Shiraz grape (Vitis vinifera L.)

Shiraz grape (also known as Syrah) is a wine grape variety belonging to the species Vitis vinifera, in the botanical family Vitaceae. The bunches are usually compact, with small to medium berries, a thick dark blue-violet skin and juicy pulp. It is grown in many countries (notably France, Australia, South Africa and Mediterranean wine regions) and adapts well to warm or temperate climates, producing wines with good structure.

As a food “ingredient”, Shiraz grapes are primarily intended for winemaking and are used to produce deeply colored red wines, often showing notes of dark fruits (blackberry, plum), spices (black pepper) and, depending on terroir and ageing, balsamic, toasted or chocolate hints. The berries, like those of other wine grapes, contain sugars, organic acids, polyphenols (including tannins and resveratrol) and small amounts of vitamins and minerals. Fresh consumption is less common than for table grapes, but they can occasionally be used in small quantities in culinary preparations paired with Shiraz wines, such as sauces, reductions or meat dishes.

Common name: Shiraz grape (Syrah)

Parent plant: Vitis vinifera L.

Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Order: Vitales
Family: Vitaceae
Genus: Vitis
Species: Vitis vinifera L.

Note: “Shiraz” and “Syrah” refer to the same grape variety. The name “Syrah” is mainly used in France and much of Europe, while “Shiraz” is common in Australia and some New World regions, often associated with a riper, more opulent style of wine.

Cultivation and growth conditions

Climate

Shiraz/Syrah adapts well to warm and temperate climates, but can also perform nicely in cooler regions.

• Optimal temperatures: 20–30 °C during the growing season.

• Good tolerance to heat, but sensitive to extreme drought.

• In cool climates: more peppery, spicy, and floral aromas, higher acidity.

• In warm/hot climates: riper fruit (plum, blackberry), softer tannins, higher alcohol.

• Requires stable spring conditions; late frosts can damage young shoots.

Sun exposure

Shiraz prefers full sun exposure:

• enhances phenolic ripening,

• increases skin color intensity,

• improves sugar accumulation and aromatic complexity.

In very hot regions, a bit of natural shading from leaves can help prevent berry sunburn.

Soil

Shiraz is fairly adaptable, but gives its best on soils that are:

• well drained,

• from medium to low fertility,

• often rich in stones or gravel (good heat retention and drainage),

• with pH from slightly acidic to slightly alkaline.

Very fertile soils → excessive vegetative growth and less concentrated grapes.
Excellent results are obtained on limestone, volcanic, schist, or well-structured loam soils.

Irrigation

Water requirement is moderate, with good tolerance to controlled water stress:

• Supplemental irrigation can be useful in critical periods to avoid growth stops and shrivel.

• Excess water near veraison and ripening can dilute sugars and phenolics.

• In quality-oriented vineyards, a mild, controlled water deficit is often sought to enhance berry concentration and tannin structure.

Temperature

• Budbreak: around 10–12 °C

• Optimal vegetative growth: 20–28 °C

• Veraison and ripening: 25–32 °C desirable

• Above 35–38 °C, especially with strong sun, berries are at risk of sunburn and desiccation.

In cooler climates, ripening is slower, often resulting in more peppery, fresh, and elegant wines.

Fertilization

• Nitrogen: moderate; excess nitrogen leads to high vigor, shading, and delayed ripening.

• Phosphorus: important for root development and fruit set.

• Potassium: very important for sugar accumulation and color development.

• Organic matter (compost, manure) improves soil structure and microbial activity but should be applied with moderation to avoid over-fertility.

Shiraz generally responds well to moderately poor soils, where vine vigor is naturally controlled.

Crop care

• Winter pruning (Guyot, cordon, etc.) to control vigor and regulate yield.

• Canopy management (leaf removal, shoot positioning) to:

  • improve air flow,

  • optimize sunlight on clusters,

  • reduce disease pressure.

• Main diseases and pests:

  • powdery mildew (to which Syrah can be relatively sensitive),

  • downy mildew,

  • botrytis in humid seasons,

  • grape moths and leafhoppers.

Trellis systems such as vertical shoot positioning (VSP) with Guyot or spur-pruned cordon are common.

Harvest

Harvest timing depends heavily on climate and desired wine style:

• Temperate regions: late summer to early autumn.

• Warmer regions: sometimes mid to late summer.

Ideal maturity targets:

• high but balanced sugar content (for structured wines),

• fully ripe, supple tannins,

• intense skin color.

For top-quality wines, hand harvesting is often preferred to select only healthy, fully ripe clusters.

Propagation

Shiraz is propagated by:

• Grafting onto phylloxera-resistant rootstocks (e.g. 1103 Paulsen, 140 Ruggeri, SO4, Kober 5BB), chosen according to soil type, vigor control, and climatic conditions.

• Hardwood cuttings used in nurseries to produce rootstock and scion material, then grafted.

Vines generally begin producing useful yields after 3–4 years, reaching full production around 5–7 years.

Caloric value (fresh berries, 100 g)
Approximately 65–75 kcal per 100 g (dominated by simple sugars; during winemaking these ferment to ethanol).

Key constituents
Fermentable sugars: glucose and fructose (typical harvest °Brix ≈ 22–25).
Organic acids: tartaric (predominant) and malic; must pH generally 3.3–3.7, TA ≈ 5–7 g/L as tartaric acid.
Polyphenols: anthocyanins (malvidin-3-glucoside predominant), flavonols (quercetin), and tannins from skins and seeds (drivers of color and structure).
Aroma/precursors: minor terpenes and norisoprenoids; rotundone (a sesquiterpene linked to black-pepper notes); trace sulfur compounds.
Yeast nutrients: YAN (yeast-assimilable nitrogen) varies and is critical for healthy fermentation kinetics.

Production process
Viticulture: Canopy management for sugar/acid balance and sunburn control; targeted leaf removal to influence phenolic development and cluster health. Moderate yields favor concentration.
Harvest: Timed by °Brix, pH, TA, and phenolic maturity (seed/skin); hand or machine harvest with sorting.
Red vinification: Destemming and optional crushing; controlled sulfiting; yeast inoculation; skin maceration (several days to >20) with pump-overs or délestage; temperature management; optional post-fermentation maceration. Pressing and racking follow; malolactic fermentation as desired.
Maturation: Steel or concrete for fruit-driven styles; oak (barrique/tonneau/large casks) for tannin integration and complexity; oxygen management with attention to TPO.
Alternative styles: Rosé via saignée; historic co-fermentation with small portions of white grapes in some regions to stabilize color and lift aromatics.
Bottling: Tartaric/protein stability, filtration, final sulfiting, and control of dissolved oxygen (DO).

Sensory and technological properties
Color: Deep ruby-purple owing to high anthocyanin content.
Aromas: Dark berries (blackberry, plum), violet; black pepper (rotundone) is more evident in cooler conditions; warmer climates emphasize ripe blackberry, licorice, and occasional chocolate notes.
Palate: Medium- to full-bodied, medium-to-firm tannins; moderate acidity; potential alcohol 13–15.5% ABV depending on ripeness.
Technology: Strong extractive capacity; maceration time/temperature balance color and tannin; micro-oxygenation or oak aids polymerization and integration.

Food applications
Predominantly red still wines across a broad stylistic range; rosé; blending with other varieties; pomace distillates; wine vinegars; culinary use of must/wine in reductions and sauces.

Nutrition and health
Grapes provide water, simple sugars, and polyphenols; in wine, the presence of alcohol necessitates responsible consumption. Polyphenols drive color/astringency; nutritional impact depends on portion and dietary context.

Quality and specification themes
Grapes: Target °Brix 22–25 with coherent TA/pH, microbiological soundness, residues within limits; intact skins/seeds.
Must/wine: Color (anthocyanin index), TPI (total polyphenol index), YAN, fermentation kinetics; SO₂ free/total; turbidity/filtration index; DO/TPO under control; tartaric stability.
Compliance with appellation/production standards, full traceability, and cellar GMP.

Storage and shelf life
Grapes: Pre-processing cold chain, protection from oxidation/contamination; short intervals between harvest and crushing.
Wine: Stable temperature, darkness, low DO; suitable glass and closures; SO₂ monitoring over time.

Allergens and safety
Grapes are not a listed major allergen; wines contain sulfites (added or endogenous) and must be labeled accordingly. Cellar hygiene should prevent spoilage organisms (e.g., Brettanomyces and volatile phenols).

Cosmetic (INCI) functions
Common grape-derived entries include Vitis Vinifera (Grape) Seed Oil (emollient/occlusive) and Vitis Vinifera (Grape) Fruit/Leaf/Skin Extract (antioxidant, skin conditioning, mild astringent). Grape-seed oil is appreciated for its PUFA/MUFA profile and tocopherols; skin/seed extracts for proanthocyanidins.

Troubleshooting
Muted pepper note: Over-ripe fruit or warm ferment → Advance harvest slightly, cool fruit/must, and manage reductively to retain rotundone.
Hard/astringent tannins: Over-extraction or unripe seeds → Shorten maceration, avoid seed breakage, and consider oak integration or micro-oxygenation.
Sluggish/stuck fermentation: Low YAN or sub-optimal temperature → Supplement nutrients and manage inoculation/thermal profile.
Premature oxidation: Elevated DO/TPO → Improve inert gas practices, headspace control, and oxygen barriers.
Animal/phenolic faults: Brett contamination → Barrel sanitation, adequate SO₂, and strict hygiene.

Sustainability and supply chain
Integrated/organic viticulture, careful water/energy management, reduced copper/sulfur inputs, recovery of by-products (skins, seeds), and effluent control against BOD/COD targets reduce footprint. Lightweight/recyclable packaging and efficient logistics further lower emissions.

Conclusion
Shiraz delivers stylistic versatility and a distinctive sensory profile—deep color, spice, and dark fruit. Quality hinges on technological and phenolic ripeness, disciplined maceration and oxygen management, and well-chosen maturation; with these controls, stable, expressive, and age-worthy wines are achievable.

Mini-glossary
°Brix — Percent soluble solids in must; proxy for sugar ripeness.
pH — Acidity measure affecting color stability, extraction, and microbial ecology.
TA — Titratable acidity (as tartaric g/L); gauges acid “backbone.”
YAN — Yeast-assimilable nitrogen; key nutrient pool for fermentation.
TPI — Total polyphenol index; spectrophotometric estimate of phenolic load/structure.
SO₂ — Sulfur dioxide (free/total); antioxidant and antimicrobial in oenology.
DO — Dissolved oxygen; oxygen in wine prior to/separate from packaging.
TPO — Total package oxygen; oxygen present at bottling in wine plus headspace.
ABV — Alcohol by volume; volumetric alcohol content of wine.
PUFA/MUFA — Poly/monounsaturated fatty acids; lipid classes relevant to grape-seed oil.
BOD/COD — Biochemical/chemical oxygen demand; effluent organic-load indicators.
GMP — Good manufacturing practice; cellar process and hygiene standards.
Sulfites — Sulfur-based preservatives/antioxidants in wine; labeling required where present.

References__________________________________________________________________________

Kang W, Bindon KA, Wang X, Muhlack RA, Smith PA, Niimi J, Bastian SEP. Chemical and Sensory Impacts of Accentuated Cut Edges (ACE) Grape Must Polyphenol Extraction Technique on Shiraz Wines. Foods. 2020 Jul 31;9(8):1027. doi: 10.3390/foods9081027.

Abstract. Accentuated Cut Edges (ACE) is a recently developed grape must extraction technique, which mechanically breaks grape skins into small fragments but maintains seed integrity. This study was the first to elucidate the effect of ACE on Shiraz wine's basic chemical composition, colour, phenolic compounds, polysaccharides and sensory profiles. A further aim was to investigate any potential influence provided by ACE on the pre-fermentation water addition to must. ACE did not visually affect Shiraz wine colour, but significantly enhanced the concentration of tannin and total phenolics. Wine polysaccharide concentration was mainly increased in response to the maceration time rather than the ACE technique. ACE appeared to increase the earthy/dusty flavour, possibly due to the different precursors released by the greater skin breakage. The pre-fermentation addition of the water diluted the wine aromas, flavours and astringency profiles. However, combining the ACE technique with water addition enhanced the wine textural quality by increasing the intensities of the crucial astringent wine quality sub-qualities, adhesive and graininess. Furthermore, insights into the chemical factors influencing the astringency sensations were provided in this study. This research indicates that wine producers may use ACE with pre-fermentation water dilution to reduce the wine alcohol level but maintain important textural components.

Antalick G, Šuklje K, Blackman JW, Meeks C, Deloire A, Schmidtke LM. Influence of Grape Composition on Red Wine Ester Profile: Comparison between Cabernet Sauvignon and Shiraz Cultivars from Australian Warm Climate. J Agric Food Chem. 2015 May 13;63(18):4664-72. doi: 10.1021/acs.jafc.5b00966. 

Abstract. The relationship between grape composition and subsequent red wine ester profile was examined. Cabernet Sauvignon and Shiraz, from the same Australian very warm climate vineyard, were harvested at two different stages of maturity and triplicate wines were vinified. Grape analyses focused on nitrogen and lipid composition by measuring 18 amino acids by HPLC-FLD, 3 polyunsaturated fatty acids, and 6 C6-compounds derived from lipid degradation by GC-MS. Twenty esters and four higher alcohols were analyzed in wines by HS-SPME-GC-MS. Concentrations of the ethyl esters of branched acids were significantly affected by grape maturity, but the variations were inconsistent between cultivars. Small relative variations were observed between wines for ethyl esters of fatty acids, whereas higher alcohol acetates displayed the most obvious differences with concentrations ranging from 1.5- to 26-fold higher in Shiraz than in Cabernet Sauvignon wines regardless of the grape maturity. Grape analyses revealed the variations of wine ester composition might be related to specific grape juice nitrogen composition and lipid metabolism. To the authors' knowledge the present study is the first to investigate varietal differences in the ester profiles of Shiraz and Cabernet Sauvignon wines made with grapes harvested at different maturity stages.

Davies C, Nicholson EL, Böttcher C, Burbidge CA, Bastian SE, Harvey KE, Huang AC, Taylor DK, Boss PK. Shiraz wines made from grape berries (Vitis vinifera) delayed in ripening by plant growth regulator treatment have elevated rotundone concentrations and "pepper" flavor and aroma. J Agric Food Chem. 2015 Mar 4;63(8):2137-44. doi: 10.1021/jf505491d.

Abstract. Preveraison treatment of Shiraz berries with either 1-naphthaleneacetic acid (NAA) or Ethrel delayed the onset of ripening and harvest. NAA was more effective than Ethrel, delaying harvest by 23 days, compared to 6 days for Ethrel. Sensory analysis of wines from NAA-treated fruit showed significant differences in 10 attributes, including higher "pepper" flavor and aroma compared to those of the control wines. A nontargeted analysis of headspace volatiles revealed modest differences between wines made from control and NAA- or Ethrel-treated berries. However, the concentration of rotundone, the metabolite responsible for the pepper character, was below the level of detection by solid phase microextraction-gas chromatography-mass spectrometry in control wines, low in Ethrel wines (2 ng/L), and much higher in NAA wines (29 ng/L). Thus, NAA, and to a lesser extent Ethrel, treatment of grapes during the preveraison period can delay ripening and enhance rotundone concentrations in Shiraz fruit, thereby enhancing wine "peppery" attributes.

Fang Y, Kravchuk O, Taylor DK. Chemical Changes in Grape Stem and Their Relationship to Stem Color throughout Berry Ripening in Vitis vinifera L. cv Shiraz. J Agric Food Chem. 2015 Feb 4;63(4):1242-1250. doi: 10.1021/jf504215e. 

Abstract. Little attention has been paid to the color change or chemical compositional changes that occur in grape stems and how this correlates with the berry ripening process. Recently we have found that the change in grape peduncle color of Shiraz (Vitis vinifera) from green at veraison to predominantly brown at harvest occurs in parallel with berry ripening and as such may represent a new way of assisting in the prediction of grape maturity and harvest date. We have now investigated further the link between certain key chemical compositional changes that occur in the grape stem (peduncle and rachis) from veraison to harvest and how these attributes correlate with the observed color change in the vineyard. We report that peduncle moisture content has an excellent linear correlation with the color hue value and is negatively correlated in a strong fashion with the chlorophyll and carotenoid pigment ratio (Ca+b/Cx+c) within the peduncles. Significant differences in the moisture content, total chlorophylls (including chlorophyll a and b levels), total carotenoids, total phenolics, and the antioxidant capacity (DPPH) levels between the peduncles and rachises were found as they evolve from veraison to harvest. Finally, we have demonstrated for the first time that peduncle moisture content codevelops with the prototypical berry ripeness parameters (oBrix, pH, TA), which provides for the development of a new approach for viticulturists and winemakers to evaluate grape ripeness through peduncle moisture levels and therefore assist in harvest decision making.

Boss PK, Davies C, Robinson SP. Analysis of the Expression of Anthocyanin Pathway Genes in Developing Vitis vinifera L. cv Shiraz Grape Berries and the Implications for Pathway Regulation. Plant Physiol. 1996 Aug;111(4):1059-1066. doi: 10.1104/pp.111.4.1059. 

Abstract. Anthocyanin synthesis in Vitis vinifera L. cv Shiraz grape berries began 10 weeks postflowering and continued throughout berry ripening. Expression of seven genes of the anthocyanin biosynthetic pathway (phenylalanine ammonia lyase [PAL], chalcone synthase [CHS], chalcone isomerase [CHI], flavanone-3-hydroxylase [F3H], dihydroflavonol 4-reductase [DFR], leucoanthocyanidin dioxygen-ase [LDOX], and UDP glucose-flavonoid 3-o-glucosyl transferase [UFGT]) was determined. In flowers and grape berry skins, expression of all of the genes, except UFGT, was detected up to 4 weeks postflowering, followed by a reduction in this expression 6 to 8 weeks postflowering. Expression of CHS, CHI, F3H, DFR, LDOX, and UFGT then increased 10 weeks postflowering, coinciding with the onset of anthocyanin synthesis. In grape berry flesh, no PAL or UFGT expression was detected at any stage of development, but CHS, CHI, F3H, DFR, and LDOX were expressed up to 4 weeks postflowering. These results indicate that the onset of anthocyanin synthesis in ripening grape berry skins coincides with a coordinated increase in expression of a number of genes in the anthocyanin biosynthetic pathway, suggesting the involvement of regulatory genes. UFGT is regulated independently of the other genes, suggesting that in grapes the major control point in this pathway is later than that observed in maize, petunia, and snapdragon.

Garrido-Bañuelos G, Buica A, Schückel J, Zietsman AJJ, Willats WGT, Moore JP, Du Toit WJ. Investigating the relationship between grape cell wall polysaccharide composition and the extractability of phenolic compounds into Shiraz wines. Part I: Vintage and ripeness effects. Food Chem. 2019 Apr 25;278:36-46. doi: 10.1016/j.foodchem.2018.10.134. Epub 2018 Oct 30. PMID: 30583384.

Garrido-Bañuelos G, Buica A, Schückel J, Zietsman AJJ, Willats WGT, Moore JP, Du Toit WJ. Investigating the relationship between cell wall polysaccharide composition and the extractability of grape phenolic compounds into Shiraz wines. Part II: Extractability during fermentation into wines made from grapes of different ripeness levels. Food Chem. 2019 Apr 25;278:26-35. doi: 10.1016/j.foodchem.2018.10.136. Epub 2018 Oct 30. PMID: 30583371.

Souza EL, Nascimento TS, Magalhães CM, Barreto GA, Leal IL, Dos Anjos JP, Machado BAS. Development and Characterization of Powdered Antioxidant Compounds Made from Shiraz (Vitis vinifera L.) Grape Peels and Arrowroot (Maranta arundinacea L.). ScientificWorldJournal. 2022 Apr 26;2022:7664321. doi: 10.1155/2022/7664321.