New World Winemaker Blog

“There is a place I love in Africa, that they call the rainbow land…Chris de Burgh”

I could not help over the past few weeks to realize the challenges that entities may face as a result of diversity…diversity in just about everything, all starting with changes in  DNA. I started thinking about similarities between South African ethnic groups and what lives on grapes (forgive me, but I am pretty parochial as wine is not only my job, but also my hobby…)

South Africa as a multi-ethnic nation has diverse cultures, languages and religions. Eleven official languages are recognized in the constitution. English and Afrikaans are of European origin. Afrikaans originated mainly from Dutch ancestry and is spoken by the majority of white and Coloured South Africans. Though English is commonly used in public and commercial life, it apparently is only the fifth most-spoken home language. All ethnic and language groups have political representation in the constitutional democracy. About 80% of the South African population is of black African ancestry, divided among a variety of ethnic groups speaking different native languages, nine of which have official status. South Africa also contains the largest communities of European, Asian, and racially mixed ancestry in Africa…I bet you did not know this about our Rainbow nation.

Now I will not elaborate any further on political issues or leadership challenges, as this blog is mostly about the diversity that occurs on the republic of grapes. As winemakers, we are required not only to have a winemaking persona, but also to have personas that reflect our knowledge of chemistry, engineering, consumer behaviour, finance and many others. We are also required to know something about microbes, as they not only occur naturally on and in grapes and wine, but also direct our product in what may be acceptable for the consumer, or not. They may be friends or foes, and their diversity makes it challenging to manage, particularly if you do not know the basic elements that govern their existence…am I starting to sound like a politician?

Anyway, managing complexities efficiently probably start with understanding the magnitude of the challenge. I was utterly amazed when I took the book “Biology of Microorganisms on Grapes, in Must and in Wine”, and started counting what actually occurs on grapes and in wines. Now I am not a microbiologist, and I do not wish to quarrel about physiological differences between Leuconostoc oenos and Oenococcus oenos, but I do think even if some of these are anamorphs of each other, or genetically closely related and the differences insignificant, the diversity is quite darn amazing! The following is a table of “bugs” that occurs naturally on grapes and in fermenting wines and musts (and I did not count the sub-species…:

Isn’t this amazing? Not counting strains and sub-species, Lactobacillus has more than 22 genera and species, acetic acid bacteria more than 18, and yeasts more than 26!

And the most important thing to remember, I suppose, is to either educate yourself as a manager that guides this immense diversity (“winemaker”) in the oenological principles, or surround yourself with people who can.

Wish some leaders could learn from this…

Bertus Fourie is a winemaker, turned Enology lecturer and creator of the Barista coffee Pinotage.

This blog can be regarded as the sequel for “Snow blower on Enceladus”, which I have posted in November last year. The blog was all about technology that uses CO₂ ice pellets to clean and rejuvenate the inside of barrels by “blowing” these ice pellets under immense pressure against the inside staves of barrels, leaving them clean and “disinfected”. Another advantage of course remains the fact that the condition of a used barrel can be inspected. Many winemakers was struck with complete and utter dismay at the sight of many a blister in the inside of these very pricy barrels…and most probably found the puss that “oozed” from these blisters a terrible reality.

Yet the challenge remains to manage barrels in such a way that you get what you want from them: Extraction of flavor, and introduction of oxygen. Yet both decrease as a result of extraction and blocked pores, as the barrels grow older. The other challenge is of course to maintain a good sanitary status after these barrels are emptied and filled with new wines, as spoilage organisms such as Brett and acetic acid bacteria literally get a “breather” in between emptying and filling…

Several techniques are at the disposal of winemakers to clean barrels. Many high tech barrel cleaning systems are currently on the market, from “ordinary” pressure cleaners, to units that can empty the barrel and clean it afterwards without having to move the barrels from the stack. It is possible to use dry steam or wet steam. You may even use chemicals such as SO₂ treatments or the patented “Thales cleaning” method. Yet again – different strokes for different blokes.

The purpose of this blog however, is to take a view on the “Barena” method. One of the differences to the Ice Jet System is that they do not physically dismantle the barrel. A rod is simply placed through the barrel’s bung hole, and quartz crystals are sprayed under pressure against the inside of the barrel. These crystals were sterilized by heating it up to 300 degrees Celsius several times. Approximately 30 kilograms of these crystals are used per barrel. The quartz removes less than a millimeter of the surface of the staves, almost like peeling off a skin from a litchi. The barrel is then rinsed with de-chlorinated cold water. Step 3 in the process is the “disinfection stage” where the barrel is steamed for 12 minutes.

The barrel is now ready to dry naturally. A disinfected silicone bung is put into the bunghole, and a needle through which SO₂ gas is injected, penetrated through the bung. This leaves the barrels treated and ready to be filled yet again.

Unfortunately the downside remains the transport of the barrels to the depot where they are treated and back to the cellars. I also like the fact that I can physically inspect the inside of the used barrels when I used the Ice blast technology, although you may argue that it is possible to look into a barrel with optical fibers…honestly, how many of us actually use these gadgets on barrel inspection day?

Nevertheless, I also like the idea of “blasting” (and opening blisters I suppose) away deposit and residue by force, “steaming” the pores open and bugs away, and finally treat it with sulphur. It all makes sense…almost like giving your barrel a facial.

The technology will soon be available in South Africa, and I really think it’s time to look at some hardcore evidence – which method will ultimately prevail? Let the wine decide…(or the bottom line?)…

Bertus Fourie is a winemaker, turned Enology lecturer and creator of the Barista coffee Pinotage.

It all started in the mid eighteen hundreds, when a gentleman with the name of Antonin Prandtl, invented the first dairy centrifuge in order to separate cream from milk. At that stage he was working (probably with some sort of butter addiction) for himself and not for Cadbury’s…

The principle was “refined” by Gustaf de Laval in 1879 who demonstrated the first continuous centrifugal separator, making its commercial application feasible. But what exactly is a centrifuge, and how can it add value to the wine industry?

A centrifuge is a piece of equipment which is driven by an electric motor that puts an object or liquid in rotation around a fixed axis, applying a force perpendicular to the axis. The centrifuge works using the sedimentation principle, where the centripetal acceleration causes denser substances (like yeast cells, grape particles, fining agents, etc.) to separate out along the radial direction. By the same token lighter objects (juice or wine in this case) will tend to move to the top. The net result thus, a very efficient separation of solids and wine.

Centrifugation technology has become so advanced over the years that it is considered a superior method for winery solids management and eliminates the need for unnecessary handling of wines and juices (with all its detrimental effects and risks like exposure to oxygen and consequent product losses & quality), e.g. several racking’s and pre-historic filtration actions.

I believe it is important to give compliments where it is due. A very fine piece of technology is the STS family of centrifuges. This is a superior method for optimal wine recovery from grape solids, fermentation lees and fining lees with negligible dissolved oxygen pick-up during the separation process, which was considered the major downside ages ago.

 So what exactly happens? Quite simple: Dirty liquid goes in, it is separated, and crystal clear liquid comes out…and of course solid matter or sludge that has the density of peanut butter at a moisture level of 95%.

In a few conversations with winemakers who use this technology, the following advantages came up: 1) Reduced juice and wine losses, associated with racking, filter aid adsorption, or even or de-sludge actions of older or under-performing centrifuges. 2) Reduced juice and wine quality “downgrades” .This classically happens where existing lees handling processes lead to the loss of quality as a result of oxygen pick up, or contamination, or human error. This of course may lead to a loss of freshness, loss of varietal integrity and character, or even reductive taints from prolonged exposure to lees. 3) Eliminating DE (diatomaceous earth) filtration, principally the lees Filter and Rotary Drum Vacuum filter not only reduce the amount of juice and wine handlings, but is also associated with direct hard savings in reduced DE consumption which also have health and auditing benefits. Occupational Health, Safety and Environment considerations of DE and the ability to proactively demonstrate a major reduction in DE usage in the cellar is an intangible benefit. 4) A key advantage over the older centrifuges is the very low oxygen pick-up, which is as low as 0.02 mg of oxygen per litre of wine. This means the same wine can be centrifuged multiple times during its maturation cycle, without the detrimental effect oxygen may have on particularly white wines. 5) If all the technical benefits are weighed, then it is also a no-brainer to see that the application of this technology also builds a very strong business case, and the immediate effect on the bottom line.

Key applications include clarification of: White juice from recently pressed grapes – cold-settled juice lees – white wines after primary fermentations (including yeast lees) – white wines after bentonite finings (including bentonite lees) – bentonite lees – stuck or sluggish ferments – late harvest and botrytis wines where primary fermentation must be stopped – Red wine after primary ferment (including gross lees) – gross red lees – red wine after malolactic fermentation – wines after cold stabilization – cleaning of wine with in-line cross-flow).

Forgive me if I start to sound like a STS representative… but I am just wondering if all directors or all big cellars know how much money can be saved on the bottom-line if the “optimal” technology or equipment is being used “optimally”…

Bertus Fourie is a winemaker, turned Enology lecturer and creator of the Barista coffee Pinotage.

Chinese checkers is a board game that can be played by two, three, four, or six people, playing individually or with partners. The objective is to be first to race one’s pieces across the hexagram-shaped gameboard into the “home” section, which is the corner of the star opposite one’s starting corner, using single-step moves or moves which jump over other pieces. Others keep playing to establish 2nd, 3rd, 4th, 5th, and last place finishers.

Now what on earth does a board game have to do with wine, or anything remotely associated with wine, except for the fact that in some cases the two might go hand in hand… wine and games that is… Well, nothing really, except for the fact that predicting the style and quality of a wine as a result of the fruit and oenological processes, remains one of the most important and difficult parts of a viticulturist and winemaker’s job and is sometimes more luck than wisdom (This was confirmed by a very interesting sensorial lecture by Professor Heyman of UC Davis a few days ago).

Imagine having a tool in the laboratory which helps you to assess the maturity kinetics of your vineyards and its fruit profile helps you to optimize the picking date according to the desired wine profile and finally, helps you to create more consistent wine profile results, year after year, with multiple vineyards or blocks of the same cultivar.

The technology, called the Dyostem system (Berry Maturity Analyses system), to measure berry skin colour has been developed by Vivelys Society (France) and Montpellier SupAgro (France) a while ago and is currently being assessed commercially in the Northern and Southern Hemisphere. According to Professor Alain Deloire of the University of Stellenbosch, the method uses the evolution of the berry colour by applying optical techniques, as an indicator of berry ripening, which of course relate to the wine’s aromatic profile. In short: The average colour of the berries “predicts” the wine style as a result of the ripeness level of the fruit.

The term “optimal ripeness” is such an important, yet complex term that not even scientists can agree fully on a definition or all the complexities that it entails. Yet, the significance of “optimal ripeness” is reflected not only in the development of technologies like the Dyostem system and formal sensory techniques (BSA or Grape Berry Assessment), but also in the jargon used by winemakers when presenting wine tastings or trying to flog a few bottles to a restaurant.

Winemakers agree to the fact that “optimal ripeness” bares direct relation to the style of the required wine, which in turn is dictated by market or by the objective to produce a wine that reflect the expression of a typical terroir related profile.  The classical indicators of “ripeness level” include sugar level or potential alcohol, natural acids (particularly malic and tartaric) and pH and of course various and diverse methods of spectral analyses to give us some insight into the colour ripeness and tannin or “mouth feel” ripeness. All these parameters strongly relate to the perception of the taste of the wine.

In lectures to students, when asked the question “but when exactly do you decide when to harvest?” of course I cannot give them a straight and simple answer. I do however think back to Christopher Walken’s answer to his daughter’s question “what should I do Dad?” in the movie the “Wedding Crashers”: “The best you can do is to use all information at hand to make the best possible decision.”

Dyostem I have never had the privilege to work with, but when it reaches the point where it does exactly what it was designed for, I am getting myself one of those…or like Orange winemaker Justin Jarrett said “I can walk down the rows of my vineyard and taste fruit and get it right, or hope I get it right… but I guess if I get it wrong, I’ll get it really wrong. This way you have some science to the process of determining picking times based on the flavours you want…”

Bertus Fourie is a winemaker, turned Enology lecturer and creator of the Barista coffee Pinotage.