are better sprayed on the vines’ leaves as the soil makes them less available (but it is not natural).
The structure of a plant also determines which nutrients and other chemicals can get inside. There are two parts to the plants cell structure: phospholipid membrane inside and the cell wall (the lattice structure) on the outside. The membrane is the guardian of what gets into the vines. Some lipids are susceptible to some pesticides. Eucalyptus tree oil from wind gets into the vine phospholipid membrane. (MyWinePal note, I have tasted Eucalyptus from some Australian wines, where there is a large concentration of eucalyptus trees).
The Kaolinite molecule, a clay mineral, is the smallest clay particle and is very common in soil. But this mineral, even though it is the smallest particle, is too big to get inside vine roots. So can we taste soil in wine?
What are the Nutrient Impacts on Grapes?
According to Dr. Anamosa, the following are nutrient impacts from the minerals:
- High soil nitrogen causes vegetative growth and thus more shade on the clusters.
- Deficiencies in Boron and Zinc will cause poor berry set and possibly earlier brix accumulation.
- Easy access to water causes vegetative growth and thus more shade on the clusters as well as higher risk to fungal disease.
- Excessive water stress will cause basal leaf loss, low berry set, smaller berries.
- High juice potassium > 2000 ppm in the grape leads to the berry pumping out hydrogen so the pH of the juice goes higher. The winemaker has to lower the pH by adding tartaric acid.
- High calcium can strengthen the cell wall and make berry skins thicker, making the grape crisp and chewy.
- Low soil nitrogen, you can cause low Yeast Assailable Nitrogen (YAN) which affects yeast during the fermentation process. According to Wikipedia, YAN is “…the combination of Free Amino Nitrogen (FAN), ammonia (NH3) and ammonium (NH4+) that is available for the wine yeast Saccharomyces cerevisiae to use during fermentation. Outside of the fermentable sugars glucose and fructose, nitrogen is the most important nutrient needed to carry out a successful fermentation that doesn’t end prior to the intended point of dryness or sees the development of off-odors and related wine faults…”.(https://en.wikipedia.org/wiki/Yeast_assimilable_nitrogen) Winemakers want a higher YAN, and may need to add diammonium phosphate in the wine making process, or nitrogen in the soil.
How Do These Factors Impact Chardonnay?
Dr. Anamosa quoted 2 different people in the wine industry. According to Daniel Roberts, viticultural consultant in Sonoma, the biggest impact on flavour of chardonnay is clone, water management and winemaker wizardry. David Ramey from Ramey Cellars in Sonoma says clone, balance of malate, tartrate, pH less than 3.6 and winemaker wizardry. Dr. Anamosa noted that lots of winemakers want to blame the soil, but researchers say that the winemaker has a large contribution. According to Marcus Keller from WA State, in his book “The Science of the Grapevines: Anatomy and Physiology”, the apparent impact of flavour components in wines can be influenced primarily by water management, which affects canopy, canopy size, shade, berry size, and structure within the berry.
There is a complex interaction of soil, light, water, and nutrition affecting grapes. Is this interaction to complex to quantify? Out of the myriad of things going on, can a correlation to soil be made? Wine writers describe wine flavours and aromas, but are we using the same language to describe the same thing? Are we tasting the wine and using the same term? Dr. Anamosa pointed out that Flavour and Aroma wheels have tried to provide a common lexicon that we can use. These wheels provide us with similes, e.g. this wine smells like apples. (It does help people build their capability to describe wine flavours and aromas in my opinion, but you first need to know what something smells or tastes like. What does quince taste like for example?)
So you can see from the above information, there are many factors that can affect grape flavour and aroma. Minerals are important; climate is important; water management is important; canopy management is important; and winemaker hand is important.
Guessing Soil Type by Blind Wine Tasting
From a wine’s flavours and aromas, can we correctly guess soil type? That was the next part of this seminar. We were presented with 10 glasses of wines, without knowing where they were made, or soil type. As you may surmise, there was not agreement in the soil type guesses for each wine, but in some cases, there was a definite majority that guessed a particular soil type correctly. Five of the wines were a clay-based soil, while the others were limestone, volcanic, glacial till, or alluvial.
The 10 wines and their soil types:
- WINE 1: GLACIAL TILL MIX, Lightfoot & Wolfville Vineyards 2014 Ancienne Chardonnay, Nova Scotia
- WINE 2: DOLOMITIC LIMESTONE & CLAY, Malivoire 2014 Mottiar Vineyard Chardonnay, Niagara
- WINE 3: LIMESTONE, Eszterházy 2015 Chardonnay Leithaberg, Austria
- WINE 4: CLAY LOAM, Creekside 2015 Queenston Road Vineyard Chardonnay, Niagara
- WINE 5: CLAY LIMESTONE, Manoir de Mercey 2015 Bourgogne Hautes Côtes de Beaune ‘Clos des Dames’, Burgundy, France
- WINE 6: SANDY LOAM, Adamo Estate 2014 Oaked Chardonnay, Willms’ Vineyard, Niagara-on-the-Lake
- WINE 7: VOLCANIC, ALLUVIAL, Cremaschi Furlotti 2015 Single Vineyard Chardonnay, Chile
- WINE 8: MARINE SEDIMENTS, Bachelder 2013 Chardonnay Johnson Vineyard, Oregon
- WINE 9: HEAVY CLAY LOAM, Southbrook 2013 Poetica Chardonnay, Niagara
- WINE 10: CLAY LOAM, Inniskillin 2014 Montague Vineyard, Niagara-on-the-Lake
One comment from Mr. Paul Berger from Burgundy, France made was describe their soil as a mix of mostly clay with some limestone. He noted that clay provides creaminess to the Chardonnay, while limestone provides, tension, minerality and freshness. I did make tasting notes for each wine and rated them. The wines that I enjoyed the most were WINES: 3, 8, 9, and 10, which are from SOILS: LIMESTONE, MARINE SEDIMENTS, HEAVY CLAY LOAM, and CLAY LOAM respectively. Maybe I prefer Chardonnay produced from clay soils? I will have to investigate this further on my own. To keep this article to a reasonable length, I will post my detailed tasting notes for these wines in a separate article. I hope you enjoyed reading about soils and the factors surrounding soils that can affect grapes. There is certainly much to consider.