In 1895, ingenious Italian researcher and enologist Federico Martinotti developed a revolutionary method for producing sparkling wine. The method, which now bears his name, involves the vinification of a base still wine followed by a second fermentation in an autoclave, during which the wine naturally acquires its characteristic fine bubbles and the qualities of the Glera grape are enhanced. While mostly widely known as the Charmat method, after Frenchman Eugène Charmat patented the pressurised stainless-steel tanks used in the process in 1910, Martinotti is the method’s inventor.
The Conegliano Valdobbiadene region, with its distinctive humpy hogback hills and narrow cultivated terraces known as ciglioni, is the true heartland of the Martinotti method. The method was swiftly adopted in the first half of the past century, gradually replacing the traditional metodo ancestrale, which involved a second fermentation in the bottle with no disgorgement.
‘The adoption of the Martinotti method in the Conegliano Valdobbiadene region did not happen casually,’ explains Diego Tommasi, a leading wine scientist and the director of the Consorzio di Tutela del Conegliano Valdobbiadene Prosecco DOCG. ‘It was a deliberate choice, driven by the fact that the method was perfectly suited to preserve the complex nuances of the Glera grape and showcase the different terroirs where it grows.’
Indeed, despite it being no larger than the city of Bristol, the Conegliano Valdobbiadene Prosecco DOCG area boasts an extraordinary diversity of microclimates. Its 43 rive, or single hills, are a testament to this heterogeneity, which arises from elevations ranging from 50 to 500 metres, as well as factors such as varying vineyard exposures, slopes, and nine distinct soil types. The delicately aromatic Glera grape is especially sensitive to these diverse growing conditions, and the Martinotti method is ideally suited to showcase its multifaceted character in the resulting wines.
Glera is the protagonist
Andrea Miotto, winemaker and owner at the family-run Cantina Miotto, emphasises that producing high-quality Martinotti method sparkling wines requires perfectly ripe, hand-picked grapes. ‘Hand-picking is quite normal in our region due to the steep, hilly landscape,’ he explains. ‘The fruit must be fully mature because the limited sugar that Glera accumulates – just enough to reach 10-11% ABV – is all essential for a balanced wine.’
The initial gentle press of the whole bunches, which prevent transferring green tannins into the must, is reserved for the finest expressions of Conegliano Valdobbiadene Prosecco Superiore DOCG, while subsequent pressings are fermented separately and used to fine-tune the wines’ phenolic character or structure.
The Martinotti method is ideally suited to showcase the Glera grape’s multifaceted character
Individual plots are frequently fermented separately, too, with their terroir expression guiding the style of wine they produce. Fruit with slightly higher pH levels, for instance, is used for wines with less residual sugar, such as Brut Nature or Extra Brut. Conversely, grapes with high acidity levels of up to 7 or 8 g/L are selected for more indulgent styles like Extra Dry or Dry, lending them remarkable balance, freshness of fruit, and mineral character despite the higher residual sugar.
Some winemakers choose to mature the wine on the lees after the first fermentation to enhance its volume and structure while preserving its territorial identity. ‘Lees contact of five to six months is very effective for improving the wine’s structure,’ says Miotto. The process, however, requires great care: with only 6-8% ABV, the partially fermented base wine is susceptible to bacterial alterations or reduction, which can spoil its organoleptic profile, or trigger the unwanted onset of malolactic conversion. ‘This extended maturation is very delicate and significantly lengthens the production time,’ he says, ‘but it ensures that the base wines reach the right level of maturation before the next steps, particularly crucial for the finest Martinotti method wines, such as Rive and Cartizze.’
The ‘presa di spuma’
Still uncarbonated, the base wines undergo a second fermentation in an autoclave. It is a key stage in the Martinotti method as it’s when the liquid acquires its precious bubbles – the ‘presa di spuma’, as it’s known in these hills.
‘The fermentation is stopped by chilling the wine as soon as it reaches the desired pressure – generally five bars or more – and the target residual sugar,’ explains Luigi Stramare Bortolomiol, winemaker of Spumanti Gemin. ‘This means that no dosage is needed before bottling.’
After the secondary fermentation, the wines go through an additional maturation period in autoclave for the final stabilisation. The minimum time a wine must spend in the autoclave before release is 30 days, though in Conegliano Valdobbiadene, this is often extended considerably. A period of two or three months is common, as it preserves varietal character while adding depth. However, some extend it further, up to seven or eight months, for a deeper mouthfeel and a hint of autolytic character to complement the wine’s fruit expression.
While all resulting wines showcase the distinctive floral elegance, fresh fruit, and mineral quality of the Glera grape, the outcomes of this laborious and fascinatingly nuanced method of producing fine spumante are as diverse as the terroirs of Conegliano Valdobbiadene.
The exceptional nature of these wines is increasingly driving winemakers worldwide – from Britain’s Divergent Drinks and Flint Vineyards to Brazil’s Tenuta Foppa & Ambrosi – to embrace the Martinotti method as a tool for crafting liquids of distinct character and superior quality. A remarkable process that celebrates, rather than overshadows, the grape’s true identity, allowing its personality and the uniqueness of its place of origin to shine through in the glass.
