Microbial terroir plays a crucial role in the development of aroma compounds in wine. The unique combination of microorganisms present in the vineyard soil, on the grape skins, and in the winery can significantly influence the aromatic profile of the final wine product.
Microorganisms in the Vineyard
Microbial terroir starts in the vineyard, where a diverse community of microorganisms interact with the grapevines. These microorganisms include bacteria, fungi, and yeast, each contributing to the overall terroir of the vineyard. Some key ways in which microbial terroir influences aroma compound development include:
- Yeast Diversity: Different yeast strains present in the vineyard can impart unique aromatic characteristics to the grapes. For example, certain yeast species are known for producing fruity or floral aromas, while others may contribute earthy or spicy notes.
- Bacterial Influence: Bacteria present in the soil can affect the availability of nutrients to the grapevines, which in turn can impact the synthesis of aroma compounds in the grapes. Certain bacteria may also produce compounds that interact with grape metabolism and influence aroma development.
- Fungal Interactions: Fungi in the vineyard can interact with grapevines in various ways, such as promoting or inhibiting the growth of certain yeast species. These interactions can have a cascading effect on the microbial terroir and ultimately influence the aromatic profile of the grapes.
Microorganisms on Grape Skins
As grapes ripen on the vine, they come into contact with a multitude of microorganisms present on their skins. These microorganisms can play a significant role in shaping the aroma compounds that will be present in the resulting wine. Here are some ways in which microbial terroir on grape skins influences aroma development:
- Yeast Fermentation: The yeast present on grape skins are responsible for fermenting the sugars in the grapes into alcohol. During this process, yeast also produce volatile compounds that contribute to the aroma of the wine. The specific strains of yeast present on the grape skins can influence the types and amounts of aroma compounds produced.
- Fungal Infections: Fungi such as Botrytis cinerea, also known as noble rot, can infect grapes under certain conditions. While Botrytis can be detrimental to grape health, it can also lead to the production of unique aroma compounds in the resulting wine, such as honeyed or apricot notes.
- Bacteria Interactions: Bacteria present on grape skins can interact with yeast during fermentation, affecting the production of aroma compounds. Some bacteria may produce enzymes that release additional aroma precursors from the grape skins, leading to more complex aromatic profiles in the wine.
Microorganisms in the Winery
Once the grapes are harvested and brought to the winery, they continue to interact with microorganisms present in the winemaking environment. These microorganisms, along with winemaking practices, can further shape the aroma profile of the wine. Here’s how microbial terroir in the winery influences aroma compound development:
- Native Yeast Fermentation: Some winemakers choose to allow fermentation to occur spontaneously with the native yeast present in the winery environment. These native yeast strains can have a significant impact on the aroma compounds produced during fermentation, leading to a more unique and terroir-driven wine.
- Barrel Aging: Wooden barrels used for aging wine can harbor specific strains of yeast and bacteria that contribute to the development of aroma compounds. The porous nature of barrels allows for oxygen exchange, which can also influence aroma development in the wine.
- Temperature and Humidity: The environmental conditions in the winery, such as temperature and humidity, can impact the growth and activity of microorganisms. These factors can affect the rate of fermentation, the production of aroma compounds, and the overall aroma profile of the wine.
Overall Impact on Aroma Compounds
By considering the microbial terroir throughout the winemaking process, winemakers can harness the unique characteristics of their vineyard and winery environment to create wines with distinct aroma profiles. The interactions between microorganisms in the vineyard, on grape skins, and in the winery all contribute to the development of aroma compounds in wine.