What Is Wild Yeast Fermentation?

Harry Lambourne
7th June 2023

Wild Yeast Fermentation is becoming a hotly debated topic in the world of wine-making. However, this is far from new.

Humans have been making wine for many thousands of years. However, it wasn’t until Louis Pasteur came around in the 19th century that we truly began to understand cultured yeasts and what makes those grapes into wine.

Before this time, there was no debate to wild yeast fermentation. It was the only way in which wine was produced. It remained somewhat mysterious, as no-one could completely understand why these grapes were turning into such delicious juices.

Now, through the magic of science, we understand and this faces winemakers with a choice. Either they can use the wild yeast, (also referred to an ambient yeast), that appears naturally on the grapes to cause fermentation. Or, they can use cultured yeasts to bring the fermentation process about.

There is no making wine without fermentation
There is no making wine without fermentation

Over this article we’ll take you on a quick look into what these two forms of yeast are, the history behind their use and the pros and cons for each method of production. Don’t worry, we’ll also give you a few examples of wines which were made the ‘wild way’.

Wild Yeast and Cultured Yeast

There are, broadly speaking, two types of yeast. They are ambient yeast and cultured yeast. Ambient yeasts are derived directly from the skin of the grapes, (also referred to as the ‘bloom’). They are their naturally and always present, hence the term ‘ambient’ or ‘wild’ yeast. Wild yeast is purported to provide unique and complex flavours, as well as adding texture to the wines. However, they have the issue that winemakers cannot control which yeasts are present. They are more likely to provide faulty wines, or simply unbalanced wines.

On the other hand, we have cultured yeast which has the biological name of ‘saccharomyces cerevisiae‘. This is regularly used in products such as bread, cheese, yoghurt and beer. This strain of yeast is regularly selected and used by winemakers as it has the ability to consistently produce wines which possess desirable qualities. However, some claim that through using mass-produced yeast, the wines exhibit ‘mass-produced’ flavours. The taste of the wines reflect the yeast, rather than the terroir in which they are grown.

Interestingly enough, s.cerevisiae is present in vineyards naturally as well, in roughly 1 out of 1000 berries. Even with wild yeast fermentation it often plays a role in the later stages of production, as many wild yeasts are unable to perform consistently when wines reach above 6% ABV.

At its core, the debate is between stability and consistency, or the exciting and different, yet unreliable. Remember, there are two sides to every story though. So, we’ll take you through the history of these two yeasts and where they’ve had prominence before we review some of the pros and cons of using wild yeast fermentation that go beyond this simple dichotomy.

The History of Wild Yeast and Cultured Yeast Fermentation

We’ve mentioned that wild yeast fermentation is unquestionably the original way of producing wine. It was the only way to produce it, but cultured yeasts grew quickly in popularity after being widely adopted by New World winemakers in the 1960s.

New World winemakers were looking to make a name for themselves in a newer industry compared to those which had been commercially producing wines across Europe for hundreds of years.

They looked to produce clean, consistent and fruity wines which most consumers would find attractive. They didn’t have the same tie to terroir as Old World wine nations. The initial goal for many who adopted cultured yeasts was to produce a reliable product which had commercial appeal. This was undoubtedly a success and New World wines exploded.

After continued success, they then saw the chance to exploit this wild yeast debate again. They introduced wild yeast fermentation back into circulation, in small batches. Using this as a marketing tool, to promote something different from the normal. Indeed, this is how many wild yeast wines are marketed today.

Conversely, Old World Wines were earlier adopters of cultured yeasts, introducing them over the last century. This has meant that modern perceptions of their wine often go hand in hand with the cultured yeasts that they’ve been using.

It’s unsurprising that nations like France, would be earlier adopters as Louis Pasteur was making these discoveries on home soil! However, you can still find plenty of old world wineries which use wild yeast to this day.

White Wine Grapes Fermenting
White Wine Grapes Fermenting – Wild or Cultured?

Now, what are the benefits and drawbacks to wild yeast?

The Pros of Wild Yeast Fermentation

Taste and complexity will be argued as a major positive for wild yeast fermentation. Many argue that it adds texture, smoothness and complexity. A unique array of flavours are available through wild yeast simply because you can never be certain what you are going to get.

This unique array of ‘funky’ flavours is what has made wild yeast fermentation so desirable in the natural wine craze. If you’ve ever had a natural wine, of which there are tons of great examples, you’ll note that it often displays different tasting notes to, (for want of a better word), ‘standard’ wines.

The same grape variety and region will often show slightly more sour and funky aromas when it is a natural wine, not dissimilar to cider or kombucha. Some wine lovers find these deeply desirable, but some do not. This is certainly a matter of personal preference.

While ambient yeast can produce some unique and interesting flavours, you may not want unique and interesting if you’re spending a big chunk of change on a big and expensive Bordeaux. You may want the tastes that you associate with the grape, the region and the producer.

The Cons of Wild Yeast Fermentation

While the potential upsides are evident, there are certainly some pitfalls to wild yeast. It is far more unstable. This can mean that the flavours can’t be controlled, some people often describe natural wines as having a ‘barnyard’ quality. While an acquired taste for some, it is far from the expected norm with wine.

Beyond that, wild yeast can often fail to function when ABV rises. This can lead to very light, low ABV wines. Again, it can be seen as a desirable quality but isn’t the ‘standard’. Even if required ABVs are reached, then you there is a far greater risk of creating unbalanced or even faulty wines.

Perhaps the most interesting criticism comes from one of the most talked about positives of wild yeast fermentation. This is the unique and ‘more complex’ flavour profiles which are espoused as a greater reflection of terroir.

Some winemakers claim that in fact, this clouds the reflection of terroir. Each year you get a different final product, which reflects the ever-changing nature of wild yeast. This means that really the wine is showing you the characteristics of the yeast, not the terroir. This testimony coming from a Loire Valley winemaker here.

Leading from this point, to say that the use of cultured yeast is stopping the terroir from being reflected may be reductive. Winemakers use a variety of techniques. They can age the wines in oak, they can pick at night to retain freshness. We wouldn’t call this ‘betraying the terroir’.

Terroir is a huge part of what makes the wine we love great, but so do the actions of the winemakers. Wild yeast wine can be fantastic, but so can cultured yeast wine. It’s well worth trying something which can represent a real unique experience, but it’s not time to throw out cultured wine.

Regardless, we couldn’t leave you without recommending some wild yeast wines that are well worth a go!

Wild Yeast Wine Gift Box

Wild Yeast Wine Gift Box
Wild Yeast Wine Gift Box

This Gift Box includes three great organic wines which are all made using wild yeast. Red, white and rosé wine that give you a great chance to sample some wild yeast wines.

From the Rhône Valley, we’ve got the Clos Bellane Côtes du Rhône Villages Red. A wonderfully complex and fresh Côtes du Rhône. It’s grown at altitude to lock in light and delicate flavours. Then, it displays some intriguing and unique tasting notes including elderberry, green pepper and graphite. Maybe the wild yeast at work?

Next up is an organic Verdejo from Bodegas Menade. Crisp, clean and delivering a wonderful punch of tropical and citrus fruit flavours alongside interesting herbaceous notes such as laurel, thyme and fennel. Maybe that’s the wild yeast doing it’s thing yet again!

Finally, a fantastically unique rosé which utilises 60 year old bush vines and the indigenous Trepat grape variety. It’s Succés Vinicola’s Patxange Trepat Rosé. Concentrated flavours of tart red fruits and watermelon alongside red plums and subtle herbal and saline notes. You know what those funky notes are coming from by now.

If you’re interested in purchasing this gift box and trying some great wild yeast wines, then click here.

So, simply a marketing gimmick or a revolutionary way to reinvent wine to its original state? You decide! Get trying some wild wines and decide for yourself!

If you want to treat yourself, or someone else in your life, don’t forget to check out our Monthly Wine Subscription and Gift Wine Subscription products. Each month you’ll receive hand-picked wines from small, independent family winemakers who focus on organicbiodynamic and sustainable viticulture. Learn more here:

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