How does Soil affect a Wine?
SAME ESTATE, SAME CULTIVAR, SAME VINE-GROWING, SAME WINEMAKING, SAME VINTAGE – DIFFERENT SOILS
Monday 24 April 2020
Dr Peter Rating – Experience: 5/5
Dr Peter Rating – Wine: 4/5
Soil is an integral element of terroir together with climate, terrain and winemaking tradition. It is the synergy of these natural and man-made factors that give a wine its unique and identifiable character. The effect of soil type on the taste of a wine is a topic that has long fascinated and continues to do so. South African lockdown meant that I had to postpone my Dr Peter Master Class ‘Soils’ tasting. The aim was to compare like wines of varying cultivars from different soils and to see if any consensus or consistent conclusion could be drawn amid those at the tasting. The event was not to be, for the moment at least, but I did happen upon 2 Lomond wines that well suited a comparison for one of the ‘Taste Live with Dr Peter’ daily 6pm live tastings hosted on Facebook by the Cape Wine Lovers’ Society.
Lomond was the 100th estate that I visited and tasted wines for review on the www.capewinelover.co.za website. I remember it well, travelling 3 hours from Cape Town to the Agulhas wine District. The vast estate on the Agulhas Plain has 120 hectares of 1,100 hectares under vine and grows a broad range of Bordeaux and Rhône varieties. It lies 8 km from Gansbaai and so gains the benefit of cooling South-East and South-West breezes to keep February temperatures below 30ºC on slopes that are 50-100 metres above sea level. The large property brings with it 18 different soil types and so perfect for terroir-cultivar matching, as well as the potential to taste wines from differing soils. All the wines are named after the local fynbos and indigenous plant species.
The 2 Sauvignons Blanc were from the same wine estate, of the same 2017 vintage, grown on high East-facing vineyards and made by the same winemaker. The grapes were hand-harvested, fermented at a cool cool 13-15ºC in neutral steel tanks and underwent 8 weeks on the lees before bottling.
Soils differ in their fertility, nutrient and organic matter content, water retention ability, temperature and a whole host of other factors. These all impact on the character of the wine. Fine clay is cool and retains water. This, as theory suggests, makes for a fuller bodied wine with a higher extract and colour. In contrast, sandy loam – loam being a fertile soil with a near equal mix of silt, clay, sand and organic humus – is well-drained and retains heat. This produces eelegant wines with high aromatics, pale colour and low tannins.
The Tasting Note of the Sugarbush Sauvignon Blanc, from clay soils, describes a nose with “aromas of citrus, with distinctive minerality, layers of herbaceous flavours and Cape fynbos”. Further, the taste has “full-bodied, clean, mineral tones with gooseberry purity”. The Pincushion, in contrast, from sandy loam soils promises a bouquet that is “elegant, driven by minerality and citrus nuances” together with a taste with “flavours of tropical fruit with a hint of citrus”.
The theory set. The full-bodied label description of full body and elegance for the Sugarbush and Pincushion, respectively, certainly matches the clay soil and sandy loam theory expectation. Will it prove to be in tasting practice? There was only once way to find out as I filled 2 glasses equally for side by side comparison at the Dr Peter Live tasting. There was little difference to their pale lemon colour, so I assessed both wines for the Nose.
The Sugarbush (clay) showed fresh primary fruit aromas of fresh lime, grapefruit and unripe lemon citrus together a delicate florality and notes of English gooseberry that were reminiscent of a Marlborough, New Zealand Sauvignon Blanc. The Nose of the Pincushion (sandy loam) was very different. There were fewer green and herbaceous notes. Instead, the aromas were of stone fruits and of melon, kiwi and ripe lemon with less perfume. I checked the minerality after. Both wines showed some minerality on the nose – a slight salinity – but it was not very intense.
The differences on the Nose followed through on the Palate. The clay-soil Sugarbush Sauvignon Blanc was elegant on the Palate with good balance between the fresh fruits, medium alcohol and a bright, integrated acidity. I liked the clean, crisp texture. The Pincushion, from the sandy loam soil, was likewise well balanced but with a fuller mouthfeel and weight. The wine showed warmer tropical fruit flavours but with poise, elegance and finesse.
The comparison was fascinating, and the theory was mostly borne out by the tasting. The effect of the cooler, damper clay soil certainly contributed to the fresh citrus fruit aromas and flavours of the Sugarbush wine whilst the Pincushion (sandy loam) had the expected a warmer, more tropical and less herbaceous fruit profile. The relative fullness of the Pincushion was not anticipated but the warmer fruits could have confused, yet the greater elegance was expected.
I am now keener than ever to try this tasting experiment again with the other wines I have that are identical but for their soils. Alas, I shall Have to wait for lockdown to end to be able to arrange that tasting.