What factors affect wine quality the most? While grape quality and climate play a significant role, post-harvest winemaking techniques such as maceration, fermentation, extraction, and aging also influence wine flavors immensely. Last year I attended a special tasting dinner hosted by the owner of a winery in Red Mountain, Washington. Over dinner, we sampled a number of recent vintages from the estate, and the lead winemaker offered us in-depth insight into the winemaking techniques he uses to bring out the best flavors in the wine. From the estate’s use of extended bottle aging to help soften the tannins before release to his preference for warm fermentation after an especially cold growing season, we learned a great deal about how these processes affect the final quality and character of wine.
Aging and fermentation can have a major impact on the quality of a wine, but some winemaking techniques make a bigger difference in the final wine’s character than others. Understanding the factors affecting wine quality and flavor will help you understand why your favorite wines taste the way that they do and help you make better food pairing choices, allowing you to play to your wine’s strengths and fully enjoy the tasting experience.
How Maceration Impacts Red Wine Flavors
What makes red wine so much darker and more tannic than white wine? The answer is maceration. The maceration process is one of the most important factors affecting red wine quality because it has the greatest impact on the wine’s color and tannin level. Winemakers macerate grapes using one of two methods (though many variations of these techniques are also used):
- Traditional Maceration: During this process, winemakers lightly crush their grapes to release most of the juice and then let the pulpy mix (called the must) soak in the juice for a period of time. As the grape skins, seeds, and stems soak, they release tannins, flavor compounds, and pigment. Many winemakers heat the must in order to release more of these compounds into the wine and kickstart the fermentation process. This technique is usually only used for red wines, although some white varieties go through maceration in order to produce what are known as “orange” wines.
- Cold Soaking: This technique involves soaking freshly crushed grapes in a mix of water and sulfur dioxide. During cold maceration, winemakers keep the must at a low temperature in order to prevent the yeast in the wine from fermenting and producing alcohol. The longer the must soaks, the darker the wine will be. However, despite the dark coloration of the wine, this process actually extracts less tannin compared to traditional maceration. It’s similar to cold-brewing iced tea rather than making hot tea—iced tea tends to taste less bitter than hot tea because the cold water releases less of the bitter tannin in the tea leaves.
In addition to differences between types of maceration, the time the grapes spend in maceration also has an impact on the wine’s flavor. Even if a grape variety is grown in the same region and experienced the same growing conditions, a difference in maceration time can make them appear as if they’re two completely different varieties. The first time I tried a glass of Fullerton Pinot Noir from the Willamette Valley in Oregon, I would’ve guessed I was looking at a Syrah because the wine was so dark in color. This was because these wines undergo a prolonged maceration process—winemakers let the must sit for as long as 100 days.
And extended maceration time doesn’t just affect the color of the wine; it also impacts the flavor. Oregon winemaker Alex Fullerton explains that after the first few days of maceration, the wine becomes darker and more bitter due to the tannins in the grape skins. However, he adds that “At about two weeks into the [extended maceration] you start to notice a major shift as the wine turns a corner and softens up…the end result is a round, smooth, plush, polished, and complete tannin profile with a smoother mouthfeel.” This is why some winemakers choose to do an extended maceration when they craft their wines.
In the U.S., cold soaking has become more popular in the last few decades, especially for producers making Pinot Noir.
If you primarily purchase white wines, then maceration isn’t typically a major factor affecting wine quality because white wines rarely go through this process. However, if you buy much red wine, it can be revealing to research your favorite producers’ maceration techniques. Although this information is sometimes hard to come by, you can sometimes learn more about a producer’s techniques by attending a tasting or a winemaker dinner.
Cold-soaked wines are especially common among some traditional Burgundy producers, and this technique may result in a wine that has softer, more rounded tannins compared to similar wines made using traditional maceration techniques. In the U.S., cold soaking has become more popular in the last few decades, especially for producers making Pinot Noir. On the other hand, wines made using traditional maceration techniques tend to be more intense and require more aging to soften. Traditional maceration improves a wine’s aging potential by releasing more tannin from the grape skins and seeds due to heat exposure. While some cold-soaked wines can also age for decades, many lack the prominent tannin required for long-term aging.
Careful Fermentation Develops the Aroma of White Wine
Fermentation is one of the primary factors affecting wine quality and flavor characteristics, in particular, the aroma of white wines. White wines are heavily influenced by certain fermentation techniques because their aromas are more delicate than those of bolder red wines. A few years ago, I bought a bottle of Marlborough Sauvignon Blanc that I expected to be tart and refreshing with just a hint of green pepper on the nose. When I opened the bottle, I found that the wine tasted very tannic and had almost no aroma whatsoever. I later learned that this was because the winemaker had fermented the grapes at a higher temperature than usual. The grapes were slightly underripe that year, and as a result, the winemaker attempted to mask the vegetal aromas by extracting more tannin and flavor compounds during fermentation. Unfortunately, the wine had lost nearly all of its fragrance in the process. This is why many winemakers choose to avoid warm or hot fermentation when working with white wine varieties; they don’t want bitter tannin or other flavor compounds to overpower the wine’s subtle aromatics.
In general, the white wines that benefit most from longer skin contact and warmer fermentation are wines that naturally have well-developed aromatics.
To ensure that the aromatics are protected and given ample time to develop slowly, winemakers usually avoid extensive skin contact during the crushing process. Instead, many winemakers press the must out of the mix relatively quickly before fermentation begins. Later, during fermentation, the wine is exposed to cool temperatures, usually between 42 and 50 degrees Fahrenheit. This is just warm enough for the yeast to convert sugar into alcohol, yet it’s not so warm that the grapes release excess tannin or additional flavor compounds that would mask the more subtle aromas in white wines.
Learning about a producer’s fermentation techniques through special tasting events or by reading or listening to interviews with the winemaker can tell you a great deal about the character and quality of the white wine made by that producer. In general, the white wines that benefit most from longer skin contact and warmer fermentation are wines that naturally have well-developed aromatics. For example, Haut-Brion Blanc is known for its intense floral aromas, and in some cases, skin contact and warmer fermentation conditions can emphasize these. By contrast, Chardonnay typically doesn’t benefit at all from extensive skin contact or hot fermentation, since the variety isn’t especially aromatic to begin with; exposing Chardonnay juice to high temperatures during fermentation will release plenty of tannin without adding much complexity to the wine’s aromatics.
The ripeness of the white wine grapes can also determine which fermentation technique will be most effective. If the weather was especially cool or the grapes were underdeveloped, then hot fermentation and maceration can sometimes mask the bitter green notes in the underripe fruit. The problem with this technique is that it also covers up the wine’s other subtle flavors, resulting in an uninteresting, overly tannic bottling. The fermentation technique that the winery used and the vintage quality both contribute heavily to a wine’s aromatics.
Extraction Techniques Affect the Wine’s Intensity
Extraction techniques can affect quality and intensity in both red and white wines. After the grapes are crushed and the juice begins fermenting, winemakers stir the juice to extract even more flavor compounds. To accomplish this, they usually use one of two basic stirring techniques:
- Pump-Over: In a pump-over system, a pump circulates juice from the base of the fermentation tank to the top, exposing the wine to as much oxygen as possible in the process. This exposure to oxygen releases tannins and other flavor compounds in the wine. Wines that are exposed to a great deal of oxygen and wines that were stirred fairly aggressively tend to be more intense in flavor than wines that were stirred more gently or exposed to less oxygen. In this sense, you can compare the pump-over process to swirling your wine glass during a tasting—the more the wine is swirled, the more prominent the flavor compounds and aromatics are.
- Punch-Down: Not all wines benefit from a pump-over system. As with maceration and fermentation, the extraction process can overpower subtle flavors in delicate wines. A punch-down system tends to be more gentle than a pump-over system and is commonly used to develop the flavors of light-bodied wines. Winemakers using this technique carefully press down on the cap of berries and skins at the top of the fermentation tank. They generally do this by hand to ensure that the liquid isn’t agitated too aggressively. The goal is to minimize contact with oxygen, allowing the flavor compounds to develop naturally with minimal intervention. The result is often a wine that is less intense than that made from a pump-over system, however, that doesn’t mean that these wines lack complexity. Some winemakers choose a punch-down system because their grapes are fully ripe and the resulting wine is already naturally complex.
Neither extraction system is inherently better than the other. If your favorite wines are intense and very tannic, the producer may have used a pump-over technique to encourage these characteristics to develop. Likewise, if you tend to buy wines that are more delicate in structure or made with non-interventionist winemaking techniques, then these wines may have been made using a punch-down extraction process. Keep in mind that there are variations on both these techniques; a good winemaker can modify his or her extraction process to suit the grapes and the wine style, for instance, by using a gentle pump to circulate the juice without agitating the berries or clusters too much.
Aging Is One of the Biggest Factors Affecting Wine Quality
I grew up in a family of California winemakers who were loyal to local producers. Some of my earliest experiences with Chardonnay were oaked New-World styles from estates like Marcassin and Paul Hobbs, and as a result, I am used to associating Chardonnay with toasted, vanilla-heavy flavors. However, as I began exploring wine on my own as an adult and sampling Chardonnay offerings from around the world, I discovered that most of the flavors I had associated with Chardonnay actually came from the oak barrels, not from the grape.
Barrel- and bottle-aging techniques are significant factors affecting wine quality and their addition to the winemaking process can completely transform the flavor of the resulting wine. Some variables to consider when you buy wine for your collection include:
- Oak Aging: Most collectors already know that oak can add a woody flavor to wine, and, particularly in the case of American oak, a vanilla flavor. However, other contributions of oak include spicy, smoky, and caramel aromas, as well as lowered exposure to oxygen while the wine matures. Oak barrels ensure that very little of the wine comes into contact with oxygen, and this softens the resulting wine’s tannins.
- New vs. Old Oak Barrels: Just because a wine is oaked doesn’t mean it will taste the same as every other oaked wine. The age of the barrel can impact wine quality and flavors significantly. New oak barrels will add more flavor compounds to the wine than oak barrels that have already been used for multiple vintages. A wine aged in 100 percent new oak may taste too oaked for some palates, and may need aging time for the oak flavors to integrate into the wine’s structure.
- Types of Oak: The origin of the oak can also impact a wine’s flavor. French oak is very fine-grained, meaning that it usually incorporates oaked flavors into the wine slowly and subtly. Wines aged in French oak are a good choice if you prefer just a touch of nuttiness or spice that doesn’t overpower the grape variety or the terroir. Meanwhile, American oak has a medium grain, meaning that it adds much more flavor to a wine. Consider wines aged in American oak if you prefer bold, New-World styles or wines made from grapes, like Zinfandel, that can stand up to heavy oak flavors.
- Oak Toast Levels: Oak barrels are often toasted slightly to impart more flavor into the wine, and the toast level of a barrel impacts the wine’s quality in different ways. Light toasting adds earthy aromas and subtle wood flavors to the wine. A medium toast is usually used for wines that are slightly bolder in flavor, as the barrel imparts stronger flavors than a light toast. Medium-plus toasts impart even more oaked flavors than the medium toast and are typically used for wines that are rich and full-bodied. Finally, heavily toasted barrels produce wines that are smoky and have a flavor profile similar to a dark roast coffee. Barrels with a high toast level are used infrequently and only for the boldest red wines and for fortified wines and spirits.
- Steel Tanks and Concrete Vats: Crisp, fresh wines not meant to age in-bottle often age for a time in steel tanks or concrete vats. Unlike oak, steel and concrete containers don’t impact the flavor of the wine at all; these materials keep the wine under airtight storage conditions until it is ready to be bottled. If you’re looking for a fruit-forward, clean-tasting wine that is a great representation of the variety’s purest flavors, then look for producers that age their wine in steel or concrete.
The amount of time that a wine spends in barrels also has an impact on its aging potential. As the alcohol and water in the wine seep into the porous surface of the wood, the flavor compounds inside of the wine become more concentrated over time. This greater concentration—along with the addition of tannin from the oak itself—increases the wine’s age-worthiness. Moreover, even though the tannin in the wine is more concentrated, in the barrel it’s also able to integrate with the other flavor compounds over time, softening the wine. If you’re looking for an age-worthy wine that you can drink or resell decades later, it’s best to look for producers that use ample barrel aging and the highest-quality oak.
Factors Affecting Wine Quality: Which Winemaking Techniques Matter Most?
Each of the four main factors we talked about affect wine quality in different ways. Factors like hot fermentation and extended traditional maceration times can improve a wine’s aging potential and add a great deal of complexity and intensity to the wine. Meanwhile, producers that use steel tanks, punch-down extraction methods, cold soaking, and cold fermentation tend to produce young, crisp wines that are more delicate in flavor. As with everything in the wine world, however, winemaking techniques and their results are complex and there are numerous exceptions to these generalizations.
It’s also important to keep in mind that each grape variety responds differently to different winemaking techniques. That’s why, if you’re interested in a particular wine style or wines from a specific terroir, it can help to attend tasting events or winemaker dinners hosted by wineries. During these events, you should be able to learn more detailed information about the techniques that bring out the best characteristics in your favorite varieties, making it easier to identify wines that suit your collection and palate.
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