Because white grapes definitely ripen before red grapes, the first thing I was exposed to was definitely making white wine. Let’s see how white wine is refined and what each process means!
Explanation of technical terms
Grape Sorting (optional): When the grapes arrive at the winery, you can use a sorting table to remove some of the poor quality grapes and mixed stems through manual wine selection, or some precisely designed automatic systems to remove grains of unacceptable size, shape or color.
Grape crushing/de-stemming: Have you ever seen romantic scenes of grape stomping in some movies? They’re just doing a destructive job. Now, this gentle crushing effect on grapes can be achieved in other ways as well. Modern crushers often have a clogging function. Some wineries also tend to ferment whole grapes (unmilled) to preserve their flavor.
Whole bunches (optional): For sparkling wines, white wines made from red grape varieties and noble rot wines, the grapes are pressed directly from the whole bunch, without crushing and blocking. Nowadays, for high-end white wines, such as Chardonnay, many wineries also use whole bunch pressing to obtain good quality juice and to avoid bitterness ingestion.
Heat exchange treatment: In some hot regions, or when the vineyard is far from the winery, there is no guarantee that the grapes will arrive at the winery at a low temperature. The crushed juice mixture will be cooled to avoid/minimize yellowing (oxidation) of the juice during the pressing process.
Pressing: For white wines, pressing is done prior to the start of fermentation, usually using an airbag press. If the pressure is set too high, more bitter substances are introduced into the skins, stems and seeds.
Static tank/vessel: The main purpose of the press is to clarify the juice naturally. The juice will naturally rest in the tank/vessel for a period of time and the solids in it will naturally settle to the bottom by gravity, then the clear juice will be transferred to the fermentation tank to begin fermentation. It is important to note that solids are also a source of nutrients for yeast. If the juice is too clear, the yeast may not reproduce well during the fermentation process. In addition, some winemakers ferment turbid juice directly to enhance the structure and complexity of the wine. This is also a balancing act.
Fermentation tanks/barrels: Here the sugars in the must are converted to alcohol by the action of yeast. This is the core principle of winemaking. White wines are usually made in stainless steel fermenters or oak barrels. This process releases heat. Temperature control is critical to maintain the fruit flavors and aromas of white wines.
Aging of the mash/blending of the mash (optional): At the end of fermentation, dead yeast and other solids settle to the bottom of the vessel, collectively known as the mash. Keeping the wine in contact with the mud for weeks or even months helps to improve the complexity of the wine, giving it a nutty flavor and giving it better structure and texture (depending on the variety). These effects are further enhanced by stirring the mash to increase contact with the wine.
Malolactic-lactic fermentation (optional): This is the process of converting “sharp” malic acid into “soft” lactic acid. The winemaker can decide if this process is needed depending on the style of wine he wants.
Clarification (optional): This process can be accelerated by natural precipitation (resting) or filtration or by adding a new clarifier. The addition of clarifying agents can also improve the color stability of white wines and remove bitter tannins from red wines.
Aging (optional): Wine is a living liquid. Bottled wine is not the end of its life, but the beginning of a new one. Some high quality white and red wines develop more complex flavors with age. Of course, this is also related to the environment in which they are stored.
