New World Winemaker Blog

“I have walked across the surface of the Sun. I have witnessed events so tiny and so fast they can hardly be said to have occurred at all. But you, Adrian, you’re just a man. The world’s smartest man poses no more threat to me than does its smartest termite.” – Doctor Manhattan

The above quote by Doctor Manhattan from the 2009 movie, Watchmen, made a very big impact on me. Not only did Doctor Manhattan have extraordinary physical capabilities, but also boundless intelligence and wit. Most scintillating however, was his ability to observe and control miniscule atomic particles and impossibly fast to imagine metaphysical events. Doctor Manhattan didn’t really strike me as a lush, but I’m sure that he would have been fascinated with the chemically complex and ever changing matrix that is maturing wine.

As a former minor winemaker at quite a few cellars, my favorite place has always been the barrel maturation cellar. Barrel ageing is ostensibly one of a wine’s more important stages of evolution before bottling. But how exactly does wine change during barrel ageing and what effect does it have on the countless chemical reactions taking place in wine every second? The main effect of oak barrel ageing is twofold. Wood character is introduced (the rate and intensity is mostly dependent on fill status of the barrel) and oxygen is very slowly introduced to the wine. Generally speaking, this results in softening of the harsh tannins and flavors present at the end of fermentation. Oak is a fascinating substance, which has a profound and remarkable effect on the flavor chemistry of wine. Key oak derived compounds are tannin, lignin, cellulose and hemicellulose.

Tannin plays a vital role in barrel ageing. Although most tannin in wine comes from the grapes, some of it is also liberated by the barrel during ageing. So what exactly is the deal with tannin? An experienced winemaker will instinctively know how to optimally merge and balance the tannins extracted during the youthful stages (fermentation, skin contact and pressing) and the mature stages (barrel ageing and blending). For instance, more tannic grape varieties such as Tannat, Cabernet Sauvignon, Nebbiolo and Shiraz cannot be approached the same as the less tannic Pinot noir. Once again, winemaker experience is paramount.

OK, now hold on to your chemistry hat, here comes the hard (but interesting) bit! Phenolic compounds (consisting of natural phenols and polyphenols) in wine are largely responsible for imparting taste, colour and mouthfeel to wine. They include phenolic acid, stilbenes, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). Natural phenols can be separated into flavonoids and non-flavonoids. The latter group includes stilbenoids such as resveratrol and phenolic acids such as benzoiz, caffeic and cinnamic acids. The former group includes anthocyanins and wait for it… tannins!

What would a good red wine be without vanilla flavors, sweet and toasty aromas and notes of tea and tobacco? Specific compounds create these nuances in finished wine, for example: volatile phenols containing vanillin; carbohydrate degradation products containing furfural, a component yielding a sweet and toasty aroma; “oak” lactones imparting a woody aroma; terpenes providing “tea” and “tobacco” notes, and hydrolysable tannins, which are important to the relative astringency of the wine. Take note, every time you’re quaffing a wine (hopefully a worthy vintage), you’re consuming everything you’ve just read above. If this doesn’t sit quite right with you, then I guess nothing much will.

They say you should have respect for your elders. So, tread lightly the next time you pass through a barrel maturation cellar. You might even see Doctor Manhattan skulking around in the dark, silent corners…

Bernard Mocke is a technical consultant for Oenobrands.

If you gaze upon these images for a few moments (some might need more time), you will notice a few things. Most significant is that things tend to not only get more colorful towards the end, but also more revealing. Those of you who aren’t too thrilled by the images above might wonder what scantily clad damsels have to do with the evolution of wine technology. Best you read on then.

During an ancient and alcohol fueled conversation, a chef expressed his discontent at the notion of wine research. His bottom line was that you cannot drink research. After a few moments of thought (which was remarkably difficult at that time), I pointed out the obvious improvement of wine during the past 100 years. Also the availability of science and technology allowing for the abundance of excellent wines which are currently available. Just like the evolution of the bikini, science allows you to make things more revealing. To strip things down to the basics and to fulfill a very important need…

Alcoholic fermentation by yeast is a natural and beautiful thing. One might even call it a simple process. Nonetheless, this seemingly simple process is governed by hundreds of thousands of elements, chemicals, enzymes and micro-organisms. Louis Pasteur, often called the father of microbiology, paved the way for the identification, enumeration and understanding of all micro-organisms. His humble beginnings in the early 1860’s allowed him to conclude that micro-organism can lead to wine, beer and milk spoilage. Back then, all germs were seen as the enemy. Who would have thought that more than 150 years later, we add specific yeast and bacterial cultures to wine in order to make better wines.  You can practically get a wine yeast for any grape variety, winemaking condition and style that you desire. In 1953, James D. Watson and Francis Crick suggested the first correct double-helix model of DNA structure, which with ongoing research and refinement allowed us to study yeast genes and this helped us with the continuing selection and improvement of yeast strains for specific new world winemaking conditions.

Enzymes have also come a long way since their discovery in 1833 by Payen and Persoz, who treated an aqueous extract of malt with ethanol and precipitated a heat-labile substance which promoted the hydrolysis of starch. Nowadays, it is hard to imagine any commercial winery without the use of all the different enzymes. Not only do enzymes improve wine quality, but they also make life easier for the winemaker. For example, a settling AND skin contact enzyme like Rapidase Expression (Oenobrands) allows for a single addition at crushing of white grapes. Not only is varietal character enhanced, but more than ample enzyme activity remains after pressing in the settling tank.

Remarkable advances have also been made in cellar and wine treatment machinery. This is not surprising, seeing that our club wielding, cave-dwelling  ancestors already tried their hand (or should I rather say claw) at winemaking back in the spry 4000 BC’s. The oldest known winery is located in the “Areni-1″ cave in the Vayots Dzor Province of Armenia.  This winery, which is over six thousand years old, contains a wine press, fermentation vats, jars, and cups. Archaeologists also found grape seeds and vines of the species Vitis vinifera. Gravity was all the rage before pumps were designed, but there is a refreshing new push towards using gravity again in modern cellars.

Wine treatment was also not left behind. Where in the past, winemakers had to deal inventively with maladies such as high alcohol, volatile acidity, Brettanomyces-taint etc., the advent of reverse osmosis and spinning cones offers cost effective solutions.

Sir Francis Bacon said in 1597: “Knowledge is power.” Science allows humans to empower themselves. And to feel smarter. If you don’t believe this, just think of how smart you usually are after a few glasses of wine…

Bernard Mocke is a technical consultant for Oenobrands.

During my recent harvest stint in Germany, my host, Christoph Hammel uttered many memorable (and some that I am not allowed to mention here) pearls of wisdom. He told me about a meeting where some of the biggest names in German winemaking and professors associated with the wine industry were present. A very well know professor publically stated that his belief system does not have any room for the theory that yeasts impart any aroma to a wine fermentation. At this, Christoph got up and glibly replied: “My dear sir, it is not a question of belief. It is a question of knowledge.” The subsequent pandemonium that ensued was apparently quite noteworthy (hence the photo above).

Christoph is a big believer in using technology, specifically technology that can be used to make wine, and wine processing, better. Even more specifically, he is a big believer in additions.  He always said to me that he makes wine that people want to drink and if this can be achieved with the addition of enzymes and other winemaking tools, so be it. Every addition that he does is done for a reason. One thing can be said with certainty and that is that Christoph believes in the “interventionist” approach to winemaking. A lot of winemakers like to claim that their wine is made “naturally” and with the least possible human intervention, but Christoph is at the complete opposite of the spectrum. He has some pretty far out and amazing ideas and some might even call him a renegade or a cowboy after hearing about his yeast mixing and addition regimes!

As far as the additions are concerned, Optiwhite (Lallemand) is one of his stalwarts. This is usually added at the beginning of fermentation. β-glucanase and β-glycosidase enzymes  are added at the end of fermentation (at about 0°Brix). Depending on the structure and quality of a specific wine, ascorbic acid is also added right at the end of fermentation. DAP is added at three stages and is sometimes even added in divided dosages during the day, depending on the fermentation bouquet. In addition to DAP addition, thiamine is added to all musts. This is done simultaneously with sugar addition. It is well known that fungal infection on grapes depletes thiamine and it is therefore an excellent prophylactic measurement against stuck, sluggish or smelly ferments. For each addition, a cost to benefit decision is made. For instance, light and easy drinking wines will not get all the bells and whistles. The more expensive wines will get a full range of stuff added.

If Christoph was not such an excellent winemaker, I would have said that he missed his true calling in life: A chef! A chef who is forever mixing, adding and tasting, mixing, adding and tasting…

“Don’t make a big monkey dance about choosing a yeast, just decide if you want esters or thiols!” This is one of the more memorable sentences that was uttered by Christoph Hammel during my recent harvest stint at his cellar in Germany. Before I put this sentence into context, I should mention that the Hammel Weingut has been in business since 1723. This proud winemaking tradition is continued by veteran and outspoken winemaker, Christoph Hammel. His skills include a combination of modern thinking, creative planning and solid experience based on many years of making wine with a scientific yet artistic touch.

Christoph is such a staunch believer in Anchor Wine Yeast, I guess that you could even call him an Anchorfile. He has repeatedly achieved success on a variety of grape varieties such as Grüner veltliner (fermented with Anchor Exotics and Anchor Alchemy I), Scheurebe (Anchor Alchemy II), Sauvignon blanc (Anchor Alchemy II), Dornfelder + Portugieser Rosé (Anchor Alchemy I and II), Müller-Thurgau (Anchor Alchemy I), Chardonnay + Weissburgunder (Anchor Alchemy I) and Sylvaner (Anchor VIN 2000), Riesling (Anchor VIN 13 and Anchor Exotics). Of special interest will be some the combinations of yeasts that Christoph likes to co-inoculate, such as VIN 13/NT 116 (also Anchor) and VIN 13/NT 116 together with Laffort X5. I have seen that these combinations have a massive effect on floral, fruity and tropical aromas, but no negative effect on fermentation kinetics.

Alex Halberstadt has the following to say about Sylvaner: “Nobody dreams about Sylvaner. Mentioning it in a group of wine people is akin to professing an interest in the finer points of cardboard fabrication. The grape bums people out.”

However, even a neutral grape variety such as Sylvaner stands to gain from these mixtures. For example, I inoculated Sylvaner with NT 116/VIN 7/X5 (as per Christoph’s instructions). Some of the tasting notes that I made over the course of the fermentation were: “tea leaf, fig, apple, floral, banana, grapefruit, spicy, curry, herbal, white pepper, grapefruit, and apricot”. In theory a more complex wine is possible because of the ester and thiol production of these yeasts and this is exactly what you’ll get in real life!

Something else that Christoph does, is oxygenation of the must and water mixture during yeast rehydration. In the photo below, you’ll see the white bin in which yeast is rehydrated and behind the bin you’ll see an oxygen tank.

Typically, the rehydration mixture is cooled down at 5ºC increments (with ample time intervals) until a temperature difference of approximately 5ºC is observed between the rehydration mixture and the must to be inoculated. Note that during all this, the rehydration mixture is continuously oxygenated by adding a steady trickle of oxygen. The rehydrated and happy yeast is then simply pumped to the tank in question. Christoph swears by this method and cannot remember the last time he suffered a stuck ferment. For more information on the science behind this, you are welcome to read my previous blog titled: “Is your yeast on sterols?”

More to follow…

Bernard Mocke is a technical consultant for Oenobrands.