In the open-air laboratory of the Château Cazebonne winery, every gesture and every technical choice refines the grapes into wine—a true expression of our terroir and philosophy. Among these crucial stages, malolactic fermentation, often referred to by the acronym MLF, holds a key place. Far from being a simple "fermentation" in the yeast sense, it is a bacterial conversion with a profound influence on the final profile of our wines.

What is Malolactic Fermentation?

This microbiological process involves anaerobic bacteria that convert malic acid, which is naturally present in grape must and possesses a sharper, "greener" acidity, into lactic acid. This essential transformation results in a natural deacidification of the wine. The gain in roundness, suppleness, and complexity is significant, often accompanied by emerging buttery, milky, or brioche notes—characteristics that are particularly sought after in many styles of red and white wines. As Jean-Baptiste Duquesne highlights in his book "Bordeaux, une histoire de cépages", this transformation is one of the keys to understanding Bordeaux aroma profiles, where a balance between freshness and creaminess is pursued.

Objectives and Effects of MLF on Wine

The primary goal of MLF is to soften the perception of acidity in the wine. Malic acid has a harsher flavour profile, reminiscent of green apples, whereas lactic acid is softer and rounder, evoking milk. Beyond merely reducing acidity, MLF profoundly alters the sensory profile of the wine. It can foster the development of secondary and tertiary aromas, such as butter (diacetyl), toasted bread, or milky notes, thereby enhancing aromatic complexity. In terms of mouthfeel, winemaking with MLF generally imparts a creamier texture and greater roundness on the palate, which is often desirable for wines destined for extended ageing.

Timing of Malolactic Fermentation

Malolactic fermentation usually takes place after alcoholic fermentation, once the yeasts have converted most of the sugars into alcohol. However, in certain instances, it can occur simultaneously (co-inoculation) or be initiated earlier. The precise timing is a strategic decision for the winemaker, as it directly impacts the final style of the wine. Early MLF can integrate aromas more seamlessly, whilst late MLF can prove more challenging to control.

How Does MLF Take Place?

MLF is a natural process, but it can be initiated or arrested by the winemaker. Following alcoholic fermentation, the wines are often warm, which encourages the activity of naturally occurring lactic acid bacteria. If one wishes to trigger MLF, the wine can be inoculated with specific strains of lactic acid bacteria. If one wishes to prevent it, particularly to preserve the crisp freshness of lively white wines, techniques such as early sulphiting, sterile filtration, or temperature control (chilling) can be employed to inhibit bacterial activity.

Mastering MLF at Château Cazebonne

At Château Cazebonne, we approach malolactic fermentation with precision and discernment. We choose to carry it out on all our premier cuvées, whether white or red. This strategic decision allows us to refine the structure of our wines, soften any prominent tannins, and develop the complex aromas that define their distinctive depth and elegance. MLF softens the tannic structure of red wines and lends a creamy texture to the whites, thereby contributing to their ageing potential and tertiary aromatic complexity.

However, for some of our entry-level cuvées, particularly whites and rosés, we may choose to deliberately block MLF. This approach aims to preserve the vivid acidity, bright freshness, and primary fruit aromas of the grapes. These wines, intentionally crisper and more refreshing, are ideal for drinking in their youth, offering another facet of the Château Cazebonne experience. If you would like to learn more about the various techniques used, an article on white winemaking is available.

Château Cazebonne is actively committed to the richness and diversity of the Bordeaux vineyard, particularly by replanting ancient and almost forgotten grape varieties of the region. This work of championing our ampelographic heritage is an exciting challenge, made possible thanks to the unwavering trust and support of the many wine lovers who have embraced our wines and share our vision. To explore the rich history and the secrets of Bordeaux grape varieties through our book, feel free to download our work. You can also test your wine knowledge by taking part in our wine quizzes, or discover our exceptional cuvées directly in the Cazebonne online shop.