Terroir Project

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Over the last decade Mendoza Terroir has generally been understood by the wine community as consisting of a uniform collection of alluvial soils. The differences between each site were exclusively determined by altitude and climate.

Since 2008 Altos las Hormigas, with the help of Pedro Parra, South America’s only Soil and Terroir specialist, has started its own Terroir Project, based upon their groundbreaking knowledge on Geomorphology and Soil Profile, and its influence upon wine.

Mendoza soils are alluvial, which means that they have been formed by the action of moving water derived from melted ice from the Andes Mountains. The water, as it travels down from the Andes, drags different kinds of soil elements, eventually depositing them en route to form the soils throughout the ages. Different soils have been shaped depending on the strength of the water flow, the distance from the Andes, and the material that the flow incorporates along its run. All Mendoza soils are formed by a superposition of several layers, corresponding to the different time frames in which they were formed; older soils, being more evolved, are more layered. The layers which bear influence over the Vineyard are those located from the surface to approximately 5/7 feet (1,5 to 2,1 m) in depth, where the roots lie.

Terroir Quality in Mendoza Despite its intricate nature, Mendoza soils and Terroirs can be ranked for wine quality purposes. A simplified list, with drawings by Pedro Parra, includes:

Poor Soil The worst soils are those with poor porosity, mainly formed by silt clay particles, with no pebble presence. These layers prevent irrigation water from penetrating and draining, and therefore make the soil environment difficult for the vine to grow. As water does not penetrate, and the vine root system can only develop in a layer of limited depth, the plant is exposed to both drought when not irrigated, and excess water, when irrigated. Drip irrigation can be used to reduce the imbalances, but the wines typically show green characters if irrigated frequently, or dry tannins if irrigated infrequently. The flavour profile will typically show a lack of depth and persistence. (see left)

A second very common poor terroir profile in Mendoza features deep layers of coarse sand. The excess drainage of these soils, and the lack of clay, needed for micronutrients, makes it almost impossible for the viticulturist to keep the canopy in balance. Therefore, good phenolic ripeness is not achievable. The result again, is a diluted wine with no depth, because of an incomplete evolution of tannins. (see left)

GooGood Soil in Mendoza mainly presents itself in two different forms including deep mixed sandy/clay soils, with good topsoil, showing no compacting layers (layers with excess presence of silt and clay particles) and good porosity, allowing deep root development. This profile produces a good phenolic ripeness, because it can balance the canopy very well, through wet and dry periods. (see right)

The other form is alluvial gravel soil. These soils include 40 to 80 cm (16 to 32 inches) of topsoil, with no gravel and good porosity, followed by a deeper layer with no less than 30% gravel volume. This is a very good terroir for Malbec, but it lacks the clay component in the gravel layer to make it an outstanding terroir. (see left)

Excellent Soil The best Mendoza Terroir is that produced by alluvial terraces. They are homogenous, with a high stone content (30 to 50% of the volume of the soil), and located at no more than 3-5 feet (90 cm to 1,5m) in depth, with enough clay presence in the gravel. When the deep stone layers combine with good topsoil, the wine has the desired depth, due to a very good ripeness of the tannins.

Obviously this is just a very quick overlook at quality ranking. A much finer description can be made, and several more quality brackets can be defined, but the present description suffices for the purpose of this paper

Macro and Microzoning

Micro and macrozoning were studied following the methodology developed by Parra during his PhD Terroir work at Paris University (Institut National Agronomique, Paris). Each method has a different purpose. Combining the vast experience of Carlos Vazquez (over 30 years of Viticulture in Mendoza), with those of Attilio Pagli and Alberto Antonini (over 18 years of winemaking experience with Mendoza Malbec), Parra has been able to use his know-how to draw extensive maps of the Mendoza growing areas, identifying and ranking good and excellent soil areas. Terroir Macrozoning has been applied to select each individual Vineyard responsible for the production of ALH Malbec Classico and ALH Malbec Valle de Uco Terroir.

The Macrozoning map was developed using geomorphologic, topographic and soil analysis on a larger scale. A different Macrozoning map was made for each Mendoza sub region, including La Consulta, Vista Flores, Altamira. This analysis aimed to separate the different alluvial and colluvial phenomena of each area, in order to create an original, quality classification of Mendoza’s macro terroir, based on soil origin. A second step was to verify the draft classification with field work. Our team dug pits in each prospective Vineyard, previously selected by Vazquez, and located in the desired areas of the maps. The soil profiling was completed by Parra himself, analysing each pit on location. The Macrozoning program has allowed ALH to have a clear, scientific classification for every vineyard in which our grapes are sourced, and an evaluation for the aging potential of each site.

Microzoning is a practice undertaken to rank blocks of different soil profile in a single location. It enables us to separate soils with great precision, to determine plots of high consistency and specific character. This kind of research is applied only in extraordinary sites, which have already been identified through Macrozoning and tasted by the ALH technical team (Antonini, Pagli and Vazquez), in order to further fine tune the site production. First, the Vineyard aerial picture is mapped through DGPS, a very high precision satellite system. This position accuracy is key for a row by row micro terroir selection of grapes. The whole Vineyard site is then analysed with two separate methods: electrical conductivity analysis and direct soil analysis. The two analyses are then cross-referenced, to find the areas with outstanding micro terroir features. The Vineyard is, at first, mapped row by row using electrical conductivity of soils, at different depths, normally 75 and 150 cm (30 and 60 inches) in depth. The resulting map highlights the soil variations within the Vineyard.

The Vineyard is then dug in points selected on the map, digging in as many points as necessary (typically one per Ha), and each ditch is analysed visually by Parra on site. This data collection is then analysed again to define those areas of different potential within the Vineyard: areas that will be farmed and harvested individually. Terroir Microzoning has been used to produce ALH Valle de Uco Reserva, and ALH Vistaflores Single Vineyard.

Future Development

The ALH team, together with Pedro Parra, is very excited about the Terroir project. This project will continue in to the foreseeable future, because we believe that we have just scratched the surface of its enormous potential. Our product can be further improved by more field research, and our mapping can be further developed and refined as our field work progresses. Our future aim is to produce wines with more and more Terroir specific personality, of ever improving quality and distinction.

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