Pretty in Pink: A Story of Form Over Function

Why marketing aesthetics might be ruining the flavour of your Rosé

Rosé wine, though suffering from a relatively poor reputation, has had a tremendous surge in popularity over the past decade, and deservedly so. It has been transformed from a casual summer drink to a stylish and versatile option embraced by a much broader demographic, with an increasing appreciation for its ability to pair with food and its broad range of flavour profiles. I love a good glass of Rosé, but despite the increased market awareness of how good a drink it can be, I must admit to struggling to find examples on wine lists that are superior to similarly priced white wines. I suspect I know why that might be.

Let me ask you this: when was the last time you saw a bottle of Rosé in a dark bottle? Think about it. I bet it's been a while, and if you have, it was probably a rather expensive one. Though pretty, showing off how pink and fresh-looking the wine is, the clear bottles invariably used for the majority of Rosé wines expose the wine to what is known as light strike. If the wine has been exposed to light for a while, chances are the character of the wine will have degraded significantly from what the winemaker intended, and at worst may end up smelling like cabbage, drains, and wet dog. Not a particularly appealing prospect.

Rosé wines on shop shelves

You might think this is an extreme case, but the timeframe within which light strike can occur, in light conditions similar to those found in most supermarkets, is much shorter than you’d expect. This makes the problem much less of an edge case, but rather one that’s very likely affected most Rosé wines you’ve tried recently.

Before delving deeper into this topic, I'd like to thank MWs Susie Barrie and Peter Richards, who have done an amazing job covering this topic in their Wine Blast podcast, which is what brought this to my attention. I do, however, feel it warrants a closer look, particularly as it has such a severe, yet easily remedied, impact on the quality of Rosé wines available to us.

Why the clear bottles to begin with?

Though there is clear consensus that flint glass, or clear bottles, are generally less suitable for long-term storage, there are a couple of factors at play that prompt winemakers to decide on using them over conventional darker glass. Mainly, it comes down to marketing and consumer expectations.

In an interview with WineBusiness Monthly back in 2019, Randall Grahm, owner and winemaker of Bonny Doon Vineyard in Santa Cruz, California, explained that while potentially damaging to the wine, not using flint glass for pink wine is a commercial risk that anyone with sufficient volume to sell can’t take. The majority of Rosé drinkers not only expect their pink drink to be visible from the bottle, but prefer it: part of Rosé’s aesthetic is the visual aspect of the bottle on the table—the wine is a feature in and of itself.

“I think that if you’re selling wine through the wholesale channel and you have a fairly good-sized quantity of wine to sell, you more or less have to just bite the bullet and use flint glass if you’re selling pink wine,” - Randal Grahm

Taking a quick look at any U.K. supermarket shelf that has Rosé wines on display confirms that this very much remains the case. I’ve not seen a single still Rosé wine on the shelves anywhere that was not in a clear bottle.

Unfortunately, the reasoning behind it does appear to be rational from a commercial perspective, at least going by the results of a survey conducted among 838 consumers who were asked to pick their preference of Rosé based on a visual aid presented to them to assess the hue they preferred and how it translates into what they expect from the bottle. They were shown six images that depicted glasses of Rosé, which tended toward either pink or salmon in colour and ranged from light to dark hues of each colour.

According to the results, more than half (54 percent) of participants perceived the darkest-hued pink wine to be the sweetest; dark salmon wine, followed by dark pink wine, were perceived as the most robust in flavour (45 percent and 37 percent, respectively). Those who said they preferred a drier Rosé (32 percent) were more than twice as likely to have purchase interest in the lightest pink Rosé and six times as likely to have interest in buying the darkest salmon-coloured Rosé versus those who said they prefer a sweeter style (66 percent). Those who prefer a sweeter style were more likely to have purchase interest in the darkest pink wine.

This shows there’s a clear notion among regular consumers that the colour of a Rosé wine matters, to the point where the colour, as much as the quality of the wine, effectively dictates the purchasing decision.

Aren’t they pretty?

In a sense, I find this to be quite curious. Regular consumers of red and white wines, while maybe paying some attention to the colour in the glass, do not make the same, erroneous quality assessment based on colour. I don’t, however, think it’s necessarily just an educational issue that holds back the use of darker-coloured glass for Rosé wines, but rather the fact that not showcasing the pretty pink hues would represent a break with the “Rosé all day” image this style of wine has developed over the years.

What I said earlier with regard to its reputation was in reference to the quality of the wine, but I believe the social construct which paints Rosé wine as a “girly” drink is alive and well and making itself felt. Indeed, around 40% of consumers of Rosé wines are women between the ages of 21 and 34, which may partially drive the particular aesthetics underpinning the need for pretty pink bottles. There’s nothing wrong with this, of course, aside from the fact that most will never have tried a Rosé wine that lives up to its true potential, in part as a consequence of this unspoken consensus that pink wine has to come in clear, and sometimes quite fanciful, bottles.

Flint glass is also increasingly popular in white and orange wines, particularly more natural-leaning examples.

What happens when the wine is exposed to light?

So what’s the big deal? Most wine currently sold in flint glass bottles is, after all, not intended for any meaningful long-term storage, with around 90 percent of Rosé wines from Provence (as an example) being consumed within the first year following the harvest. The problem is, as S. Carlin et al. explain in their 2022 article Flint glass bottles cause white wine aroma identity degradation, significant degradation of the quality of a wine, and its varietal identity, can occur after as little of 7 days in the bottle under regular supermarket conditions.

The research paper linked above is excellent and contains a tremendous amount of detail regarding the specific compounds affected, should you wish to delve deeply into the chemistry.

To summarise some of the key findings, however, UV radiation and light in the visible spectrum can trigger several photochemical reactions, such as photo-oxidation, isomerisation, hydrogen abstraction and addition, cycloaddition, and polymerisation of a variety of volatile compounds associated with well-known aroma characteristics in wine. In particular, so-called primary volatiles, such as terpenes and norisoprenoids, are key to the characterisation of the identity of a given cultivar.

In an experiment designed to mimic supermarket shelf conditions, the study found a clear relationship between the amount of light permitted to interact with the wine and the extent to which there was a loss of what can be called chemical identity. The control bottles, stored at 4°C in complete darkness, of course, were not affected, but green bottles showed a partial loss, while the wine stored in clear flint glass bottles was so degraded as to completely erase varietal differences, making it chemically impossible to distinguish the Pinot Gris and the Chardonnay after a period of only two months. In essence, the resulting wines are at best described as generic white wine.

Single time point experiment based on 20 wines coming from four cultivars. Results after two months.

Norisoprenoids, which include metabolites such as β-damascenone, β-ionone, and TDN (1,1,6-trimethyl-1,2-dihydronaphthalene), are critical to several aroma descriptors. The study looked at the impact on two isomers of β-damascenone, which were described as having different odour descriptors, such as baked apple, quince, and floral, depending on their concentration and on the matrix, with a very low sensory threshold.

Reduction of cis-β-damascenone over time under supermarket lighting conditions

For the Pinot Gris wines bottled in flint glass, the average loss of cis-β-damascenone was 34% after 2 days and 65% after 7 days. For the same storage period (2 to 7 days) in coloured glass bottles, the loss was negligible and was around 40% only after 50 days. Therefore, the damage caused by light passing through flint glass after 2 days was comparable to that in coloured glass after 50 days. Similar results were observed for the Chardonnay, which goes to show just how rapidly the wine can degrade.

With regards to terpenes, compounds which react with acids produced during alcoholic fermentation, resulting in acetate esters, the results are just as shocking. These acetate esters are also molecules associated with positive aroma characters and are responsible for much of a wine’s secondary aromatic profile.

In fact, with such rapid degradation, it is very likely that whatever clear glass-bottled white or rosé wine you purchase in the supermarket will be impacted by this to some degree.

The problem is not limited to the specific aroma compounds of the terpenes and norisoprenoids that are broken down either. β-damascenone, for instance, also accentuates and enhances other positive aroma compounds in wine, further exacerbating the loss of character.

Furthermore, as the positive aromas are degraded and muted, off-smells otherwise too subtle to be detected become more prominent, leading to not-so-charming notes of wet dog or boiled cabbage coming forward, as well as sulphur-containing compounds like dimethyl sulphide.

It should also be noted that these problems are cumulative and non-reversible. Once affected by light strike, those aroma compounds cannot regenerate. That means that even relatively careful handling, if over a sufficiently long period, can compromise the wine. As mentioned above, most Rosé wines are intended to be drunk within the first year of production, but as we’ve seen, that is an enormous amount of time during which things can go wrong, and this would be very much mitigated by using a dark-coloured bottle.

The Scale of the Problem

So how prevalent is this problem? The evidence for that is a bit more anecdotal, but based on the experiences of Liz Gabay MW and Panagiotis Arapitsas, co-author of the above-referenced paper, both quoted in the podcast episode by Susie and Peter, around 30-80% of wines in clear glass are affected. Proper testing would, of course, be required to give a more statistically relevant figure, but it is clear that this is not a trivial problem.

While we're mainly talking about Rosé wines here, the category probably most affected due to consumers’ perceived need to see the colour of the wine, it certainly affects white and sparkling wines as well. Red wines are somewhat more resistant due to the presence of higher concentrations of polyphenols, but given sufficient exposure to the right wavelengths, they would not be immune either.

Final Thoughts

So where does that leave us? Can the minority of us now aware of this issue make sufficient noise to shift broader consumer trends? Personally, I’m not convinced we can. I do, however, applaud producers who take the commercial risk of bottling their wines appropriately, giving consumers the opportunity to taste what their wines are supposed to taste like.

It is unfortunate, however, that we cannot trust the wine we order in restaurants and wine bars not to be affected by this. Sometimes the occasion calls for Rosé, but more often than not, what you get is a disappointment. You get a wine that’s a muted shadow of its true self. It’s so prevalent that I suspect a fairly large portion of regular Rosé consumers will, to some extent, have come to associate the effects of light strike with the drink itself, not realising it’s a taint.

I, for one, will probably suppress my Rosé urges and just get a white wine instead the next time I’m in a wine bar…

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Possibly Useful Post-Script

The list below represents winemakers that have said enough is enough, and have bottled their Rosé in conventional, dark glass bottles.

• Johannes Zillinger – Numen, 2021, Lower Austria, Weinviertel

• Dominio del Águila – Peñas Aladas Clarete, 2020, Castilla y Leon, Ribera del Duero DOC

• Clos Cibonne – Cuvée Prestige Caroline, 2021, Provence-Côte d'Azur, Côtes de Provence AOP

• Château Pesquié – Quintessence, 2021, Rhône, Côtes de Ventoux AOP

• Château Saint-Esprit - Famille Croce-Spinelli – Quintessence, 2022, Provence-Côte d'Azur, Côtes de Provence AOP

• Weingut Georg Weinwurm – Hommage – Roter Muskateller, 2022, Lower Austria, Weinviertel

• Filarole – Onda d’urto Rosato, 2022, Emilia-Romagna, Piacenza

• Château de Manissy – Tête de Cuvée, 2021, Rhône, Tavel AOP

• Ktima Kir Yianni – Agathoto, 2021, Macedonia, Naoussa OPAP

• Famille Fabre, Château Fabre Gasparets – Les Amouries, 2019, Languedoc-Roussillon, Corbières AOP

While I cannot guarantee the quality of these wines, they represent a good starting point when exploring Rosé wines that are not marred by flint bottles.