New World Winemaker Blog

This is a favourite claim of the so-called “natural” or “non-interventionist” winemaking movement. One of the reasons why they claim it is better to do natural fermentation instead of using commercial yeasts is that commercial yeasts with their “predictable aromatic profiles” can make, say Sauvignon blancs from Europe, taste like New Zealand Sauvignon blancs. Or worse even, it can make Chenin blanc and Ugni blanc taste like Sauvignon blanc. I have personally been in a tasting with a group of oenologists representing most of the wine countries in the world where the Germans presented a Muller-Thurgau. Everyone, including the French (much to their despair) thought it was a Sauvignon blanc. I have also once given a South African Colombard to a group of French winemakers to taste and they also believed it to be a Sauvignon blanc.

So how does this happen and is it “wrong?” The “naturalists” feel it is wrong. Winery sales figures show it is “right.” Consumers like these aromas. Wines around the world can taste similar because we make wine mostly from one specie – Vitis vinifera. Then we also use yeast which originates from mainly one specie – Saccharomyces cerevisiae. Each grape variety is not equipped with a unique set of flavour active compounds. Only the combination is unique. This combination will differ between grape varieties as well as within the same grape variety in different vineyard blocks and vintages. The main aromatic compounds found in grapes are monoterpenes, C13 – norisoprenoid derivatives, pyrazines, thiols and certain amino acids that can be converted to aromatic higher alcohols and esters. The latter two groups are non-aromatic in grapes and converted by the fermenting yeast to a flavour active form. In some cases pyrazines found in Sauvignon blanc are seen as a positive. When present in reds such as Cabernet and Merlot it is seen as a negative.

Thiols smell like guava, passion fruit, grapefruit, black currant and gooseberry. Sauvignon blanc happens to have the highest thiol precursor concentration in the grapes. Wine yeasts convert these precursors to their flavour active forms and differ in their efficacy to do so. Many other white grape varieties contain these thiols but in lower concentrations. So unless you use yeasts that are very good in expressing these aromas and combine it with certain winemaking practices, these aromas will go unnoticed – as they did for many years. However, winemakers around the world are upping their game – competition is tough. They are using modern technologies and as a result they are tapping into these flavour profiles of their grapes that they did not know exist. As a result they can sell their wine in a bottle and not a box. Is this wrong?

Yes yes stone me, I work for a wine ingredients company and I have a commercial interested in winemakers using yeast. However, my clients who’s Chenins, Colombards, Ugni blancs, Muller-Thurgaus and Verdelhos that have “Sauvignon-like” aromas are certainly not complaining about their sales. If you have very good quality grapes then you have many other flavour active compounds that can “sell” your wine for you and you don’t necessarily have to make such an effort to express the thiols. When you have less than top quality grapes, then optimising what you have is a good idea and if that means optimising thiol expression then so be it.

Just for the record – contrary to popular belief I do support natural / un-inoculated fermentations when conditions are right for it. See my earlier blogpost: Natural vs. inoculated fermentations.

Most people have heard about the French paradox so I thought I’d inform you about the lesser known German paradox.  I started travelling to Germany in 2001 as a fermentation consultant to the wine industry and did so on a yearly basis until starting a family put me out of international travel for a while. I tended to visit the same people every time I went and it was fascinating to monitor their progress year after year as they started implementing what I advised. I must admit I was sometimes quite surprised / relieved at the positive effects of my advice myself.  Wines that I thought were beyond hope (some Muller-Thurgaus) were all of a sudden mistaken for a new world Sauvignon blanc! Now whether that is a good thing or not is a topic for another day. The mere fact that it went from unpalatable (in my opinion) to very pleasant indeed is what one should focus on.

In 2001 most of the cellars I visited (take note I am not generalising) fermented their whites at temperatures between 18 – 22°C. This is fine for what I call “forgiving” grapes such as Riesling. Riesling has a lot of varietal character not influenced by yeast and fermentation temperature and therefore top quality white wines can be produced at these fermentation temperatures. However, there were certain other candidates that I won’t mention by name out of fear for my safety and that of my family’s, that quite honestly were not so great. I focussed my advice on these wines, what the winemakers themselves viewed as “neutral” varieties. They were all German varieties that I had no experience in tasting so I had no idea if they were truly “neutral” or not. I decided to investigate by advising colder fermentation and more aromatic yeast strains. These winemakers gradually shifted their fermentation temperatures to between 15 – 17°C and changed to different, more aromatic, yeast strains. Some now even ferment at 13 – 15°C.

And this is exactly where the paradox set in… The wines were much more aromatic. All of a sudden the grape varieties were not so neutral after all. The winemakers loved it, the consumers loved it, their buyers loved it, I liked it, BUT they could not sell it. Why not? Because they could not pass the certification of the wines. They were refused their QBA numbers because the wines “were not typically German.” Some kept on submitting the wines for certification until they struck a “younger” panel that would then pass the wines – only just though. The irony of the situation was that these “new style” German wines would then sell out in three months!

The situation has subsequently become better and I believe it becomes easier every year for winemakers to pass their more modern style (but still identifiable as German) wines, especially in the southern wine producing areas. But it certainly is a very strange and frustrating position to be in – to struggle to get certification for your better quality wine. A paradox indeed.