Dear Sommelier, - The Australian Sémillon: A pioneer now cast in a supporting role

Good morning! This week we’re looking at Australia🇦🇺

We are continuing our tour of English-speaking countries, but this time we’ve moved on to Australia🐨

Since we’re studying in alphabetical order, after "E" for England, we have "A" for Australia. But interestingly, the history of Australian wine actually began with England! What a coincidence.

It all started in 1788, when Captain Arthur Phillip (the first Governor of New South Wales, Australia’s first colony) brought white grape varieties like **"Semillon"** to Sydney.

It seems that on his way to Sydney, the Captain stopped in Cape Town, South Africa, and realized, "Grape cultivation and wine production are successful here!" prompting him to try the same in Australia.

At the time, Australia was a penal colony for British convicts, but rather than producing wine just for them to drink, it was a choice made with an eye toward self-sufficiency and future export industries.

While it seems other grapes were brought over in addition to "Semillon," they were mostly white grapes. Has this historical beginning carried over into Australia’s current viticulture?

Upon researching, the answer is no. The ratio of black grapes to white grapes is 6.5:3.5. While this is quite balanced compared to Uruguay (8:2) or New Zealand (2:8), black grapes are dominant.

The most widely planted variety is the black grape **"Shiraz," accounting for about 34.19% of the total.** Meanwhile, the first grape introduced, **"Semillon,"** ranks third among white grapes at only about 4.27%.

Why is it that the grape introduced first is now a supporting actor, while another emerged later to take center stage?

Why couldn't "Semillon" take the crown?

The likely reasons are difficulties in supply (= hard to grow) and a mismatch with market demand. Let's look at each!

■ Difficulty in supply: Was Semillon hard to grow in the Australian climate?

Australia is a vast country (about 20 times the size of Japan), so when we say "Australia," the climate varies significantly by region. Grapes are primarily grown in six states; for example, South Australia has areas that are hot and dry, as well as areas that are cool and humid.

What is the ideal environment for Semillon?

・Temperature: About **20°C to 30°C** is just right. Because it has thin skins, it can get sunburned if it’s any hotter, and it’s susceptible to frost damage if it’s too cold. Considering Japan's climate, it would be difficult to cultivate in areas with extreme summer heat or harsh winters.

・Humidity: Semillon has a "dual nature." It is sensitive to water shortages, yet high humidity increases the risk of mold and rot. It's as if the grape is saying, "I want water, but I don't want to get wet."

While irrigation technology is used to manage water in Australia's arid regions, disease control is a major concern in high-humidity environments like Japan's rainy season.

Soil: It prefers well-draining sandy loam or clay loam soil. While sensitive to lack of moisture, the risk of rot is even higher, so soil with high water retention is not suitable. Its survival strategy involves extending its roots deep underground to extract water.

What is an early-ripening variety?

Semillon accumulates sugar rapidly within the fruit, meaning it reaches peak harvest time early. Because its acidity also decreases rapidly, it must be harvested early to maintain proper balance.

Looking at it this way, I feel like Semillon is a "delicate but stubborn" grape.

In Australia as a whole:

・It is difficult to standardize climatic conditions.

・Irrigation technology and disease control require cost and effort.

・As an early-ripening variety, the harvest window is short, making it difficult to judge the timing.

These reasons combined meant that Semillon was destined for a decrease in production.

■ Mismatch with market demand

Due to the rise of Chardonnay and Sauvignon Blanc, demand for Semillon has become relatively low. There is a strong preference for fresh and fruity white wines, and these varieties are favored for their immediacy and accessibility. Conversely, Semillon is a variety that shows its true value through aging. This market mismatch has led to an overall decline for Semillon. However, in specific regions, it continues to demonstrate its uniqueness as an age-worthy wine. What kind of regions are those?

Where is Semillon cultivation successful?

・New South Wales (Hunter Valley) 

A region located north of Sydney. (Captain Phillip's intuition was spot on!)

Hunter Valley is a region with high humidity and significant summer rainfall. In this environment, Semillon's early-ripening nature allows for a short harvest time, making it easier to avoid rain damage. A unique characteristic of this region is that when aged, it develops a distinctive style with notes of honey and toast.

Source: https://www.decanter.com/premium/experts-choice-hunter-valley-semillon-2-542091/

The secret to its flavor is a compound called **"sotolon."** This develops during the aging process, particularly in environments where oxidation occurs. Hunter Valley Semillon retains high acidity, making this chemical transformation easier.

Specifically, amino acids, sugars, and oxidized aldehydes in the wine react to create "sotolon," which produces unique aromas like honey, nuts, caramel, and even spices (such as curry powder). This aroma is known to be particularly prominent in long-aged white wines and botrytized wines.

・South Australia (Barossa Valley) 

Considered one of Australia’s oldest and finest wine regions, it is located 1,350 km west of Sydney.

The Barossa Valley has a hot and dry Mediterranean climate, but has succeeded in Semillon cultivation through the use of irrigation technology. Wines here are often rich and full-bodied. Because of the high heat, acidity tends to drop while sugar levels rise, making them well-suited for a full-bodied style.

・Western Australia (Margaret River) 

Located on the opposite side of the country from Sydney, Margaret River benefits from a Mediterranean climate and cooling sea breezes from the Indian Ocean. With significant day-night temperature differences, it is the ideal environment for grapes to retain acidity while accumulating sugar. It is often grown here to be blended with Sauvignon Blanc.

In cool climates, Sauvignon Blanc has high acidity and citrus notes, but in this region, it takes on a sweetness reminiscent of ripe passion fruit and pineapple.

Also, Semillon here does not have the sharp acidity of the Hunter Valley; rather, it is similar to the Barossa Valley in that it is a higher-sugar grape.

By blending Sauvignon Blanc (which is relatively light-bodied on its own and has lower aging potential) with Semillon (which provides a soft texture and aging potential), a well-balanced and appealing wine is created. (This blend has been common in the Bordeaux region of France for a long time.)

Hard to grow across Australia as a whole and culled by changes in market demand, Semillon nevertheless continues to shine in specific regions thanks to its unique charm. It’s deeply moving that 250 years after Captain Phillip’s decision, Semillon is still alive and well in Australia. I’m sure the Captain would be proud.

By the way, why did "Shiraz" rise to such prominence? Since we spent so much time on "Semillon" today, I’ll dive into the mystery of Shiraz next week.🍇 See you next week!!