What causes pepper aromas in wine?

Quick answer

Pepper aromas in wine are usually linked to volatile compounds that smell peppery, most notably rotundone. Rotundone is a potent, grape-derived aroma compound associated with black-pepper character in some wines, particularly some Shiraz/Syrah.

The amount of rotundone can vary with grape variety, vineyard site, climate, vintage and fruit lot. Winemaking choices—including skin contact and possible stem contact—may influence how much of the compound is extracted and expressed.

But pepper is a sensory descriptor, not a single diagnosis. When someone says a wine smells of pepper, they may mean black peppercorn, white pepper, dried spice, herbal spice or a broader savoury impression. Not every peppery wine contains the same balance of compounds, and not every person will smell it in the same way.

Rotundone: the leading explanation

Rotundone is a highly potent aroma compound in the chemical family known as sesquiterpenes. Research led by The Australian Wine Research Institute identified it as an important contributor to black-pepper aroma in some grapes and wines.

It is particularly associated with some Shiraz/Syrah wines, although it has also been reported in other varieties. That association is useful when tasting, but it is not a rule: a Shiraz can be rich and fruity without obvious pepper, while wines from other varieties can show spicy or pepper-like notes.

Rotundone occurs mainly in grape skins, and it can also be present in stems and leaves. For the finished wine, what matters is not simply whether a grape contains the compound, but how much is present and how the wine’s production and overall composition affect its expression.

Why one wine is pepperier than another

Grape variety

Some varieties are more likely than others to contain rotundone or to show a pepper-associated character. Shiraz—called Syrah in many other parts of the world—is the best-known example in Australian wine conversations.

Variety does not work alone, though. Two wines made from the same variety can smell quite different because their grapes came from different sites, seasons or fruit lots.

Site, climate and vintage

Research links rotundone variation with growing conditions, site and temperature-related factors. Studies have also found that rotundone can vary within a single vineyard.

This helps explain why pepper character is often discussed as a site or vintage effect. Some cooler-climate Australian Shiraz can show distinctive pepper, but “cool climate” is not a guarantee and no Australian regional label promises a pepper aroma.

A region can create conditions that make a style more likely; it cannot determine exactly what every bottle will smell like.

Stems and whole-bunch fermentation

Because rotundone can occur in stems, stem contact is relevant to the discussion. Whole-bunch or whole-cluster fermentation may change the extraction and balance of spicy, herbal, stemmy and pepper-like aromas.

However, whole-bunch fermentation does not automatically create pepper character. Stem maturity, fruit condition, maceration, fermentation and the wine’s other aromas all contribute. It is better to treat stem inclusion as one possible influence rather than a simple recipe for pepper.

Fermentation and maturation

Skin contact and extraction can affect how grape-derived compounds move into wine. Fermentation and maceration therefore have the potential to influence pepper expression.

Maturation can change the balance of aromas, but there is no sound basis for saying that oak or bottle age is the universal source of classic black-pepper aroma. Oak may contribute overlapping impressions such as clove, toast, cedar or baking spice, which can sit alongside pepper without being the same thing.

Why pepper does not always mean the same thing

“Pepper” covers several related but distinct tasting impressions. A taster might notice:

• Black pepper or peppercorn: the classic sharp, dry-spice impression often associated with rotundone.
• White pepper: a lighter or more lifted pepper-like note.
• Spicy: a broader category that may include pepper, clove, anise or baking spice.
• Herbal or stemmy: green, leafy or savoury notes that may accompany spicy character.

These descriptors are helpful ways to communicate perception, but they are not interchangeable chemical diagnoses. A wine that smells “spicy” does not necessarily smell of black pepper, and a pepper descriptor does not mean piperine—the compound responsible for pepper’s heat—is present in the wine.

Why people disagree about pepper aroma

People vary considerably in their sensitivity to rotundone. Some tasters can detect it at extremely low concentrations, while a sizeable minority may not detect it even when it is present at much higher levels. This is sometimes called specific anosmia: unusually low sensitivity to one particular odorant.

The wine itself also matters. Fruit, oak, tannin, alcohol, acidity and other aroma compounds can mask, support or change the overall impression. Threshold measurements also vary depending on whether the compound is tested in water, wine or another sample, and on how the sensory test is designed.

So if you smell black pepper and another person smells only fruit or herbs, neither of you is necessarily tasting incorrectly.

Is pepper a wine fault?

Not by itself. A pepper aroma can be a natural part of a wine’s sensory profile and does not indicate poor quality.

Smoke taint, reduction, volatile acidity and spoilage can create strong or unusual aromas that a drinker may describe imprecisely. But these are not automatically the cause of a genuine pepper character. Assess the whole wine rather than diagnosing a fault from one word.

Pepper is also not proof of a particular production method, grape variety, region or age. It is an observation about how the wine smells to you.

How to taste pepper more carefully

Try this simple exercise:

1. Smell the wine before swirling it.
2. Swirl gently, then smell again.
3. Ask whether the impression is black peppercorn, white pepper, dried spice, herbal or stemmy.
4. If available, smell actual peppercorns or dried herbs as reference points.
5. Write “I smell black pepper” rather than “this wine was made with whole bunches”.
6. Compare notes with another taster, remembering that sensitivity differs.

This approach keeps tasting evidence separate from assumptions about how the wine was made.

Frequently asked questions

Is pepper aroma always caused by rotundone?

No. Rotundone is the best-established contributor to a classic black-pepper aroma in some wines, but “pepper” is a broad sensory description and other compounds or overlapping aromas may contribute.

Is all Shiraz peppery?

No. Some Australian Shiraz shows pepper character, but Australian Shiraz varies widely. Variety, site, vintage, ripeness, winemaking and individual sensitivity all matter.

Does whole-bunch fermentation make wine taste of pepper?

Not automatically. Stems may influence extraction and the balance of spicy or herbal aromas, but whole-bunch fermentation is not a guaranteed cause of pepper character.

Does oak create pepper aroma?

Oak can add spicy impressions such as clove, toast or cedar, but the strongest evidence for classic black-pepper character points to grape-derived rotundone rather than oak as a universal cause.

Why can I smell pepper when my friend cannot?

People differ in their sensitivity to rotundone and in the words they use for aroma. Your friend may genuinely be less sensitive to the compound, or may perceive the same aroma as spice, herbs or savouriness.