1) Grape picking
Usually, the grapes are picked between the end of September and mid-October, around 100 days after the vines have flowered. This is when the grapes are ripest. As required by the champagne appellation rules, picking is exclusively by hand, vineyard parcel by vineyard parcel, bunch by bunch. For about three weeks, the House of G.H.MUMM employs approximately 1,000 grape pickers.
The grapes are pressed, with only their juice collected during the process.
Care must be taken not to apply too much pressure, as this could result in the grape skins and their pigments coming into contact with the juice. From the 1840s, G.H.MUMM built press houses close to the vineyards, a practice that continued until around 1910. The company recognised that pressing the grapes soon after picking reduced the risk of damage from the long journey to the winery or from the weather. A whole year’s work in the vineyards could be lost all too easily.
Today, the House of G.H.MUMM still has seven traditional presses from that time, known as ‘Coquard presses’, near its vineyard holdings.
After pressing, the grape juice must have any organic residue, pips or skins from the grapes, and any vineyard soil removed. This is known as “racking”.
The grape juice is left in vats at a temperature of 10-15°C for about 16-18 hours. Any particles fall to the bottom by the action of gravity. The resulting clear juice, or “must”, is then moved to G.H.MUMM’s vinification vats.
1) Fermenting more than once
After pressing, the must is stored in vats for about two weeks at between 18°C and 20°C for the alcoholic fermentation process. Natural yeasts convert the sugar in the must into alcohol and carbon dioxide, turning the must into wine. G.H.MUMM is careful to keep the different crus and grape varieties apart, ensuring the character of each terroir is preserved until blending. The company has always allowed a second fermentation, known as the malolactic fermentation, to occur. This is a natural process during which the malic acid turns into lactic acid, reducing acidity and making the wines softer. This second fermentation is optional, rather than a requirement of the champagne appellation rules.
The malolactic fermentation directly affects the style of G.H.MUMM’s wines, leaving them softer without making them any less fresh or lively.
Following the fermentations, the wines are transferred to other vats to remove any remaining yeast or solids that could affect the taste. The wines are called "still wines" after clarifying, as they have yet to acquire their sparkle.
Blending involves the art of combining still wines of different grapes and growths to create champagnes of consistently high quality that reflect the house style of G.H.MUMM. This subtle art is considered the "signature" of any champagne house and its Chef de Caves. To reach the blending stage, around 2,000 samples are tasted, noted and memorised every year by Chef de Caves Didier Mariotti and his team of expert winemakers. Up to 77 different crus go into the Cordon Rouge blend each year.
To ensure G.H.MUMM's champagnes retain their usual depth and freshness year after year, reserve wines are carefully kept. These help soften any contrast between the different years’ wines during blending. In certain years when the harvest is exceptionally good, the Chef de Caves may decide to create a vintage, for which only wines of that year may be blended.
1) Bottle fermentation
The still wine becomes champagne while hidden in the depths of G.H.MUMM's cellars. The liqueur de tirage triggers a second alcoholic fermentation. Over the course of a month, at a constant temperature of 11°C, bubbles gradually form. This is how the wine becomes sparkling. Its alcoholic strength increases from 11% to 12%. The quality of this fermentation will determine how gentle the sparkle of G.H.MUMM's champagnes is, as well as their degree of freshness and depth. As the bubbles are formed, so the pressure inside the bottle increases, reaching as much as 6 bar.
The bottles are stored on their sides in G.H.MUMM’s cellars.
Dug by hand out of the chalk, these cellars comprise 25km of galleries in total, taking 70 years to excavate.
Today, they house nearly 25 million bottles.
Over many months, the wines develop their richness of taste and aromatic complexity. During the ageing process, the yeast forms a deposit in the bottle. It’s through contact with this deposit that the wine acquires its rich taste and distinctive character.
The winemaking team prefers to age the champagnes for longer than the legal minimum to create wines of perfect maturity. This means two and a half years for Cordon Rouge instead of eighteen months, and almost five years for vintage champagnes rather than three years. Another instance of the quality of G.H.MUMM champagne.
A liqueur de dosage, made from a mixture of cane sugar and old G.H.MUMM champagne, is added to the wine.
An integral part of the company’s expertise, the exact composition of the various formulas of liqueurs de dosage is a secret known only to the Chef de Caves. The proportion of sugar added dictates the style of champagne produced – Brut or Extra-Brut, Sec or Demi-Sec.
The liqueur used at G.H.MUMM is drier than most. At between 6g/l and 9g/l instead of the usual 12g for a Brut champagne, it allows the full subtlety of the blend to come through.
Finally, Didier Mariotti insists that all champagnes be left to rest before shipping, thereby letting the liqueur blend properly with the wine.