We asked two winemakers, Nuno Martins Silva and Luis Gomes, to help us understand some of common techniques used in winemaking.
What is Malolactic Fermentation?
A malolactic Fermentation, more commonly known as MLF is the conversion of malic acid (think a green apple) into lactic acid (think a yogurt) and carbon dioxide. Since the former is a stronger acid than the latter, we can speak of natural de-acidification of wine. It is triggered by lactic bacteria existing in our wineries.
Do red wines and white wines go through it?
All wines with malic acid can trigger MLF, although it is more desirable in more acidic wines, particularly red wines from colder regions. Nuno, rejecting any form of absolutism, recognizes that in white wines it is less common than in red wines. When the producer or winemaker understands that it is not desired, MLF can be inhibited with the application of cold, SO2 or sterilizing filtration.
When tasting a wine, how can you tell it had malolactic fermentation?
During the MLF some volatile molecules are produced, namely diacetyl and acetoin, which results in the appearance of some milky and buttery notes. MLF reduces the acidity and brings with it roundness, body, and creaminess, i.e., they become rounder and smoother in the mouth.
What are the advantages and/or disadvantages?
The main advantage is the microbiological stability of the wine, eliminating the possibility of FML occurring in the bottle with consequent CO2 production, making the wine fizzy. It is also advantageous for overly acidic wines, making them rounder and smoother. When well conducted and adequate it can enhance the sensory matrix of the wine, increasing the aromatic complexity in both red and white wines.
For Luís, the main disadvantage is that it can make the wine less fresh and more "boring", especially in wines from warmer regions where the natural acidity of wines is already lower. Nuno adds that it can lead to eventual sensory deviations, and in wines that do not present attributes for MLF (particularly in whites, rosés, palhetes leads to one-dimensional wines from the tactile point of view.
How can you tell the difference from a white wine that had barrel aging versus malolactic fermentation?
Barrel aging (when it is of high quality) is widely used in the production of great wines around the world, due to the micro-oxygenation and the extraction of tannins and aromatic compounds provided by the barrels. In the opinion of the technicians, when the MLF occurs in barrels, it raises the wine to an even higher level, because there is a better integration of wood than when the wine is placed in barrels only after the completion of the MLF, resulting in more complex, harmonious wines with more layers.
In other words, the wood increases the wine's tactile three-dimensionality. By itself, MLF gives the wines lactic and buttery notes, while the barrel gives spicy notes such as vanilla, leather, and cedar, among others. Luís Gomes says that all the "Giz" red wines he produces in Bairrada make the full MLF in French oak barrels. Nuno points out that not all wines and wine styles can handle MLF.
Are there Portuguese regions that traditionally tend to use more Malolactic Fermentation than others? If yes, which ones?
The cooler regions are traditionally those where MLF is more common in white wines. Although there are producers who want to exalt the freshness of their wines, inhibiting MLF. It can be deduced that the regions of Vinho Verde, Bairrada, Lisbon, Beira Interior and Dão, where the acidity is more pronounced, will be those where one will find wines with MLF, while in warmer regions such as Alentejo and Douro it will be less common.
In red wines, MLF is still common practice in all Portuguese regions, although as a result of global warming, some producers are already inhibiting FML in some of their red wines.
With specific varieties? If so, which ones?
There are some varieties for which traditionally MLF is more common, such as Bical or the international variety Chardonnay. Others that are more aromatic, such as Maria Gomes or the international varieties Sauvignon Blanc and Riesling MLF is less frequent, in order to preserve their varietal identity.
Nuno adds that in theory, varieties with more acidity, and/or regions that enhance the acidity of certain varieties such as Arinto, Maria Gomes, Encruzado, Alvarinho and Síria would tend to use MLF more often.
White wines with MLF that Manuel Moreira recommends to try:
Comments