Category Archives: soil

Aug 29 NO comments
agriculture, anthocyanins, Australia, Cabernet Sauvignon, ecology, economics, enology, fermentation, GPS, grapes, phenolics, prices, remote sensing, research, soil, Viticulture, wine chemistry, wine quality

Selective Harvesting: Is It Right For Everyone?



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When it comes to selective harvesting methods in the vineyard, there is an assumption that these methods may not be economically feasible for large quantity-producing wineries, as selective harvesting almost always requires more time, effort, and man-hours in executing.  Past research has found that the yield and quality of grapes is highly variable in the vineyard, which gives opportunity for winegrowers to better manage their resources and harvest practices for the desired quality of wine produced.

What is “Selective Harvesting”?

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Selective harvesting is defined as the split picking of fruit according to their yield and quality, in order to monopolize on a specific quality level in the grapes, and ultimately, finished wine.  This is sometimes achieved by sorting the grapes in the field into different bins depending on quality criteria, or by harvesting different sections of the vineyard at different times, again depending on quality criteria.  Studies have shown that grapes harvested from different portions of a vineyard may have significant chemical or sensory characteristics, which are often due to variations in the land and soil underneath the vineyard.

Selective harvesting may be problematic at times, as sometimes a winery may only have access to a single crusher or a minimum tank size of 75 tons, which can make separating grapes into two bins at harvest an issue, as well as filling a single tank with enough juice from a smaller selective harvest.  One study demonstrated that a 3 hectare low-yielding vineyard could not produce enough grapes to fill a fermentation tank with juice, which may make selective harvesting of smaller areas difficult when only certain sized tanks are available for use.

Perceptions of Selective Harvesting in Australia

In general, Australian wineries have the view that selective harvesting is only appropriate for small boutique wineries, or very large wineries that have access to a wide variety of equipment.  Those wineries in Australia’s inland warm irrigated region, according to the authors of the study presented to you today, are under the assumption that selective harvesting is not within reach.  It is because of this assumption that Bramley et al, 2011 sought to examine this assumption more closely, and to either support or refute the idea using field experimentation and economic analysis.

How did they do it?

The vineyard for this study was a Cabernet Sauvignon vineyard, planted in 1994, and located at the Deakin Estate in the Murray Valley of northwest Victoria, Australia.  Plant vigor and grape yield was calculated using remotely sensed digital multispectral video imagery, as well by using mechanical harvesters with GPS and Farmscan equipment.  Zones within the vineyard were characterized by being either high-yielding or low-yielding based on information gathered by the aforementioned methods.  After determining the yield would be too low for the fermentation tanks at the low-yield site, another low-yield site (harboring grapes with very similar characteristics as the grapes from the original low-yield site) from a Cabernet Sauvignon vineyard at Deakin Estate was also included in order to obtain the minimum yield necessary to fill the fermentation tanks available.

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Grapes were monitored throughout the growing season, and were harvested at 24 oBrix.  12 random bunches were collected from each zone in order to measure bunch weight, mean berry weight, juice Brix, pH, titratable acidity, anthocyanins (color), and phenolics.  Wines were created from bow low-yield zones and the high-yield zones in small-lot winemaking methods and also at the commercial scale.  For small-lot winemaking, 200kg of grapes were harvested then subsampled into three 50kg batches, and malolactic fermentation was not allowed to occur.  Commerical wines were made in 75 ton fermentation tanks which were filled for high-yield zone wines and filled only to 51 tons for the low-yield zone wines.  Malolactic fermentation was allowed to proceed for the commercial wines.  Standard winemaking procedures were used for all wines.

Experimental wines underwent a sensory analysis by 25 untrained panelists and Compusense Five (a sensory software tool).  For each comparison, the first sample presented was the reference sample, which was followed by two other samples, one of which was the same as the reference sample.  Panelists were asked to smell and taste the samples and to identify which sample was the same as the reference sample and were asked to provide the reason for their choice.

What did they find?

  • First and foremost, the authors noted a strong similarity between the remotely sensed data and the data collected from the GPS located on the harvesting machinery.  This provides evidence that the zones were actually separated properly into low-yield and high-yield zones. 


  • Wines created from the low-yield zone and wines created from a mix of low-yield zones were not significantly different, indicating that it was appropriate to mix the two low-yield sites without lowering the overall quality of the wine.


  • The wines from the high-yield zone tended to be more acidic and astringent than the wines from the low-yield zone.



  • When wines were made commercially, there was a significant different between wines made from high-yield zone grapes and wines made from low-yield zone grapes.  The low-yield zone grapes tended to be fuller bodied and less astringent, and with a fruitier aroma than the high-yield zone grapes.


  • Bunches from the high-yield zone were larger than those from the low-yield zone.  However, anthocyanin and phenolic concentrations were higher in wines made from low-yield zone grapes compared with high-yield zone grapes.  This result suggests greater wine quality in low-yield zone wines.


What do these results mean?

First, the results show that there are significant differences in yield and grape quality throughout different sections of a vineyard, which supports the need for purposeful zone delineation via posts, wires, or other means to separating sections of the vineyard.  Taking this one step further, another important result from the study is that if using remotely sensed data, it should be confirmed via ground-truthing (i.e. collecting information on the ground) to be certain the vineyard is being properly delineated.

The authors note that selective harvesting gives the winemaker greater control over the final blend of the wine, and ultimately the overall quality.  What many Australian winemakers are concerned about is the overall effect of cost when implementing such a strategy.  Even after taking in the harvest cost, the cost of small-lot winemaking, the harvest cost related to differing yield sizes, and total retail values (less expensive versus high-end prices), the researchers found that there was a total net benefit to a selective harvesting strategy.  See the table below (Table 2 from Bramley et al, 2011) for exact costs and benefits calculated.
Table 2 from Bramley et al, 2011

What about those vineyards that don’t make wine themselves?

There are many vineyards in Australia (and other places of the world, for that matter) that grow grapes to sell to other wineries, and not to make wine themselves.  Thereby, they do not have the added revenue of wine sold to add into the cost-benefit equation.  The authors were well aware of this fact, and performed a similar economic analysis to the one just mentioned, except leaving out the cost of winemaking and any potential wine revenue.  Even after taking these things into consideration, the researchers found that selective harvesting results in an increase in net financial benefit by more than 9% (in this particular example).  See the table below (Table 3 from Bramley et al, 2011) for exact costs and benefits calculated.

Table 3 from Bramley et al, 2011

Conclusions

The results of this study indicate that the notion that selective harvesting is only feasible for larger wineries with a variety of equipment sizes or small boutique wineries is incorrect, and that selecting harvesting may be financially feasible and beneficial for those wineries who undertake more large-scale production methods (at least in warm inland irrigated regions of Australia).  It is important to note that in order to maximize the benefit of selective harvesting, detailed analysis of the vineyard to delineate yield and quality zones must be confirmed using both remote sensing data and data collected directly from the ground.

Overall, I found this study interesting in that it showed that selective harvesting may be an option for all types of wineries, and is not limited to only those wineries with a greater variety of equipment or small boutique wineries.  One needs to remember, however, that this study occurred in a very specific wine region (warm inland irrigated region of Australia), the results of which may or may not be extrapolated to all wine regions around the world.  More research would need to be done to determine if this sort of harvest method is appropriate for wineries in any given wine region.

What do you all think of this topic?  If you’re curious to know more details about the methods or results of the study, please feel free to ask and I’ll see what I can find!

Please feel free to leave your comments below!

Reference:

Bramley, R.G.V., Ouzman, J., and Thornton, C. 2011. Selective harvesting is a feasible and profitable strategy even when grape and wine production is geared toward large fermentation volumes. Australian Journal of Grape and Wine Research 17: 298-305.

DOI: 10.1111/j.1755-0238.2011.00151.x
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!
May 24 NO comments
agriculture, Chardonnay, chemistry, cover crops, ecology, environment, grapes, organic, plants, research, soil, soil erosion, Viticulture

The Effect of Long-Term Organic Compost Treatment On Soil and Grape Quality



Composting has been shown to increase soil quality by increasing organic matter and altering concentrations of nitrogen and phosphorous, as well as changing bulk density, porosity, and water holding capacity.  These changes could be beneficial for soil conservation, particularly in soils that are degraded or damaged and prone to erosion.  Not only is composting beneficial for the soil, but the changes to the soil could also be very beneficial for those plants and animals/insects growing in it.

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In terms of wine, it is been well documented that soil characteristics play a role in the quality of the wine produced from the grapes growing in that soil.  Though the chemical composition of grapes is well known, very few studies have examined the effects of composting on this composition.  Therefore, the goal of the short study presented today was to examine the long-term effects of composting on the yield and quality of Chardonnay grapes grown in a Tuscan vineyard.

Methods

The experimental vineyard was located in Cesa (Italy) inside the Centro Sperimentale per l’Agricoltura e l’Innovazione – ARISA Toscana.  The climate is Mediterranean (dry subhumid) with an annual rainfall of 550mm.  Autumn is prone to heavy rainfall events, which can cause problems with soil erosion and soil nutrient loss.  The experimental vineyard belonged to the DOC region of Bianco Vergine di Valdichiana, with a slight slope of 2.5% and a NE exposure.  Soil type was a loamy soil rich in alluvial sediments with limited water reserve.

The grapes used for this experiment were Chardonnay (Entav-Inra 95 clone) vines that were grafted on SO4 in 1996 and cordon trained with a density of 2700 plants/ha.  Vineyard management practices included maintaining soil covered by grass between rows.  In 2001, the vineyard was split into three experimental plots and treated with different fertilization types.  Treatments were applied with the following:

  •         Treatment A: Control treatment with chemical fertilization (50kg N/hectare/year, 30kg P/hectare/year, 70kg K/hectare/year)
  •        Treatment B: Organic compost treatment with 15tons/hectare/year applied.
  •       Treatment C: Organic compost plus chemical fertilizer treatment with 15tons/hectare/year applied for the compost, and 25kg N/hectare/year, 15kg P/hectare/year, and 35kg K/hectare/year applied for the chemical fertilizers.


Compost was applied as mulch over inter-rows in the experimental plots.  The organic compost was derived mainly from source separated organic urban waste that was selectively collected.

For all treatments, topsoil samples (0.3m depth) were collected twice (N = 5 per treatment), at the beginning and end of the experiment and before the application of compost/fertilizers.  Composite soil samples were collected by combining two 60mm diameter soil auger cores that were taken in the middle of the inter-row.  Soil physiochemical parameters were measured on all soil samples.

Leaf area was calculated for all treatment plots.  Leaves were removed from half of a plant canopy (three plants per treatment) at veraison, and the following were measured three times throughout the season (May, July, and September): SPAD index, Net CO2 assimilation, and stomatal conductance.

Three grape clusters from each experimental sample vines were randomly collected and weighed.  For the berries, the following were measured: soluble solids concentration (oBrix), titratable acidity, pH, malic acid, and tartaric acid. 

Results

  •       Long-term use of compost to the vineyard (alone or with fertilizers) significantly (and positively) affected soil parameters.

o   There was a slight alkalinization of the soil.
o   There was a significant increase in organic matter in the soil with compost treatment.
§  From 2001 to 2009, organic matter increased 3.5x with the compost treatment, and 2.5x with the compost plus chemical fertilizer treatment.
§  At the end of the entire experiment, soil treated with compost alone had an organic matter content 2.5x higher than the soil treated with the chemical fertilizers alone.
o   There was the same trend for organic carbon content as organic matter (increase with compost treatment).
o   There was a significant increase in total nitrogen content with the compost treatment alone.
§  Total nitrogen was 2x higher in compost only soil compared to chemical fertilizer only soil.
o   Ammonium concentrations significantly increased in the compost treatment, while nitrate concentrations were significantly lower.
  •       Application of compost led to an increase in soil nitrogen, with a mineralizable and stable nitrogen pool and a decrease in soil nitrate levels compared to the chemical fertilizer treatments.
  •        Compost treatment did not significantly affect Chardonnay grapevine growth.

o   Leaf area values were nearly the same for all treatments.
o   There were no significant differences in leaf gas exchange parameters (i.e. net CO2 assimilation, stomatal conductance, and SPAD index).
§  Since CO2 assimilation and stomatal conductance are linked to photosynthesis, these results indicate that compost treatment did not affect photosynthetic performance of the grapevines.
§  There were significant decreases in CO2 assimilation and stomatal conductance at the end of the season, compared to earlier measurements (the same for all treatments), as well as a peak in SPAD index levels.
·         This result is due to the senescence of leaves and does not affect quantity/quality of the grapes.
o   Compost treatment did not have a significant influence on vine growth, nor were there differences between treatments in regards to plant physiological characteristics (CO2 assimilation, stomatal conductance, and SPAD index).
  •       Compost treatment gave varied results over time, depending upon the year/vintage.

o   The number of clusters per plant and the average berry weight were not affected by compost treatment and were not significantly different than the chemical fertilizer control EXCEPT in 2002, 2005, and 2006.
o   Cluster weight was significantly affected by compost treatment EXCEPT in 2003, 2004, and 2005 (no differences detected for those three years).
o   Compost treatment led to a higher production in 2002, 2005, 2007, and 2008 compared to the control chemical fertilizer treatment and a lower production in 2001 and 2006 compared to the control.
o   On average throughout the course of the entire experiment, there were minimal differences among treatments when considering grape production levels.
  •       The pH and oBrix of the grapes was not affected by compost treatment, except in 2006 when oBrix were higher in the compost treatment compared with the control.


Conclusions

Based on the results of this study, the benefits of organic composting are seen primarily in the soil itself, and not as much in the quality/quantity of the grapes produced from the vines planted therein.  The long-term treatment of organic compost to a vineyard can be beneficial for soil characteristics such as organic matter and nitrate content.   Though some years showed significant effects on grape quality, the average for the long-term treatment showed no differences in grape quality with compost-treated soils versus chemical fertilizer-treated soils.

One thing I would have liked to see is how the chemical composition of the grapes changed with organic compost treatment, and not simply berry weight.  Perhaps production remains the same regardless of treatment type, but does the chemical profile of the grape remain the same or change?  How would this affect the resulting wine?

Even though, according to this study, grape quality/quantity remained unchanged with the organic compost treatment, the sheer benefit to the soil itself is reason enough to justify potentially employing the treatment in routine viticultural management practices.  Of course, more work would need to be done.

I’d love to hear what you all think about this study/topic.  Feel free to leave your comments below (no html tags, please).

Source: Mugnai, S., Masi, E., Azzarello, E., and Mancuso, S. 2012. Influence of Long-Term Application of Green Waste Compost on Soil Characteristics and Growth, Yield and Quality of Grape (Vitis vinifera L.). Compost Science and Utilization 20(1): 29-33.




I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!
Apr 24 NO comments
antioxidants, aroma, ecology, environment, flavor, oak barrel, oak chips, phenolics, plants, research, soil, Spain, Spanish oak, storage, wine chemistry, winemaking

Influence of Geographical Location on Volatile Composition of Spanish Oak



The use of oak in wine making, be it with oak barrels or oak chips, has a significant effect on the flavor, aroma, texture, and color of the finished wine.  Traditionally, three different species of oak have been used for wine barrel fermentation and/or aging: Quercus alba L. (American oak), Quercus petraea (Matt.) Liebl., and Quercus robur L (both French oak). As a result of overcropping of the oak trees, or the harvesting off more oak trees than can be regrown for future use, in addition to the quest for more variety, new sources of oak for wine making are being explored.  Oak from Eastern European countries such as Ukraine, Russia, Romania and Hungry are starting to be used more in wine making, including similar species as used in France (Q. petraea and Q. robur) and another species used less frequently: Q. pyrenaica, which frequently hails from Spain.

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The use of oak barrels in wine making significantly influences the volatile composition of the finished wine, which in turn affects the flavor, aroma, and taste of the wine.  Studies have shown that there are quantitative differences in the volatile composition of wine made from American versus French oak barrels.  Furthermore, studies have shown that the Spanish oak, Q. pyrenaica, also shows significant differences in volatile composition of the wood, including higher levels of eugenol, guaiacol, and other volatile phenols and furanic aldehydes.  Looking at phenolic aldehydes and ketones, Spanish oak appears to retain levels between that of French and American oak. 

The amounts of these volatile compounds that are extractable from the oak wood are extremely important in determining the overall aromatic profile of the finished wine.  As a result of this, understanding the chemical composition of Spanish oak (Q. pyrenaica) is extremely important.  Studies from other oak species have shown that there is strong variability in the volatile composition of oak wood within the same species, tree, forest, stand, etc, due to various environmental and geographical factors. 

The study presented today aimed to add to the literature of oak wood volatile composition by examining Spanish oak, Q. pyrenaica, and to evaluate the effect geographical location, site, and silvicultural parameters had on them.

Methods

The sample set included 107 samples of Q. pyrenaica that were collected from several stands in three geographical locations in the northwestern Iberian peninsula (from the provinces of Ourense, Lugo, and Pontevedra).

From each tree, disks of wood were collected at a height of 1.3m above the ground.

From each of these disks, test tubes of heartwood were taken (20mm x 20mm x 40mm).

Heartwood samples were dried, then ground with a mechanical mill and sieved (<1mm) in order to obtain sawdust of a homogenous size.

Volatile compounds were isolated and then analyzed using gas chromatography and mass spectrometry. 

Results

  •       The qualitative profile of volatile compounds obtained from Spanish oak was very similar to what has been reported for other oak species.
  •       There was high variability on several levels, including the levels of individual trees, forests, and geographical locations.
  •       Q. pyrenaica samples were high in cis- and trans-β-methyl-γ-octalactone (cis- was the dominant form).
  •        Samples were high in phenolic aldehydes, including vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde.
  •       Eugenol and isoeugenol were the major phenolic compounds found in all Spanish oak samples.
  •       Phenolic compounds also found in all Spanish oak samples were α-terpinol, γ-cadinene, δ-cadinene, 3-oxo-α-ionol, and vomifoliol (fruity and floral aromas).
  •       The most common semi-volatile present in the samples was β-sitosterol (antioxidant properties).


Silvicultural Parameters

  •       The most influential silvicultural parameter on volatile composition of oak samples was altitude.

o   The volatiles that were most affected were α-terpineol, eugenol, and vitamin E.
o   All correlations were negative:  the higher the altitude, the lower the concentration of volatile compounds.
  •       Organic matter and average annual temperature had some influence on volatile composition, specifically α-terpineol, vanillin, oxo-α-ionol, vitamin E, and α-amyrin.
  •       Distance from tree center, average annual precipitation, and number of trees per hectare did not influence the volatile composition of wood.


Soil Composition

  •       Volatile composition of oak in different soil types was similar.

o   Significant differences were found for the volatile aldehydes syringaldehyde, sinapaldehyde, and coniferaldehyde; and for tritperpenic compounds such as β-amyrin and derivatives and β-sitosterol (all with antioxidant properties).
o   For those compounds with important sensory influence, significant differences were found with α-terpineol, and 3-oxo-α-ionol (floral notes), and trans-β-methyl-γ-octalactone (coconut/woody notes).
  •       The greatest difference for all the above compounds were found in loamy soils.

o   Samples grown in loamy soils had the lowest levels of all of the above volatile compounds.

Geographical Location

  •       Samples from Lugo and Pontevedra were very similar.
  •       Samples from Ourense had lower levels of many volatile compounds compared to the other two locations.

o   Significant differences were found for guaiacol and vinyl guaiacol (smoky odor), syringol, eugenol (clove aroma), α-terpineol (floral odor), and coniferaldehyde.
  •       According to linear discriminate analysis, different geographical locations could determine/distinguish different chemical composition of wood samples of the same species.


Conclusions

The results of this study showed that some silvicultural parameters, such as altitude, organic matter and average annual temperature influence the volatile composition of Spanish oak, Q. pyrenaica.  Conversely, other silvicultural parameters, such as distance from tree center, average annual precipitation, and number of trees per hectare do not influence volatile composition.

Even though it was shown that Q. pyrenaica grown in loamy soils show some significant differences in regards to volatile composition compared to other soil types, linear discriminate analysis showed that soil type is a poor determinant in volatile composition of wood in Spanish oak. On the other hand, as with French and American oak, geographical location does have a significant influence on oak volatile composition, and is a good factor for volatile composition classification.

The results of this study should arm wine makers with information they need in order to make a decision on whether or not Spanish oak is right for the style of wine they wish to create, and which forest/province they should harvest the trees from.  Ultimately, however, I think the next step in this line of research would be to create a wine using barrels from Spanish oak from different geographical locations, and compare the oak volatile composition results with the finished wine volatile content as well as a sensory analysis.

What do you all think of this topic?  How many of you use Spanish oak barrels or Spanish oak chips in your wine making practice?  Please feel free to leave your comments below (no html tags, please).

Source: Alañón, M.E., Pérez-Coello, M.S., Díaz-Maroto, I.J., Martín-Alvarez, P.J., Vila-Lameiro, P., and Díaz-Maroto, M.C. 2011. Influence of geographical location, site and silvicultural parameters, on volatile composition of Quercus pyrenaica Willd. wood used in wine aging. Forest Ecology and Management 262: 124-130.

DOI: 10.1016/j.foreco.2011.03.011



I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!
Apr 05 NO comments
agriculture, bacteria, Botrytis cinerea, contaminants, copper, diversity, ecology, environment, organic, research, soil, Viticulture

Organic Viticulture Methods Alter Microbial Population Structure Towards Natural Biocontrol



As a result of conventional farming practices, many natural habitats have been destroyed, and the plant protection methods employed have not only been thought to cause human health problems, but also contribute to about 30% of greenhouse gas emissions.  One of the purposes of organic farming therefore, is to minimize the impact on the environment, by employing methods such as crop rotation, planting pathogen-resistant crops, the use of limited amounts of chemical pesticides, and the use of natural manure instead of synthetic fertilizers.  It is still a matter of controversy, however, whether or not organic farming methods actually have beneficial effects on biodiversity and microorganism population structures.

http://www.mycology.adelaide.edu.au/
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Out of all the Vitis vinifera grape vines throughout the world, the proportions of those that are grown under organic conditions are steadily increasing.  What has been a source of contention in organic viticulture is the used of copper for plant protection.  In areas near some organically farmed grape vines, there has been high soil contamination of copper, which could potentially harm the plants and animals in that environment, as well as the spread of copper and antibiotic-resistant microbes.

The short study presented today hypothesized that the type of plant protection used in conventional versus organically farmed vineyards would have an impact on the microbial (particularly fungal) community structure.

Methods

Leaves, shoots, and undamaged grapes were sampled from Sauvignon Blanc grapes from vineyards in Schlossberg, Austria during the last week before harvest.  Half of the vineyards were farmed conventionally, and the other half was farmed organically.

Chemicals used for plant protection in the conventional vineyards were: sulfur, paraffin oil, manganese-zinc ethylene bis(dithiocarbamate), proquinazid, iprovalicarb, folpet, pyrimethanil, mandipropamid, quinoxyfen, chloropyrifosmethyl, boscalid, and cyazofamid.  Chemicals used for plant protection in the organic vineyards were: sulfur, copper, Myco-Sin, potassium water glass, Frutogard, and fennel oil.  Four replicates for both conventional and organic vineyards were examined.

DNA fingerprinting was performed to identify microorganisms present.  Once identified, microorganisms were isolated and plated for further analysis.  For all replicates, 18 yeasts and 15 filamentous fungal organisms were isolated and tested for antagonistic activity.

Results

  •       There were statistically significant differences between microbial fingerprints of conventional versus organically managed plots.

o   Fingerprints from organically managed plots were more homogenous and were more similar to each other than conventionally managed plots.
o   The most abundant yeast in the conventionally managed plots was S. pararoseus.
o   The most abundant yeast in the organically managed plots was A. pullulans.
o   Cladosporium sp. and Alternaria tenuissima were common in all plots.
  •       In organically managed plots, a higher abundance of filamentous fungi and yeasts were isolated.
  •       Antiphytopathogenic potential (i.e. ability to protect against Botrytis cinerea, as tested in the laboratory) was greater in organically managed plots than conventionally managed plots.

o   33 out of 34 A. pullulans isolates showed antagonistic activities (i.e. protective abilities) against B. cinerea.
  •       There were no significant differences between organic and conventional plots in regards to bacterial fungal communities (at least in respect to Pseudomonas and Firmicutes bacterial populations).

o   Vineyard management has no influence on bacterial communities (again, at least in respect to Pseudomonas and Firmicutes).

Conclusions

The results of this brief study suggest that the yeast A. pullulans plays a key role in explaining the structural and functional differences between organic and conventional farming methods.  The authors noted that species in the Aureobasidium genus can utilize inorganic sulfur and can absorb/detoxify copper.  This is fascinating since organic viticulture methods use both sulfur and copper in their plant protection strategies, and Aureobasidium pullulans was the most abundant yeast present in organically managed plots.  Also, A. pullulans has been shown to be an effective antagonist against several fungal pathogens, by competing for space and nutrients, as well as producing cell wall-degrading enzymes.  What is also interesting is that A. pullulan produces several typical flavor components in wine, which would be a beneficial characteristic of organic viticulture.

Overall, the type of vineyard management method for plant protection, specifically conventional versus organic management methods, influences the microbial population of the system.  Also, not only was the structure of the community altered, but the function of the community changed as well.  Specifically, in organically managed vineyards, the number of antagonist microorganisms was greatly enhanced due to larger populations of A. pullulans, which could potentially act as a biocontrol agent for B. cinerea (though more work would need to be done to confirm this).

In conclusion, knowing the structure and function of microbial communities is critical for developing environmentally friendly alternatives for plant protection in organically managed vineyards.

I’d love to hear what you all think! Please feel free to comment below (no html tags, please).

Source:  Schmid, F., Moser, G., Müller, H., and Berg, G. 2011. Functional and Structural Microbial Diversity in Organic and Conventional Viticulture: Organic Farming Benefits Natural Biocontrol Agents. Applied and Environmental Microbiology 77(6): 2188-2191.

DOI: 10.1128/AEM.02187-10



I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!
Mar 21 NO comments
agriculture, beaujolais, Burgundy, enology, flavor, france, gamay, gouais blanc, grapes, Pinot Noir, soil, Viticulture, Whos Your Daddy

Who’s Your Daddy?: Gamay



For today’s “Who’s Your Daddy” post, we will be exploring the origins of the Gamay grape.

Also known as Bourguignon noir, Petit Bourguignon, Gamay Beaujolais, Petit Gamai, Blauer Gamet, Gamay noir a jus blanc, and Gamay noir, Gamay is a very old grape that has been certainly mentioned as early as the mid-14th century, though further speculation puts the presence of Gamay grapes in the Burgundy region of France even as early at the 3rd century (unconfirmed).  During the mid-14th century, Gamay was thought to have helped in the recovery of the Black Death, though was later outlawed in 1395 by the Duke of Burgundy Philip the Bold, due to its harshness and overall poor quality relative to its abundance.

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The edict that the Duke of Burgundy signed demanded that Gamay vines be ripped up as they were “despicable and disloyal”.  Later in 1459, the grandson of Philip the Bold, the new Duke of Burgundy Philip the Good, reiterated his family’s disdain for the grape, stating that it could “fool foreigners” (a.k.a. the Christian church).  The Duke continued to urge Burdundy to produce Pinot Noir instead of Gamay, though Gamay was still being produced further south in Beaujolais. 

Gamay is grown primarily in the Burgundy-Beaujolais region of France, as well as the Loire Valley in France and Valais in Switzerland.  Other plantings of Gamay are hard to come by, though it can sometimes be found in vineyards in California after it was introduced there in 1973, and also in regions of Italy, Austria, Romania, Argentina, Chile, and other regions throughout the United States.

In Beaujolais, Gamay is found in Beaujolais Nouveau wines, which are released in a big celebratory manner the third Thursday in November.  Not only are Gamay grapes used in Beaujolais Nouveau wines, but they are also used for Beaujolais Villages, as well as the 10 Beaujolais Crus (Brouilly, Chénas, Chiroubles, Côte de Brouilly, Fleurie, Juliénas, Morgon, Moulin-à-Vent, Regnié and Saint-Amour).

Gamay vines are considered to have relatively early bud break, with moderately vigorous growth.  Gamay vines are best suited for relatively cool climates, with few known limitations in regards to soil type preferences, though does well in soils with granite and limestone.  It is often recommended that Gamay vines be planted on hill slopes, in order to avoid potential high productivity and vigorous vines producing grapes with lower fruit anthocyanins and tannins.  In general, it is recommended to plant Gamay vines in a similar manner to Pinot Noir vines, in medium fertility soils. 

In terms of the wines Gamay grapes produce, they are often higher in acidity, low in tannin, more lightly colored, and fruit forward red wines.  Those that do not enjoy Gamay wines liken the flavor to “melted black cherry Jell-o”.  In order to avoid too high of acidity, Gamay winemaking often employs the use of carbonic maceration (fermenting grapes with carbon dioxide), in order to intensify the grape’s fruity and floral notes, including banana, bubblegum, cotton candy, and vanilla.  Wines produced from Gamay grapes tend to be light-bodied, sometimes with a purple tint.  Most wines made from Gamay grapes are designed to be consumed in their youth, however, some Crus, such as Chénas, Juliénas, Morgon, and Moulin-à-Vent may age up to 10 years.  The younger wines tend to be more fruitful and tropical, whereas the aged wines may have black currant and cherry notes.

So, “Who’s Your Daddy”, Gamay?

Genetic research performed in the late 1990’s at the University of California at Davis has revealed the genetic parentage of many grape varieties, including Gamay. 

Without further ado, Gamay grapes are a product of the parent grapes:

               Pinot Noir……




….and….

http://upload.wikimedia.org/wikipedia/commons/
thumb/7/72/Heunisch-wei%C3%9F08.jpg/
215px-Heunisch-wei%C3%9F08.jpg
......Gouais Blanc





Interestingly, these are the exact same parents as the Chardonnay grape!  Looks like Gamay and Chardonnay are sisters!

Are you familiar with Gamay or Beaujolais wines?  Any favorites?  You’re welcome to comment by leaving your thoughts below!




I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!