Analyzing the Compounds that Influence Foamability and Foam Stability in Sparkling Wines

Happy New Year! I hope the first week of 2015 has treated you all well so far, and if not, well, it’ll get better!

Since it is the New Year, and since sparkling wine is the traditional go-to wine for this particular holiday, I thought I’d share with you the results of a new study examining the major players in making and

maintaining foam in the top of your glass of bubbly! This particular study gets pretty heavy into the physical chemistry of the foamability and stability of foam in sparkling wine, though in this post I will provide a more simple analysis and touch on the major highlights from the research.

**If you are really into physical chemistry and would like to learn more about exactly how the components of sparkling wine act to create and maintain foam, please let me know and if there is enough interest, I’ll do a more in-depth follow-up piece.**

Research into the foamability and stability of sparkling wine is somewhat inconclusive in the scientific literature. While there may be studies here and there on certain aspects of foamability and stability of foam in sparkling wine, most studies only use “model” wine (i.e. not an actual wine off the shelf) and only focus on one or an otherwise small number of component in the wine that may be playing a role. Even within these limited studies, results are often contradictory and it is unclear from the current set of research what exactly influences foamability and stability of foam in sparkling wine.

Most, if not all, of us know that the bubbles in sparkling wines come from the CO₂ that is trapped in the wine after undergoing a closed secondary fermentation (in the bottle for those wines make under the traditional or champenoise method). What is not known with any certainty is what is it that allows the wine to foam up when being poured out of the bottle, and what allows the foam to maintain a nice, tight hold without immediately fizzing away to nothing. Some studies have implicated proteins as playing a role, while others have implicated peptides, polysaccharides, and polyphenols, though results have been contradictory.

A new study, published in the journal Food Chemistry, aimed to address these questions by determining the influence of several wine components in the foamability and stability of foam in sparkling wines. Specifically, they looked at free amino acids, biogenic amines, proanthocyanins, hydroxycinnamic acids,

flavan-3-ols, flavonols, and polysaccharide families.

Brief Methods

All sparkling wines (both wine and rosé) were made using the same winemaking conditions (traditional champenoise method) for three consecutive vintages. All wines were made at the Instituto Tecnológico Agrario de Castilla y León in Spain. Wine samples were taken after they had been on the lees for 9 months. Wines were then riddled, disgorged, and supplemented with liqueur d’expédition. Samples from 3 bottles were taken at each of the disgorging times during the 3 consecutive vintages (2009, 2010, 2011).

For each wine sample, foamability and foam stability were measured and analyzed. Free amino acids, biogenic amines, proanthocyanins, hydroxycinnamic acids, flavan-3-ols, flavonols, and polysaccharide families were also measured and analyzed for each wine sample.

 

Results

General Composition and Trends:

• Total phenolics did not play a role in foamability or foam stability (but the individual compounds did…)
• Monomeric anthocyanins were highly (positively) correlated with the foamability of sparkling wines (so, the more anthocyanins present, the better the foamability).
• All anthocyanins played some role in foamability, though none of them influenced foam stability.
• Within the anthocyanins, the highest positively correlated compounds with foamability of sparkling wines were (in order of correlation, highest to lowest): non-acetylated anthocyanins, acetyl-glucoside anthocyanins, and coumaroyl glucoside anthocyanins.
• Total proanthocyanidins were negatively correlated with the foamability of sparkling wine (so the more proanthocyanidins present, the crappier the foamability).
• Total hydroxycinnamic acids and total flavonols had no influence on foamability or foam stability of sparkling wines (though individual compounds did….see below).
• Total amino acids were highly (positively) correlated with the foamability of sparkling wines (so, the more amino acids present, the better the foamability).
• Biogenic amines were positively correlated with the foamability of sparkling wines, though not as strongly as total amino acids.
• Total polysaccharides were the only group of compounds that influenced foam stability in the sparkling wines tested, and were also shown to have NO influence on foamability of those wines.
• All polysaccharides analyzed were correlated with foam stability in sparkling wines, with grape polysaccharides having a greater influence than yeast polysaccharides.

Individual Phenolic Compounds:

• Cis-caftaric acid was negatively correlated with foamability of sparkling wines.
• Coumaric acid, gallic acid, and isorhamnetin were positively correlated with foamability of sparkling wines.
• Catechin and quercetin were somewhat positively correlated with foamability of sparkling wines.

Individual Amino Acids and Biogenic Amines:

• Glycine, β-alanine, and methionine were the most highly correlated (positive) amino acids with foamability of sparkling wines.
• Amino acids with non-polar side chain structures were more highly correlated with foamability than amino acids with polar side chain structures.

Polysaccharide Familes:

• Recall: polysaccharides were the only compounds found to influence stability of foam in sparkling wines, while they did not play a role at all in the foamability of the same wines.
• Those polysaccharides that were rich in arabinose and galactose were found to be the most highly correlated (positive) polysaccharides with stability of foam in sparkling wines.

Conclusions

The results of this study indicate that foamability and stability of that foam in sparkling wines is a complicated beast. There isn’t one compound or group of compounds that is responsible for making and keeping good quality foam. Instead, it is a synergistic relationship between many different compounds that when acting together result in the foam you see in your glass of bubbles.

According to the study, it appears that there are many different compounds that influence the foamability of sparkling wines, though only polysaccharides seem to be responsible for keeping that foam up and stable.

Through various structural elements, charge interactions, and seemingly complicated physical chemistry reactions, various phenolic compounds, amino acids, biogenic amines, and polysaccharides all work together to produce and maintain the quality of foam in sparkling wines.

Additionally, there are hundreds, if not thousands, of compounds in wine that have not yet been identified. Do these compounds play a role in the foamability and stability of foam in sparkling wines? My guess is probably—in a similar synergistic effect as those known compounds already analyzed.

Because of the large number of known and unknown individual compounds that can influence the foamability and stability of foam in sparkling wines, an equation to calculate this influence is extremely complicated. Instead, understanding general trends (see above) can help winemakers create a sparkling wine with higher quality foam characteristics, and ultimately a more desirable product to put on the market.

In summary, it’s complicated, so enjoy that bubbly before your head explodes thinking about these complex interactions.

If you have any questions, comments, etc., please feel free to leave your comments! Cheers!

Source:

Martínez-Lapuente, L., Guadalupe, Z., Ayestarán, B., and Pérez-Magariño, S. 2015. Role of major wine constituents in the foam properties of white and rosé sparkling wines. Food Chemistry 174: 330-338.