The 5 keys to understanding wine terroir

What is a wine terroir?

The Harvard Business Review tells us there is one key question you’ll be asked first during a job interview.

That question is: “Tell me about yourself.”

You could come prepared with as many qualifications, awards and references as you like – it’s who you are that most captures your employers’ interest.

It’s the same with wine.

The word 'terroir' comes from the French, and while it sounds like plain old 'terrain' it's developed into meaning 'a sense of place'. 

So how can we understand a wine terroir? And how does that wine terroir affect the taste of wine grown there?

As the Washington Post points out, to a winemaker the ‘wine terroir’ is a precise science. 

Here we’ll cover the 5 keys to understanding wine terroir.


High temperatures can bring forward a harvest date, and winemakers will commonly use a refractometre device to test for optimum sugar levels before grape picking.



When talking about a wine terroir, temperature refers to average annual recordings rather than a single vintage.

Average temperatures tell a winemaker whether it’s even worth the cost of cultivating the soil and putting in expensive plantings. They tell a winemaker he or she might have to harvest quickly, or expect to let the grapes continue developing over a long, milder growing season.

Temperature also tells us wine drinkers what to expect from a wine.

Warmer temperatures during the summer encourage grapes to ripen more easily, and more rapidly. This converts much more of the grapes’ sharp and sour malic acid into sugars and darker colours. It means you can expect a bolder, fruiter wine in a terroir around Adelaide in South Australia (avg. 30°C in January) and higher acidity, lower sugar levels and a lighter body among wines in the Margaret River wine region (avg. 25°C in January). However what is ideal is when we are not rushed into picking because of heat, this allows the fruit to ripen as best as it can and flavours have time to develop.

According to the Grape Grower’s Handbook the optimum temperature for grapevine growth ranges from 25°C to 32°C (77°F to 90°F). Below this and grapevines struggle to grow – above this and grapevine photosynthesis slows due to increased respiration.


The Margaret River wine region is famous thanks to Indian Ocean breezes that help to keep the Australian heat down during the growing season.



Climate is key to explaining a wine terroir.

Beyond average temperatures, climate includes factors such as rainfall, humidity, wind, frost, hail and sunlight hours. Each of these factors contains a sweet spot for growing grapevines.

For example, according to the wine academy of Wine Investment grapes can’t produce sugar without adequate sunlight – but too much sun and they get sunburn. Rain is vital for wine growth, but too much and it can bring disease – especially during the harvest season. Strong winds can slow a grapevines’ growth, which isn’t a bad thing so long as adequate temperatures can ensure a long ripening season (such as in the coastal Margaret River).

Climate is broadly determined by geographical location, though certain regions can enjoy their own microclimate.

The Margaret River wine region is one the most famous in Australia because of its unique microclimate more akin to the Mediterranean than the scorched earth of inland Western Australia. Here’s how top wine expert James Halliday described Margaret River wine, according to its unique wine terroir:

“Margaret River has the most reliable climate of all the major wine regions – indeed all – of Australia. Its latitude and ever-present maritime influence of the Indian Ocean combine to give it high winter rainfall and a very even accumulation of heat throughout the growing season.”


This great blogpost from Vine Pair talks about the paradox of why bad soils are best for good grape growing. 



According to Wine Folly, there are four primary soil types for growing grapes:


  1. Sandy soils. These produce elegant wines with pale colours, low tannins, light acidity and high aromatics. 
  2. Clay soils. These stay cool even in the heat, and produce muscular wines with high extracts and strong colours.
  3. Silt soils. These retain water and heat, which can produce smooth and rounded wines with low acidity, but might need to be mixed with other soils to ensure adequate root growth and development.
  4. Loam soils. Loamy soils include equal amounts of silt, clay and sand as well organic matter. These soils are very fertile and often too much so for grapevines, producing grapes with little flavour and colour. 

The Margaret River wine region is one of the world’s most geographically isolated wine regions, with ancient soils (up to 600 million years old) and with 80% of plant species found nowhere else in the world.

The Margaret River wine terroir as with our vineyard is a mixture of soil types.  It is loamy – but it's very lucky to still be well-drained, low in nutrients, and hence not so fertile as you might imagine. This is what makes the Margaret River wine region so extra special among Australian wine terroirs – and why it can make for a stunning wine.

It's a paradox that bad soils typically make for good wines.

But as this great post from Vine Pair explains, winemakers want quality over quantity. Have you ever noticed how humungous, greenhouse-grown tomatoes taste a lot more bland than the toms your Grandma under-watered down the end of the garden during hot summers?

The best way to get great-tasting wine is to make the grapevine work hard in tough, low-nutrient soil. Otherwise, we're just drinking flavoured water. 


We are blessed at the UMAMU Estate to have a large reservoir on site, which helps to regulate the hot Australian sun even more than normal for Margaret River.


Topography is another key to wine terroir.

A vineyard on steep slopes can drain better, and receive more sunlight. High altitudes can also mean colder nights, which help to lengthen the ripening season and produce elegant, aromatic wines that age well (remember: tough growing conditions = good wine).

It’s also important to recognise the presence of bodies of water, which can keep a wine terroir cooler in summer and warmer in winter. The Margaret River’s location on a promontory surrounded on three sides by the Indian and Southern Oceans is key in keeping down summer temperatures, thanks to sea breezes. 

At the UMAMU Estate, we're blessed with a dam which helps to temper even further the Australian sun.

Mountain ranges can offer protection against elements like wind, rain and cold weather fronts. 

All of these factors in a wine terroir mean you can't just expect Californian wines to be grown in a hot climate – some wines are grown in the Napa Valley up to 2,600 feet (790m), on steep valley sides, and close to Pacific ocean breezes.


Our award-winning Margaret River wines are a combination of a fantastic wine terroir and a passion for making exceptional wine.


Wine terroir viticulture vs a winemaker’s knowhow

Don't be fooled into thinking a wine terroir by itself makes a wine.

There’s a common phrase among winemakers: “You can make bad wine from good grapes, but you can’t make good wine from bad grapes.”

The skill of a winemaker is a near-instinctive knowledge of their wine terroir and how to draw the best from a growing season – no matter what nature throws at you.

At the UMAMU Estate we believe that 80% of a wine is made in the vineyard through careful attention. And we always remind ourselves that it's easy to make a good wine (in a kind-mother nature vintage!) but it's something else to make an exceptional wine.

For wine drinkers, it's important to know a wine terroir and what one should expect from it – you'll then know what kind of wines you prefer from what kinds of terroir.