How do you cool a bottle of wine?

We decided to carry out a study using three traditional cooling methods as the fridge, the freezer and the ice bucket with water and ice, in the light of the general perception that white wines and sparkling wines suffer from sudden heat shocks. .

Is it better to cool a wine in the fridge, freezer or using ice bucket? Does the perception of a wine change if it cools in the fridge or ice bucket? Does the effervescence of a sparkling wine change if it cools in the freezer?

Introduction

At Vila Viniteca we have a Wine Tasting Panel — a private and unique initiative in the wine world — is formed of 16 professionals of our team, who we trained for two years, in order to become expert wine tasters. In March 2017, we started to train them so as to answer in an objective and faithful way to inquiries and doubts related to the sensorial perception, which are risen around a glass of wine.
As a result of this strict training of about 60 hours distributed in 2 years, it was possible to carry out what we were looking for: the objective sensorial analysis of a wine. Since then, in March 2019, our Tasting Panel started to carry out wine evaluation sessions to experiment our doubts.

Using the obtained data during these sessions, the sensorial profile of a wine can be carried out. The comparison of the obtained profiles from the samples, which are part of a project in the framework of a study, allows us to answer to a specific issue. One of the first issues we wanted to study was the cooling methods, in other words, how does it affect the manner of cooling a wine on its organoleptic perception? This is a common question that we find in our area from any point of view, both as a consumer or as a restaurateur. “I forgot to cool a bottle for the dinner. Does anything happen if I put it in the freezer? Do I preserve better the wine aromas if I cool it in the ice bucket? Or is it better if I cool it slowly in the fridge?”

The goal of this research project is to know how three different cooling methods influence on the same wine, analysing under the same criteria the obtained samples from each one.

We chose 4 wines to evaluate in this project. Two still white wines and two sparkling wines. The group of still wines is formed by a Xarel·lo from 2018 vintage of DO Catalunya with a 6 months of aging in French oak foudres of 2.500 L, and a Verdejo from 2018 vintage of DO Rueda vinified in stainless steel tanks and without aging. One of the selected sparkling wines is elaborated with the grape varieties Macabeu, Xarel·lo, Parellada and Chardonnay from 2015 vintage of DO Cava and with 30 months of maturation on lees, and the other one, a Champagne elaborated with Chardonnay, Pinot Noir and Meunier of different vintages and an 36 months of maturation on lees.

Methodology

These are the used conditions for this project:

All still white wines we evaluate them at a tasting temperature of between 6 and 8 ºC, and the sparkling wines, of between 4 and 5 ºC.

Used methodology to reach the tasting temperature of the still white wines between 6 and 8 ºC.

Fridge: a bottle of wine at room temperature (20 ºC) will be put vertically in a domestic fridge at 5-6ºC during 48 hours.

Freezer: a bottle of wine at room temperature (20 ºC) will be put horizontally in a domestic freezer during 48 minutes at -26 ºC

Ice bucket: a bottle of wine at room temperature (20 ºC) will be put vertically in an indivual ice bucket with 900 gr. of ice cubes and covered with water during 30 minutes.

Used methodology to reach the tasting temperature of the sparkling wines between 4 and 5 ºC:

Fridge: a bottle of wine at room temperature (20 ºC) will be put vertically in a domestic fridge at 5-6ºC during 48 hours and 30 minutes with water and ice.

Freezer: a bottle of wine at room temperature (20 ºC) will be put horizontally in a domestic freezer during 50 minutes at -26 ºC

Ice bucket: a bottle of wine at room temperature (20 ºC) will be put vertically in an individual ice bucket with 900 gr. of ice cubes and covered with water for 50 minutes.

The project was developed in 4 hours divided in three sessions in October 2019.

The panellists carried out the sessions in installations under the ISO 8589:2012 normative and they had 10 minutes to evaluate each glass individually with a green illumination to cancel the colour interferences.

Each panellist had to evaluate these characteristics of each sample:

Olfactive phase: (more information here)

  • The aroma intensity at still glass (continuous scale from 0 to 10): smelling ability of the wine without being moved
  • The aroma intensity at swirled glass (continuous scale from 0 to 10): smelling ability of the wine after being moved inside the glass.
  • Defects and intensity presence (light/average/intense) if any is detected: defect ability of being perceived as being smelled.
  • Aroma descriptors: the panellists have been trained to detect 48 aromas which can be found in a wine.

Taste phase (on the palate)

  • Sweet (continuous scale from 0 to 10). Wine ability of creating a soft and pleasant sensation on the palate as produced by honey or sugar. (More information here).
  • Acid (continuous scale from 0 to 10). Wine ability of creating a sour sensation or similar to lemon, pineapple or apple. (More information here).
  • Bitter (continuous scale from 0 to 10). Wine ability of creating a sensation similar to the quinine and alkaloids.
  • Alcohol sensation: wine ability to generate a warm, caustic or even abrasive sensation in the case it is not well integrated on the palate.
  • Alcohol integration (Yes:0 / No:1): wine ability of keeping in harmony the elements which compose it, in this case the alcohol.
  • Aroma intensity on the palate (continuous scale from 0 to 10): aroma ability of a wine to be perceived on the palate.
  • The global persistency of the detected aroma (continuous scale from 0 to 10): related to the ability of the wine aroma to remain latent, when it disappears from the palate.

Tactile sensations (on the palate): more information here

  • Astringency (continuous scale from 0 to 10): wine ability to trigger a roughness or dryness sensation on the tongue, teeth and gums. Sometimes it can produce a bitter sensation.
  • Fluidity (scale of 5 points: Low/Low-Medium/Medium/Medium-High/High): Wine ability to slide over the tongue. Friction and tactile sensation on the tongue and gums.
  • Volume (scale of 5 points): covering wine ability on the palate. Wine tactile sensation inside the mouth cavity. We can graphically imagine this as a sphere
  • Weight (scale of 5 points): wine ability to trigger a weight sensation over the tongue. We can graphically imagine this as what would fill the sphere. As heavier, more refilled is the sphere.
  • Silky mouthfeel (Yes: 0 / No: 1): wine ability to create a lubricaiting effect or greasiness sensation on the palate. Oily or greasy sensation which can be provided by nourishment in contact with the tongue surface, by releasing compounds which provide this sensation during the sip or after swallowing.

Specific methodology to evaluate sparkling wines

There have been identified two new characteristics related to the tactile sensations which the sparkling wines can provoke, and that until then the Panel had not worked: the effervescence and the bubble integration.

We understand by effervescence the carbon gas emission melted in the wine inside the mouth cavity. As richer it is, more intense we consider it.

Bubble integration: we understand it as the bubble capacity to create a smooth or creamy sensation on the palate. We analyse it according to the bubble perception generate it in the mouth cavity, if it creates a creamy sensation or by the contrary of roughness or aggressive sensation on the tongue or palate, being possible to become unpleasant. As more creamy sensation we have, higher will be the bubble integration.

We evaluate the two characteristics with intensity scales of 5 points (1 low sensation – 6 very intense sensation).

Results

Each wine sample was analysed for each panellist who evaluated it individually and rated the presence or intensity of each characteristic. An IT system collected all the data and after performing a statistic treatment, we obtained the results as average ratings, mentions percentages of presence and graphics.

It is important to remark that the presented results are only fruit of the resulting values of variance analysis and Tukey test. This analysis allows comparing values with the goal of determining if there are significant differences between them or not. Tukey test identify these particular significant differences and gives a validity percentage to each observed difference, the named confidence percentage. As higher is this percentage more accurate will be the conclusion. In our case, due to the fact we were searching for a good veracity of the extracted results, is minimum 90%. Any noted difference with an inferior percentage to this value was not considered.

Concerning the aromas, an analysis of the percentage of mentions of their presence has been done. In other words, from all the named aromas by the panellists have been taken into account those who had a mention superior to 15% over others.

I. STILL WINES

A – Xarel·lo 2018

Intensity and aroma persistence loss

Xarel·lo 2018 loses aroma persistency on the palate if it is cooled in the ice bucket. (*)

(*) It’s about the aroma persistency on the end of the mouth which varies significantly in view of 1 point over a scale of 10, regarding to other methods of the still wines.  We can claim it with a confidence percentage superior to 95%. (Figure 1)

Whereas, when it is cooled in the freezer shows a loss of its aroma intensity. (*)

(*) Aroma lavour intensity is lost both in still glass and swirled glass, regarding the other two cooling methods. We confirm it with a confidence percentage superior to 90%.

Figura 1

Different aroma types according to the cooling method

Xarel·lo 2018 has more presence of aromas belonging to the Green fruit family when it is cooled in the fridge, beyond the floral family and cooked fruit, both more present when it is cooled in the freezer.

When it is cooled in the ice bucket, the wine emits Tropical fruit notes, specifically of pineapple, and also of brioche.

B – Verdejo 2018

Different aroma types according to the cooling method.

The wine has less floral aromas when it was cooled in the freezer, however green fruit aroma as the apple and aromatic herbs are strengthen.

When the wine is cooled with ice bucket shows more aromas of stone fruit (peach), floral notes, citrus fruit (orange) and tropical fruit as pineapple and mango.

However, when they were cooled in the fridge appear more intense notes of tropical fruits (maracuyá), citrus (lemon), balsamic (eucalyptus), spices (nutmeg) and dry vegetal as tobacco.

Globally, from all mentioned aromas for the three methods, when the wine is cooled in the ice bucket more aromas appear. We can conclude that with this method the wine expresses more complexity and a wider variety of aromas. It is important to note that it is something which is not directly related to its intensity.

II. SPARKLING WINES

A – Cava Brut Nature 2015

  1. More intense bubble

When Cava Brut Nature 2015 is cooled in the freezer there is an inferior bubble integration than when it is cooled in the ice bucket. (*)

(*) The difference between both is of 0,5 points. We can claim it with a confidence percentage superior to 97%.

  1. Increase of alcohol sensation

Cava Brut Nature 2015 presents a superior alcohol sensation when it was cooled in the fridge, compared to the other two methods. (*)

(*) We confirm it with a confidence percentage superior to 90%.

  1. Less fluid, less bulky and with less weight

When it is cooled in the freezer experiments a loss of the tactile characteristics fluidity, volume and weight, especially if we compare it to the ice bucket. (*)

(*) We confirm it with a confidence percentage superior to 90%. (Figure 2).

Figura 2

Different aroma types according to the cooling method

If the sparkling wine was cooled in the freezer, there are more present the aromas from the cooked fruit family (cooked apple), citrus (lemon), green fruit (green apple), pastry (crumb) and dry fruits as bitter almond and nut.

When the sparkling wine was cooled in the ice bucket appear more pastry aromas (yeast or sourdough), earthy (mushroom) and citrus as the orange.

When it is cooled in the fridge the sparkling wine shows more aromas of aromatic herbs (thyme), lactic and toasts as coffee compared to other methods.

In this case, when Cava has been cooled in the freezer shows a higher aroma quantity, confirming that aromatically is the method which points out more complexity and wealth.

B –  Champagne Brut

Champagne, the wine which changes less according to the cooling method.

In all the characteristics comparisons that the Panel analyses there haven´t been found significant differences with the confidence percentage initially set (90%). For this reason, we can confirm that Champagne Brut is the product which less variability has experimented amongst the three cooling methods and, because of this, we can consider it as less variable.

Aroma presence variation according to the method

When the Champagne has cooled in the fridge shows aromas which reminds toasted as coffee, lactic notes, aromatic herbs as thyme and dry fruits.

If the sparkling wine has cooled in the freezer, it has more aromas of cooked fruit, citrus as lemon, earthy as mushroom and floral.

However, when it has been cooled in the ice bucket, green fruit (green apple), pastry (crumb), dry vegetal (tobacco), stone fruit (peach) and dry fruits as bitter almond and nut aromas are more present. We can conclude, in this case that the cooling of the wine in the ice bucket brings a major aroma richness compared to other methods.

To sum up

We have noted in case of still white wines that have been analysed that the different cooling methods affect the aromatic potential by increasing it or decreasing it.

In case of Xarel·lo 2018, when it was cooled in the ice bucket, the trend was to lose the aromatic persistency on the palate. Regarding its aroma intensity, in still glass or swirled glass, it can be noticed as reduced when it is cooled in the freezer.

In Verdejo 2018, we can observe an unexpected opposite trend, as its aroma intensity at still glass is increased when it is cooled in the freezer, beyond the other methods.

Regarding the results of sparkling wines, they focus more on the tactile sensations and we obtain significant differences in only one of them, Cava Brut Nature 2015.

In this one the bubble integration is affected when it is cooled in ice bucket, decreasing and as a consequence producing a more intense bubble sensation on the palate. On the other hand, its alcohol sensation becomes more patent when the wine was cooled in the fridge, phenomenon that does not happen for the other two evaluated methods. And finally, we have noted that when the wine is cooled in the freezer there is a loss of the tactile sensations fluidity, volume and weight regarding the obtained rates with the ice bucket method. Champagne Brut has resulted as the less variable product, because after the evaluation of the obtained results according to the previously mentioned statistic trials, we couldn´t extract any significant difference.

Conclusions

Even if someone thinks that the fridge is the most appropriate method to cool a white or sparkling wine, after our study there aren´t any significant and concluding evidences proving that this is the best method.  So much so that in some of the cases (as for Verdejo 2018), the aroma intensity is superior if the wine has been cooled in the freezer instead of the fridge. In contrast, Xarel·lo 2018 has decreased its aroma intensity in the freezer and the persistence on the palate in the ice bucket.

As for the sparkling wines, there are not clear evidences about which of the three methods is the most appropriate for the final quality of the wine. Champagne Brut remains more stable with the three methods without showing significant differences. Cava Brut Nature 2015 is more affected by the fast cooling of the freezer as the bubble integration, its fluidity, volume and weight is reduced. An idea that makes us consider that maybe another interesting project would be to study as the cooling method affects according to the doses.

Therefore, and contrary to our initial previsions or suppositions, we can conclude that we can cool a white wine bottle or a sparkling wine with any of three traditional methods (fridge, freezer and ice bucket) without experimenting a relevant alteration of the organoleptic qualities of the product.

The wines:

L’Equilibrista Blanc 2018

  • Wine cellar: Ca N’Estruc
  • Vintage: 2018
  • Variety: Xarel·lo
  • Wine making: aging during 6 months in French oak foudres of 2.500 L.
  • DO: Catalunya

El perro verde 2018

  • Wine cellar: El perro verde
  • Vintage: 2018
  • Variety: verdejo
  • Wine making: in stainles steel tanks and without aging
  • DO: Rueda

Aire de L’Origan Brut Nature 2015

  • Wine cellar: L’Origan
  • Vintage: 2015
  • Varieties: Xarel·lo, Macabeu, Parellada and Chardonnay
  • Wine making: minimum maturation on lees of 24 months
  • DO: Cava

Champagne Delamotte Brut

  • Wine cellar: Champagne Delamotte
  • Vintage: non-vintage (NV)
  • Varieties: Chardonnay, Pinot Noir and Meunier
  • Wine making: maturation on lees of more of 36 months
  • AOC: Champagne

*During the evaluations none of the panellists has had any explicit knowledge of the wines, service conditions, vintages, trials, varieties or any other information over the nature of the performed studies.

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