Dinnella, C., E. Monteleone, N. Condelli and V. Iannelli (2005). Effects of Altitude on Aglianico Grapes Composition at Different Stages of Maturity. International Workshop on Advances in Grapevine and Wine Research, Venosa, Italy, 2005.
Grape phenolic profile strongly influences the characteristics of the resulting wine in terms of sensory properties, such as colour, bitterness and astringency, which are considered important determinants of wine quality. Wines from Aglianico grape show strong colour intensities. Astringent, bitter and sour are the dominant descriptors of sensations perceived when tasting these wines. The ripening stage of grapes is one of the main factors influencing their phenolic composition. Harvesting time is usually determined on the basis of technological indices related to barriers weight, sugar content and acidity. Several investigations demonstrated the lack of constant correlations amongst these technological parameters and grape phenolic composition. On the other hand, the evolution of phenolics during wine aging towards stable coloured pigments as well as less astringent or less bitter compounds strictly depends from grape “phenolic maturity”. The main objective of this work was to study the effect of vineyard altimetry on evolution of Aglianico grapes composition in terms both of technological indices and phenolic profile during berries ripening. Grapes from vineyard at three different altitude (L: 200-300, M: 300-350 and H:400-550 mt) were collected at different ripening stages. Phenolic maturity and anthocyanins profile were assayed. Antioxidant activity and reactivity with mucin of grape phenolic extracts were determined. taking into account their relationship with phenol polymerisation degree and potential contribution to wine astringency, respectively. Principal Component Analysis of data indicate that grapes from L and M altitude levels are characterized by better technological indices and higher values of phenols and anthocyanins in respect to grapes from H level. Moreover seeds tannin from L and M levels resulted to be more polymerized and less reactive towards to proteins in respect to samples from H level. A delay in harvesting time of grape from H altitude level could partially overcome the relative weakness of its phenolic profile by increasing both phenol extractability index and anthocyanin concentration.
Dutt, G. R., E.A. Mielke, and W.H. Wolfe (1981). “The Use of Soils for the Delineation of Viticultural Zones in the Four Corners Region.” Am. J. Enol. Vitic 32(4): 290-296.
Delineation of viticultural zones has been useful in making varietal recommendations and predicting wine quality. The California base 50 growing-degree-day model fails to predict zones in the Four Corners Region which are comparable to California, either in adaptable varieties, sugar and acid or color of red varieties. A new model has been developed based on modern soil surveys and altitude. The soil parameter most useful in describing viticultural adaptability is the mean annual soil temperature at 50 cm. This parameter subdivides soils into hyperthermic, thermic and messic. Most wine grapes in California are produced on thermic soils, hence, this soil group has been subdivided. Altitude (inter-related to temperature) is the secondary parameter. Zones defined are HT (hypothermic), T1 (low-level thermic), Tm (mid-level thermic), Th (high-level thermic), and M (messic). This system while encompassing the G.D.D. concept, allows for wider climatic conditions to be considered.
Failla, O., L. Mariani, L. Brancadoro, R. Minelli, A. Scienza, G. Murada, and S. Mancini (2004). “Spatial Distribution of Solar Radiation and Its Effects on Vine Phenology and Grape Ripening in an Alpine Environment.” Am. J. Enol. Vitic 55(2): 128-138.
Climate, soil, and vineyard performance were characterized in the northern Italian alpine valley of Valtellina to develop an ecophysiological model for zoning viticultural aptitude of the district. Based on a representative sample of 54 small, steep-sloped terraced vineyards planted with the late-ripening red cv. Nebbiolo, the model included three-year (1998 to 2000) data sets for phenology, maturity curves, yield, vigor, and grape assays, with appropriate indices to manage these sets. Soils were characterized by pedological description and climate by annual values of potential photosynthetically active radiation (PPAR) and estimated thermal fields expressed as growing degree days (GDD) using base 10°C. PPAR ranged from 2700 to 3200 MJm-2year-1 and GDD ranged from 1100 to 1800. Vineyards showed a 12-day range in phenological timing, with early sites having the highest technological maturity and medium sites having the highest phenolic maturity. Elevation and PPAR were the main environmental factors affecting vine budbreak and bloom date; veraison was also affected by crop load and its interaction with PPAR availability. Technological maturity was affected by elevation; phenolic maturity by crop load, PPAR, and its interaction with crop load and elevation. The highest phenolic maturity was recorded in lowcropping vineyards at low elevation and PPAR.
Haba, M., A. Mulet, and A. Berna (1997). “Stability in Wine differentiation of Two Close Viticultural Zones.” Am. J. Enol. Vitic 48(3): 285-290.
Pattern recognition techniques were applied to the discrimination of wines from two very close viticultural regions. They are two zones in the Utiel-Requena region (Valencia, Spain) of Certified Origin centered in the Utiel and Requena towns, respectively. The differentiation is due to various climatic factors, since soil characteristics are very similar and the cultivars are the same. This climatic differences influence the degree of ripeness attained The differences in altitude of the zones account for their climatic differences. This study focused on data corresponding to rosé wines (Bobal cultivar) from the 1988 vintage. Discriminant analysis showed that four variables (ethanol, anthocyanins, K, and Na) allowed a satisfactory zone classification of these rosé wines (93.5% well classified). The application of the discriminant analysis results to a series of wines of the same year, not considered previously, has also led to successful results (90.6% well classified). In order to evaluate the discriminant power of these variables, the study was broadened to include a longer period (1987-1994). In each case, the analysis was similar although data used were only those corresponding to the four variables above-mentioned. In all cases, the classification was acceptable (90.7% well classified on average and better than 81% in each individual case), thus showing the stability of the discriminant variables along a period of eight years. The influence of the climate (year) is demonstrated through the variation of the discriminant variables coefficients.
Mateus, N. (2001). “Proanthocyanidin Composition of Red Vitis vinifera Varieties from the Douro Valley during Ripening: Influence of Cultivation Altitude.” Am. J. Enol. Vitic 52(2): 115 – 121.
The effect of altitude and its related climatic conditions on the proanthocyanidin composition of Touriga Nacional and Touriga Francesa varieties during berry maturation is reported for the 1997 vintage. At berry maturation, low altitude is shown to be an important factor favoring the biosynthesis of higher concentrations of grape-skin catechin monomers ((+)-catechin, (-)-epicatechin gallate), procyanidin dimers, trimer C1, as well as total extractable proanthocyanidins. At harvest, grape-skin dimer conted was comprised almost entirely of dimer B1, followed by dimers B2 and B3, whereas Ca-C8 linked dimers (B1 to B4) and B2-gallate were the most abundant found in seeds. Dimer B2, which was one of the less important dimers at the early stage of development in seeds, showed a tendency to increase during ripening, while its respective gallate ester (B2-gallate) markedly decreased.
Mateus, N., S. Proenca, P. Ribeiro, J.M. Machado, and V. de Freitas (2001). “Grape Wine Polyphenolic Composition of Red Vitis Vinifera Varieties Concerning Vineyard Altitude.” Ciencia y Tecnologia a Alimentaria 3(002): 102 -110.
Myburgh, P. (2005). “Effect of altitude and distance from the Atlantic Ocean on mean February temperatures in the Western Cape Coastal region.” Wine Land.
Mean February temperature is one of the parameters used to select the most suitable locality for a specific wine grape cultivar. However, temperature data is not always available for all localities or vineyards. Decisions often depend on information gathered at the nearest weather station, which does not necessarily represent the situation at the specific locality. Processing existing data showed that the mean February temperature declines at a rate of ca. 0.5°C with a 100 m increase in altitude and increases by ca. 0.6°C per 10 kilometre increase in distance away from the ocean. If the altitude and distance from the Atlantic Ocean for a specific locality is known, it could be used in an elementary model to obtain an indication of the mean February temperature. However, factors such as slope and aspect, as well as the effects of topography on air flow and the occurrence of fog, may cause a varying degree of temperature deviations at specific localities.
Pfeifer, M. T., P. Koepke, and J. Reuder. (2006). “Effects of altitude and aerosol on UV Radiation.” Journal of Geophysical Research 111.
Measurements of erythemally weighted UV radiation during about 600 days at different sites in Bolivia and Germany ranging from 550 to 5240 m above sea level have been used to derive the altitude effect AE under cloud-free conditions. In Germany, AE values between 7 and 16%/km have been obtained. In Bolivia, the altitude effect between the lowlands and the Bolivian plateau reached values of 5-10%/km. An altitude effect of 8-23%/km has been measured between the plateau and a high-mountain station. In accordance with previous studies these results indicate that the altitude effect of UV irradiance cannot be described by a single number in %/km, because it strongly depends on the atmospheric and surface parameters. In order to understand the high variability of the AE, the effects due to variations in solar elevation, albedo, and aerosol properties on UV radiation and the AE have been analyzed. To eliminate the influence of clouds, an algorithm for the selection of cloud-free time intervals has been developed and applied. Furthermore, the measured data have been normalized to a fixed ozone content to avoid masking of the AE by different ozone amount. In addition, the background altitude effect, i.e., the AE resulting only from the reduced barometric pressure and reduced ozone content with increasing altitude, has been modeled. Depending on solar elevation and albedo, it ranges between 3 and 7%/km. Measured higher values of the AE, as well as negative values of the AE, are explained by the specific regional aerosol conditions, with important sources at high altitudes. The aerosol influence on UV is shown in detail for extreme conditions after strong bonfires in connection with a local holiday.