The World of Wine Science

The World of Wine Science 

From botanical origins through microbial transformations to a product of global significance, there’s a whole lot of science behind a glass of wine. 

An introduction from A to V 

Archaeological records date wine back 5,000 to 7,000 years. Researchers have even made connections between written descriptions of ancient practices and ancient vineyards themselves, like one established in the volcanic soils of Pompeii, buried under ash in the eruption of Mount Vesuvius and then excavated in the late 1960s. 

Before modern technology came along, identifying and distinguishing vine varieties came down to sight and touch – a practice known as ampelography. Today, modern laboratory techniques make much more detailed studies possible. We’ll meet someone putting them into practice soon. 

Today, the species Vitis vinifera is the primary source of grapes destined for winemaking.  Its name even gets a nod in the term ‘viticulture’, which refers to the growing of grapevines. Oenology, on the other hand, is the study of wine production, fermentation and the many factors that influence flavour.  

After that taster of terminology, let’s now take a peek behind the scenes of grapes from vine to table. 

From botany to the bottle 

Though reportedly ‘small and unassuming’, the flowers of the wine-grape vine are fundamentally important. There’d be no grapes without them. Unlike many major agricultural crops today, they don’t rely on insects like bees for pollination. Instead, they typically self-pollinate. Each flower that is successfully pollinated will become a grape. 

By autumn, the fruit of grapevines is ripe and ready for harvest. While the fruit has quite an adventure ahead, for the vines it’s time for bed. With fruiting complete, they’ll drop their leaves and fall dormant for the winter months.  

Of the 77 million tonnes of grapes grown globally in 2024, just over 30 million tonnes were destined for wine. The first step for all this fruit is being separated out from stems and leaves, and this even has its own acronym. MOG, or any material other (than) grapes is discarded. The grapes are then crushed by being passed through special rollers or pressed up against a perforated wall. This process releases not only juice but enzymes that facilitate a process known as maceration – further breakdown that will add flavour. 

In the structure of a grape, the seeds, skin and pulp constitute the pomace. Compounds from this pomace released through maceration can have a big impact on the final wine. For white wine, maceration is kept to a minimum, but for red wine it’s prolonged. Tannins from the seeds and skin as well as anthocyanins all contribute to wines of deep red colour.  

Fermentation (or, officially, vinification) is the way in which grape juice gains its alcoholic qualities. This in turn is facilitated by yeast – a microbe you might recognise from bread baking or beer brewing. In the context of winemaking, the effects of different strains of yeast on the final product is an open area of research, including here in Australia. 

Although some grapes are ‘inoculated in the field’ with wild yeast strains, usual practice is controlled inoculation of the grape juice. The yeast feeds on the natural sugars in grapes and produces ethanol, according the wine its alcoholic properties and conveniently inhibiting the growth of other microbes – the ones that might spoil the final product. 

The eventual wine primarily consists of water and ethanol. The latter directly enhances sweetness and indirectly modifies perception of acidity. At high concentrations, it’s the ethanol that’s responsible for a burning sensation in the back of your throat.  

The ageing of wine occurs in two distinct stages: between fermentation and bottling, when oxygen is still available, and then after bottling, once oxygen has been excluded. Wine might be left in oak barrels to age, particularly if the winemaker wants to add extra flavour complexity. 

Wine to withstand worldly change  

In a world of changing environmental conditions, agriculture can be a challenging undertaking. From water scarcity and extreme temperatures, grapevine growing isn’t immune. 

What’s more, wine-grape vines aren’t your average agricultural crop. New vines aren’t usually grown from seeds. Instead, vine growers depend on grafting, using rootstock from one plant and the upper segment, known as a scion, from another. Like a minotaur with the head and torso of one kind and the body of another, a wine-grape vine is made of multiples.  

Grafting is a way to select for and optimise the qualities of an agricultural crop, but it relies on knowing what those qualities are. It’s here where we meet Dr Andres Zhou Tsang. 

Andres was born and raised in Spain and now resides in Adelaide. Through the course of his undergraduate degree in biology, his interest in genetics and genetic engineering was piqued – particularly by the prospect of ‘tinkering and making new things’. It was during a masters in biotechnology that Andres began looking at the salt tolerance of wild grapevines. As he knows and we’ll soon see, salt is more than a condiment.  

Looking to take his studies further (and, indeed, further afield) Andres took to googling PhD opportunities. What opportunities were out there for wine science around the world? So it was that he came across the ARC Training Centre for Innovative Wine Production, founded in 2013 and now hosting projects spanning the whole wine production process, from vine management to the microbial, chemical and sensory sciences. It was a perfect fit. 

Having made the move down under, Andres embarked on a PhD to study the genetics of the most resilient grapevines. 

Hot, dry weather doesn’t favour grapevines. Indeed, stressed vines tend to produce fruit of lesser quality and less of it overall. Moreover, certain irrigation strategies can lead to increasing concentrations of salt in the soil. This isn’t good for the plants themselves or the products we might make from them. 

Some vine varieties have developed ways to cope with very salty soils, though. One technique for looking into this involves breaking down leaf tissue, extracting DNA and then, making the most of modern technology, ‘reading the sequence of the genes’ to look for characteristics of resistance. Andres hopes such findings will inform the fate of not only wine-grape vines but agricultural crops around the world. 

Having completed his PhD, Andres continues to share his interest and expertise in wine science with students at Adelaide University. He remains committed to the science behind making sure wine is available for everyone, from thesis writers (he notes it helps!) to fine diners. For that, he and fellow scientists of wine certainly deserve a toast. 

References 

Carrasco, D., Zhou-Tsang, A., Rodriguez-Izquierdo, A., Ocete, R., Revilla, M. A., & Arroyo-García, R. (2022). Coastal Wild Grapevine Accession (Vitis vinifera L. ssp. sylvestris) Shows Distinct Late and Early Transcriptome Changes under Salt Stress in Comparison to Commercial Rootstock Richter 110. Plants, 11(20), 2688. https://doi.org/10.3390/plants11202688  

Daniel. (2023, September 25). Three glasses of wine are sitting on a table. [Photograph]. Unsplash. https://unsplash.com/photos/three-glasses-of-wine-are-sitting-on-a-table-5ZjqoPcL7sA 

GuildSomm. Ampelography: The Art of Vine Identification. 12 Oct. 2016, www.guildsomm.com/public_content/features/articles/b/guest_blog/posts/ampelography  

International Organisation of Vine and Wine. (2024). OIV Statistical Brief: Wine, Table Grapes & Dried Grapes in 2024. https://www.oiv.int/sites/default/files/documents/OIV_Statistical_Brief-Wine_Table_Grapes_and_Dried_Grapes_in_2024_0.pdf  

Jackson, R. S. (2008). Wine science: principles and applications. Academic Press. 

Li, M., Su, J., Yang, H., Feng, L., Wang, M., Xu, G., Shao, J., & Ma, C. (2023). Grape Tartaric Acid: Chemistry, Function, Metabolism, and Regulation. Horticulturae, 9(11), 1173. https://doi.org/10.3390/horticulturae9111173 

Mulhollem, J. (2025, July 22). Wine chemistry can be accurately judged from fermenting tiny batches of wine. PennState. https://www.psu.edu/news/research/story/wine-chemistry-can-be-accurately-judged-fermenting-tiny-batches-wine 

Tong, Hailey. (2025, January 8). Grapevine in a vineyard. [Photograph]. Unsplash. https://unsplash.com/photos/a-bunch-of-green-grapes-hanging-from-a-tree-cUUfx3I3RW0 

WSET Global. (2021, June 22). The lifecycle of a vine. Www.wsetglobal.com. https://www.wsetglobal.com/knowledge-centre/blog/2021/june/22/the-lifecycle-of-a-vine/