Glera: an In-Depth Wine Profile

What is Glera Wine?

Glera represents a classic case of rebranding in the wine world. Formerly called Prosecco, this white grape variety was officially renamed Glera in 2009 as part of a strategic move by Italian wine authorities to protect the geographic designation of wines produced under the Prosecco name. The grape’s history stretches back to Roman times, with some historians suggesting it may have been the vinum pucinum praised by Pliny the Elder. Historical accounts, such as those by figures like Christopher Merret, documented the process of creating sparkling wine through fermentation, highlighting the development and cultural significance of sparkling wine, particularly in the Champagne region.

Originating from the traditionally Slovenian-populated village of Prosecco near Trieste on the Slovenia-Italy border (now in Italy), this variety has found its spiritual home in the hills of northeastern Italy’s Veneto region, where it is primarily grown along with Friuli Venezia Giulia. The name change created a clear distinction between the grape variety (Glera) and the protected wine designation (Prosecco), preventing producers of other regions from labelling their sparkling wines as “Prosecco” merely by using the grape variety’s name. Despite ranking around 30th in importance among Italy’s approximately 2,000 indigenous grape varieties, Glera has secured its place in viticulture history through its key role in producing notable wines like Prosecco.

History and Origin

Glera's history dates back to the Roman Empire in northeastern Italy. Originally known as “Prosecco,” the grape’s name was changed to Glera in 2009 to protect Prosecco wines' identity. This move ensured that only wines from the designated region could be called Prosecco, preserving its heritage. Cultivated for centuries, Glera plays a significant role in Italian winemaking and has also adapted well to regions like Australia, Brazil, and Argentina.

Winemaking Process

Glera’s journey from vineyard to glass features a distinct production method that defines its character. Unlike Champagne, which undergoes secondary fermentation in individual bottles (méthode champenoise), most Prosecco is made using the Charmat method (Martinotti method).

This technique was introduced by Federico Martinotti in 1895 and refined by Eugène Charmat in 1907, revolutionizing sparkling wine production.

Process Overview:

• Extract juice from harvested Glera grapes to produce the base wine.
• Optionally blend with varieties like Verdisso or Bianchetta Trevigiana.
• Add sugar and fresh yeast (liqueur de tirage) to start fermentation.
• Carry out secondary fermentation in pressurized stainless steel tanks (autoclaves).
• Under pressure, carbon dioxide dissolves into the wine.
• Filter and bottle immediately after fermentation (usually within 1–6 weeks).

The Charmat method preserves Glera’s delicate aromatics and fresh fruit character, which are often muted by extended aging in the traditional method.

It also results in softer carbonation—typically 2–4 atmospheres, compared to 5–7 in Champagne—producing the gentle effervescence Prosecco is known for. This production style is a key point of difference.

While traditional-method sparkling wines develop complexity through lees aging, the Charmat method emphasizes Glera’s natural aromatics and primary fruit flavors, without extended contact with grape skins.

Styles of Glera Wines

Glera, the signature grape of Prosecco, is highly versatile and vinified in several styles. While sparkling wines dominate, semi-sparkling and even still versions offer unique ways to experience the grape’s fresh, fruity character.

Main Styles

• Sparkling (Spumante): Fully sparkling wines with lively, persistent bubbles. This is the most common and globally recognized expression of Glera, particularly as Prosecco.
• Semi-Sparkling (Frizzante): Wines with gentler effervescence than Spumante. Labeled as “Frizzante,” they are known for their light, refreshing profile. These wines typically have a pressure of 1–2.5 atmospheres, offering a subtle fizz.
• Still (Tranquillo): A rare, non-sparkling style that shows a pure, fruit-forward profile without bubbles.

Sensory Profile

Glera produces wines with a distinctive sensory signature that makes them immediately recognizable. As a varietal, Glera is relatively neutral with high acidity, making it ideally suited for sparkling wine production.

Premium producers take care to limit the presence of phenolic compounds (compounds from grape skins, seeds, or stems that can contribute bitterness and astringency) during sparkling wine production. High exposure can lead to undesirable tannins, negatively affecting the wine's quality and flavour profile.

Aromatic Profile

Primary Aromas

• Ripe fruit, like white peaches (occasionally with soapy notes)
• Fruity notes of green apple and pear
• Honeydew melon
• Citrus notes
• Occasional presence of banana
• Acacia and wisteria flowers

Secondary Aromas

• Yeasty notes (from the Charmat/fermentation process)
• Cream (subtle, from fermentation)
• Toasted bread or brioche (may be present, especially if there is some lees contact — aging on dead yeast cells)
• Yogurt, milk, or fresh cheese (possible if malolactic fermentation is used — a conversion of malic acid to lactic acid that softens acidity — though less common in most Prosecco styles)

Tertiary Aromas

• Honey (a gentle, sweet note that can develop in aged Glera wines)
• Dried flowers (can appear as the wine ages)
• Dried fruit (such as dried apricot, in rare, more mature examples)
• Almond or nuts (subtle, more likely in older or aged examples)
• Caramel or toffee (very rare, but possible in long-aged or oxidative styles)

Flavor Profile

Structurally, Glera wines are:

• Light-bodied
• Low in alcohol (minimum 8.5% ABV for Prosecco)
• High in refreshing acidity
• Pale straw in colour
• The sparkling wines are characterized by fine, persistent bubbles

The importance of esters (aromatic compounds that give fruity scents) in creating the distinct aroma profiles associated with various fruits cannot be overstated. These compounds contribute to the scents of strawberries, bananas, and pineapples, enhancing the overall sensory experience of the wine.

This sensory profile creates what some might call the “approachability paradox” – Glera’s seemingly simple taste profile actually requires precise cultivation and winemaking to achieve.

The delicate balance of fruit, floral notes, and acidity makes Glera-based wines extraordinarily versatile and appealing to a broad range of palates, contributing to Prosecco’s global popularity.