The Impact of Vibration from Three Perspectives | How Does Vibration Change Wine?

Once bottled and shipped from wineries, wines are influenced by various environmental factors that alter their taste. We describe these taste changes as aging or deterioration. When we think of wine aging or deterioration, oxidation and heat damage are likely the first factors that come to mind.

The five factors that influence wine are:

• Temperature
• Vibration
• Oxygen
• Humidity
• Ultraviolet light

Among these, temperature is considered to have the greatest impact.

However, it is well-known that contact with oxygen causes oxidation, sometimes ruining both the taste and aroma of wine. Changes in humidity lead to cork drying and liquid leakage, as well as mold growth. While ultraviolet light is protected against by bottles, its impact would be severe without such protection.

Several factors, including temperature, affect wine not only individually but also as combined factors working together.

Among these factors, there is one that influences wine only under limited conditions: vibration.

Vibration is a factor that is primarily considered only during wine transportation. Because its impact occurs in limited situations, there are few research studies examining its effects in isolation, and the definitive scope of its influence has not yet been clearly established.

Today, we examine vibration—an unknown factor that changes wine.

Does Vibration Change Wine?

The degree of impact that vibration has on wine varies according to different research studies. Some studies conclude that vibration does not affect wine's taste or aroma, while others report that wine does undergo changes. This difference comes down to the magnitude and duration of vibration.

When we speak of vibration, if we were to shake a wine bottle vigorously, the wine's taste and aroma would certainly change. However, this can be attributed to the release of dissolved carbon dioxide from the wine and increased contact with oxygen inside the bottle due to the extremely intense vibration applied.

In other words, this cannot be considered a pure effect of vibration. Moreover, subjecting wine bottles to such treatment is extremely rare.

Therefore, we are focusing on vibrations of the magnitude that occur during transportation.

Looking at multiple research studies, cases where the duration is limited to short periods of about one month or less show no effects significant enough to be considered statistically meaningful. On the other hand, when vibration continues for several months, significant differences begin to appear in wine's taste and aroma.

This means that wine can potentially be changed by vibration. However, a certain duration is simultaneously required for this to occur.

Below, we will examine the effects of vibration on wine from three perspectives: acidity, appearance, and aroma.

Acidity | Effects on Acid Content and pH

Several factors have been identified as elements through which wine is affected by vibration. One of these is acid content.

In studies conducted continuously for up to 18 months with varying vibration intensities, pH was found to be a factor that is either difficult to influence or almost unaffected. However, changes were observed in the acid content of wine. Very interestingly, tartaric acid content slightly increased up to a certain period, then decreased thereafter.

This change was also accompanied by decreases in some organic acid content, and the degree of impact was related to vibration intensity.

It should be noted that in cases where the decrease in tartaric acid content was greatest, changes in pH values were also confirmed.

It is well-known that acid levels drop as wine ages.

This means that vibration likely accelerates wine aging. Moreover, the degree of this impact is so significant that it can compress changes that normally occur over years or even decades into just a few months.

Appearance | Vibration Makes Wine Cloudy

In most cases, cloudy wine is judged to have quality defects. For this reason, many winemakers use filters to clarify wine before bottling, finishing the wine as a beautifully clear liquid.

On the other hand, it has been pointed out that vibration may render such winemakers' efforts futile. Vibration can potentially make wine cloudy.

According to the results of the aforementioned research, wines subjected to vibration showed increases in refractive index over short periods. Multiple factors have been identified as causes of refractive index changes, including changes in phenolic content.

While this study did not clearly confirm the impact of phenolic content changes on wine color, it has been pointed out that vibration may potentially affect the color of wine, particularly red wine, as one possible outcome.

Aroma | Changes in Wine Aroma

Wine aroma is largely composed of alcohols, acids, and esters. Among these, alcohols and esters account for more than 90% of the free volatile components contained in wine, and most of wine's aroma is provided by these compounds.

The most abundantly contained compounds are those classified as higher alcohols. The content of these higher alcohols has been reported in previous studies to show no significant changes during wine aging processes.

This means that while there may be possibilities of alteration due to oxidation, aging does not have a major direct impact on the quantity of aromatic components. Changes in the content of aromatic compounds affect the composition of aroma itself rather than the intensity of aroma, making this point important.

In contrast, it has been suggested that vibration may cause changes in their content.

As mentioned earlier, when the content of various components that constitute aroma changes, their respective composition ratios change, potentially fundamentally altering wine's aroma and flavor. This represents a problem that could be fatal when considering wine quality.

Summary | Can Vibration-Induced Aging Be Utilized?

Sometimes wine requires a very long time to reach its optimal drinking period. We occasionally hear stories of wines from vintages decades old that still have not reached their peak drinking time.

If we can patiently wait for our bottles to reach their optimal drinking period, that would be ideal. However, the situation changes when dealing with bottles that might not reach their peak during our lifetime.

After all, we want to enjoy bottles we have acquired ourselves. Attempts to successfully age wine in short periods are constantly being made.

One such attempt involves applying vibration.

Methods of applying vibration range from using ultrasonic vibrators to placing wine in locations where vibration is constantly applied, such as at sea or beside railway tracks. Certainly, by applying appropriate vibration to wine through such means, it is possible to accelerate some aging processes and reach the wine's optimal drinking period without waiting for long periods.

On the other hand, vibration-induced acceleration of wine aging has poor reproducibility and is an extremely difficult technique to manage properly. Additionally, it has been pointed out that aging through this method may result in component compositions different from normal aging. This means that risks of undesirable aging results constantly exist, and with high probability.

Based on these considerations, vibration-induced acceleration of wine aging cannot be considered a desirable method, and it is preferable that wine be transported and stored while avoiding vibration as much as possible.