What is Grape Must?

When looking into the winemaking process, you might have encountered the term “grape must.” 

As one of the first steps, the must is incredibly important, as producing any wine without it is impossible.

If you’re unsure what this term means, don’t worry, we’ll explain everything. Keep reading to learn more about this vital winemaking component. 

Grape Must Definition

“Must” is a term used to describe the natural, freshly pressed grape juice that is eventually fermented and turned into wine. The must contains the seeds, stems, and skins of the grapes. These solid components are called “pomace,” which refers to separating the fruit skins from the juice. 

“Must” originates from the Latin word vinum mustum, which means “young wine.” When the grapes are just off the vine and crushed, there is no alcohol in the mixture, as the fermentation process has yet to begin. Concentrated grape must contain high glucose sugar levels, making it an excellent sweetener for other foods or wine. 

Must is very thick, and when left uncooked, the natural yeast will eventually trigger the fermentation process, transforming the natural sugars into alcohol. 

Now that you know more about must, let’s explore its role in winemaking. 

Grape Must in the Winemaking Process

Grape must is crucial in the winemaking process as it sets the tone for the final product. It determines many characteristics of the wine, such as color, alcohol content, and sugar levels.

Once picked from the vine, the grapes are washed and pressed until the juices and sugars have been wrung out. The grape skins, seeds, and stems (or pomace) are soaked in the must. This process is called “maceration,” the technical definition for soaking grape skins in the juice. 

Red wines that are darker in color result from a longer maceration process, whereas white wines and Rosé result from the wineskins having been in contact with the juice for a much shorter period of time.

Once done macerating, the grape skins (or pomace) are pressed once again to wring out any extra sugars and juice. The grape juice is then separated from the pomace and sifted into stainless steel vats, where it will begin the fermentation process. 

As mentioned earlier, a portion of the thick, unfermented grape must might be kept as a sweetener for the wine. Winemakers commonly refer to this natural sweetener as Süssreserve. The remaining pomace that is not part of the sweetener is usually tossed back into the vineyard and used as fertilizer.

Once in stainless steel vats, the juice sits at a controlled temperature. During this time, the natural yeast will begin converting organic sugars into alcohol. With many wines, especially dry wines, yeast will be added to speed up the fermentation process and eliminate any unwanted residual sugars that might be left behind. 

Before bottling, winemakers might add sugars or the Süssreserve if the desired outcome is a sweeter wine. 

With all this in mind, there is one last question regarding grape must that we need to address. We know the must is a natural, non-alcoholic juice that eventually becomes wine, but is it safe to drink before going through the process? 

Wine Fact: Did you know that grape must is one of the key ingredients for traditional balsamic vinegar?

Is Grape Must Safe to Drink?

Since wine must consists of natural grapes in their purest form, you might assume it’s safe to drink. In fact, some winemakers save a portion of pomace and add water to it, then let it sit, creating a more natural form of wine. The pomace can also be used to make brandy. 

Although grape must is a natural mixture, it is still raw and unpasteurized and will likely contain high amounts of pathogens or potentially unsafe bacteria. 

If you’d like to sample grape must in its purest form, we advise you to do so with the guidance of an experienced winemaker for the best and safest tasting experience. 

Grape Must is A Must!

As you can see, there is no fine wine without young wine first! Grape must is wine in its rawest, purest form before alcohol conversion kicks in. Therefore, when it comes to winemaking, grape must is a must and is a vital part of determining the characteristic of the final wine early on.

Now that you know more about the early parts of the winemaking process and what the juice that eventually becomes wine is called, head over to the Macy’s Wine Shop for customer-favorite red wines, white wines, Rosé, sparkling wines, and more.

Visit the Macy’s Insiders Blog for recipes and ideas from expert chefs and sommeliers, food pairing guides, wine regions, and varietals. 

Cultivate your wine love and knowledge today with Macy’s!