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New World Wine Maker Blog

Shiraz wines made from vines with different training systems

by Wessel du Toit, Petri de Beer & Albert Strever – Wineland

The main aim of this study was to investigate the colour and phenolic evolution of Shiraz wines obtained with different training and canopy treatments.

Phenolic compounds play an important role in the sensorial composition of red wines, such as Shiraz. However, how differences in the phenolic composition of Shiraz wines differ over time during ageing has not been well documented.


Experimental layout

An experimental Shiraz block (clone 9 on 101-14-Mgt rootstock) at Stellenbosch University’s Welgevallen farm was used for this research. Vines were spaced 2.7 x 1.5 m and grown on a seven-wire training system for the vertical shoot positioning system (VSP) treatment. Part of this vineyard was converted to a Smart-Dyson (SD) training system. Upper and lower shoots of the SD were also harvested separately. An additional treatment consisted of a reduced treatment (R), by removing the top shoot and it’s grapes on a two bud spur at flowering time.

Grapes were harvested at the following parameters during the 2012 and 2013 vintages: pH 3.5 to 3.8, TA 4 to 4.5 g/ℓ and Balling 23 to 25 °Balling. Wines were made on small scale at the experimental cellar of the Department of Viticulture and Oenology (DVO) at Stellenbosch University, using Saccharomyces cerevisiae D21 (Lallemand) and Oenococcus oeni (Alpha, Lallemand) as lactic acid bacteria. After fermentation the wines were bottled in 750 mℓ bottles and aged. Analyses were done on the wines after the completion of malolactic fermentation, after six months (both 2012 and 2013) and 12 months (2012) of bottle ageing.


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Meet Johnnie Calitz – Winemaker at Glen Carlou

Q. When and where were you born ?

“I was born in Calitzdorp in the Little Karoo on 14 September 1982.”

Q. Where did you study and what qualifications do you have ?

“I graduated from the University of Stellenbosch in 2004 with BSc Agric Viticulture and Oenology.  Since then I obtained the Certificate from CFPPA de Beaune for theory/practical on Burgundy wines in 2009.  And the Cape Wine Academy Diploma in 2012. I did postgraduate  Diploma in Financial Planning at University of Stellenbosch Business School , Bellville, graduating in 2015. So with all that and my years of winemaking  I think I am fairly well qualified to do what I am doing !” Then adds, “ Making wine and running my own business.”

Q. Do you consider your approach to winemaking to be different to others ?

“Not really. I am very involved  during all of production process. I am well organised and very particular on cleanliness in the wine cellar. I stay away from any possible oxidation, and believe that less is more . If the wine was handled well and the process well controlled, no additions will be needed. I like to get everyone involved and believe that hard work is always well rewarded.”

Q. How involved to you get in the vineyard ?

“We have a very experienced Viticulturist , Marius Cloete, with who I communicate on a daily basis regarding any developments in the vineyard .”

Q. Do you have any varieties you prefer to work with ?

“Yes, quite a few !  Chardonnay, Merlot, Sauvignon blanc and Cabernet Sauvignon.”

Q. Have you been influenced by any particular winemaker or by a wine region ?  

“I look up to plenty of winemakers in South Africa . It is not an easy career to be a winemaker, and doing it with success takes an enormous amount of sacrifice.”

Q. What would you consider to be your greatest achievement as a winemaker ? 

“I havn’t got there yet but one on my Bucket List would be the prestigious  General Smuts Trophy for the best wine at the annual National Young Wine Show. I admire and respect the long tradition of that trophy  and must also include the Veritas Wine Awards.”

Q. What “secrets” have you “developed”  that makes your wines different to others ? 

“I guess every winemaker has a secret that works for him/her. I don’t think I am any different but those are my secrets !”

Q. How important is modern winemaking equipment in your winemaking ?

“Modern equipment makes life easier, but the basics  still apply.  Clean ripe fruit. Minimal handling, minimum oxidation, minimum additions, good sulphur management and total involvement throughout. Then tasting, tasting and more tasting.”

Q. What about you and the future ?

“Since finishing my BSc in 2004 I have had 13 years of quality experience in the world –wide industry. Seeing as that I am only 35 I have lots still to do. Winning several awards at top competitions  as previous head of winemaking at Anura Vineyards (10 years) and then head winemaker at Glen Carlou I have earned a vast amount “know how” in the making  top end wines  and with this keeping  in touch with the important understanding of local and foreign consumer needs.” Then after some thought, continues “I have a long background in primary production of wine coming from a family owned fruit and wine farm in Calitzdorp. Involvement in the vineyard  has been a crucial part of my success with excellent  results and experience  in sourcing of good wine grapes.”

Q. What do you think has made you so well organised ?

“I think going to Oakdale Agricultural High engraved the organisation and helped in forward thinking” After some more thought “I have been interested in winemaking  from a kid and I guess some competition from my sister who is also a successful winemaker.”

Q. To finish ?

“Apart from my academic  achievements I have good practical and communication skills combined with ability to work hard and thoroughly and perform under pressure. One of my top attributes is to be always well organised and have confidence in myself.”

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Gone with the Wine: The Great Wine Love Affair

Wine is the ex-boyfriend I will never get over. My first love if I may be so bold. I met him when I was barely 18. I was old enough to want to get to know him and to prove to myself that I had progressed from the cocktails and ciders of my underage drinking youth. But, I was young enough to ignore all his flaws and too stubborn to admit it.

He was sweet. Sickly sweet. He made me giddy and reckless, and to be honest he always left me with a headache. Blushed and looking at him with rose-tinted glasses I was blissfully happy. We only met out in clubs and bars where the atmosphere was frivolous and care-free. It was a tumultuous relationship. Each time I woke up with a pounding headache and skin littered with blemishes from the sugar, and I swore it would be the last. But how could I write off the fun times I had had? For every morning plagued with hangovers, was a night filled with happy stories and memories that made my heart swell.

But alas, it was a love that could not survive the test of time. After one too many headaches, disapproval from my family and the promise of something new I broke off all ties.

As with any break up the time that followed was filled with ups and downs. The “ups” consisted of the excitement of new wines – why not try a fruity Sauvignon blanc, a flirty Chardonnay or… maybe even the bold and robust Cabernet Sauvignon rumoured to steal everyone’s heart. But with any great love story there was the inevitable “down”, the retreat. A late night out in town and I found myself with a glass of a sickly impersonation of the wine I once loved.

Except, it doesn’t taste quite as good anymore. Sure the memories are there and I can appreciate it for what it once meant to me. But we have both moved on. The sugary affront does not agree with me and I insult him disguising his flaws with ice and mixers. He remains the fun easy-going wine to be drunk by those not looking for commitment. They have come to experience wine without the work that is required to go into a mature relationship. I, however, have moved onto wines which I can introduce to my parents, I can eat meals with them and can take them to celebrations with friends.

With this knowledge I was inspired to try even newer and bolder wines. With my friends encouraging me and my peers guiding me I stumbled across my first grassy Sauvignon blanc. A summer love affair. A transitional wine as I refer to it now. It helped me move past my alliance to the sweet rosés. But winter came too quickly and I had to progress to richer red wines. Full of body, young fruits and the hint of mocha chocolate, they kept me warm at night. Once again I was drunk and rosy cheeked with infatuation. But something was still off. These wines lacked the depth and balance I was looking for.

So again I had to grow. I stumbled from these entry-level wines and learnt to look deeper. I stopped taking a wine for its label and fancy descriptions. I got to know them for who they were and what they had been through. I discovered the bolder wines, wines which have aged and matured. They are not dominated by fruity flirtations or cool, but somewhat overwrought, oak-y personalities. These wines have been developed and hid more beneath the surface. The subtleties are often missed and they are appreciated by few.

By now my heart no longer belongs to just one. I have pledged allegiance to Bordeaux blends, but I could never say farewell to my flamboyant champagne, nor could I turn away a sneaky Sauvignon or even some dominating Cabernet. I am committed to Chenin but I could never stray from Syrah. And my heart longs for Riesling but I can be persuaded with a Pinotage.

I am older and wiser. I have learnt what I do not like and what I do, the body, the character, the aftertaste. I have developed along with the wines, together we grow and mature. But in every new, complex wine I endeavour there will always be the faint memory of where I started. And sure enough, the next day the headache will return. Just as it always did when I was young and 18 and drunk off my first wine.

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Deacidification with Malolactic Fermentation

Malolactic fermentation (MLF) is a common processing technique used to biologically convert the malic acid to lactic acid and carbon dioxide (Krieger 2005). The conversion of malic to lactic acid is considered a deacidification technique. MLF is conducted through proliferation of native lactic acid bacteria (LAB), of which the three existing genera in wine are Lactobacillus, Oenococcus, and Pediococcus (Krieger 2005, Iland et al. 2007), or by inoculation of commercial LAB strains. The process of MLF has several chemical and sensory alterations to the wine (Waterhouse et al. 2016):

  • Decrease in titratable acidity (TA).
  • Increase in pH.
  • Decrease in sourness of the wine.
  • Potential development of the “buttery” aroma or flavor due to increased diacetyl production.

Commercial strains, Oenococcus oeni, are often preferred as this strain of LAB best conducts MLF (Waterhouse et al. 2016). O. oeni is relatively predictable in its ability to convert malic to lactic acid, and several commercial strains have various capabilities of producing the byproduct, diacetyl. Diacetyl gives rise to a buttery flavor or aroma that is desired in some styles of wine, such as oak aged Chardonnay.

When to Inoculate for MLF

LAB inoculation can be integrated into wine processing at several stages of production:

  • Before primary fermentation,
  • During primary fermentation,
  • Near the end of primary fermentation,
  • After primary fermentation is complete (Iland et al. 2007).

Each stage in which LAB can be added to the wine will offer a number of advantages and disadvantages to the winemaker. Ultimately, when LAB inoculation occurs can affect wine quality.

When winemakers add LAB to the wine, if desired, is a stylistic choice by the winemaker. There are some styles of wine that may not require MLF (e.g., unoaked Chardonnay), integrate partial MLF (e.g., sparkling wines), and others that encourage a full conversion of malic acid through MLF (e.g., many red wine blends). In cooler grape growing regions, the utilization of MLF is a natural deacidification process that can help decrease the perception of acidity, or sourness, in the wine. Malic acid, the primary acid affiliated with apples, has a much harsher taste than lactic acid, the primary acid in milk. In general, most American consumers tend to enjoy wines with moderate acidity (Krieger 2005), and MLF may be a practical tool to manipulate the wine’s acidity and stability.


Malolactic Fermentation (MLF) is a biological conversion of malic acid (the organic acid associated with the taste of apples) to lactic acid (the primary acid associated with milk). This conversion softens wine sourness perception and manipulates the acidity content. Photo by: Denise M. Gardner


Native or Spontaneous MLF

Additionally, some winemakers opt to utilize the native LAB to undergo MLF, though this can be unpredictable and tricky. Some wine processing techniques, such as juice clarification, can aid in the removal of native LAB and inhibit an adequate biomass of cells from forming to undergo MLF (Krieger 2005). Furthermore, some strains of native LAB can give rise to off-flavors or spoilage characteristics that may degrade wine quality.

Factors that Inhibit LAB

Nonetheless, even when using commercial strains of LAB, MLF can offer several challenges to winemakers. MLF is not always easy to complete efficiently. Several factors can contribute to a sluggish or stuck MLF including:

  • Inhibition by sulfur dioxide, alcohol, temperature or oxygen.
  • Inadequate nutrition.
  • Competition from other microorganisms (e.g., acetic acid bacteria, native LAB).
  • Presence of copper ions or residual pesticides (Iland et al. 2007).

A stuck MLF can be a difficult winemaking situation. Wines are usually left unprotected with very little sulfur dioxide in the wine. Additionally, wines are usually maintained within the ideal LAB growing temperature, around 68°F. However, this warmer temperature is also ideal for a number of potential spoilage microorganisms to grow. Warm temperatures and a lack of adequate antimicrobial protection offer ideal conditions for growth of spoilage microorganisms.

How to Monitor MLF

Many wineries find it affordable and convenient to monitor MLF progression through paper chromatography. Both Enartis USA and Midwest Supplies offer decent protocols for paper chromatography that are available online and free.

However, to ensure that your MLF is completed, it is best to use enzymatic analysis to determine the concentration of malic acid and lactic acid in your wine. While this analysis can be completed in a winery’s lab with access to a spectrophotometer, proper pipettes, and an enzymatic kit, wines can also be submitted to a commercial wine lab for completion confirmation.


Only a small sample is required to monitor MLF by paper chromatography. Photo by: Denise M. Gardner



Iland, P., P. Grbin, M. Grinbergs, L. Schmidtke, and A. Soden. 2007. Microbiological Analysis of Grapes and Wine: Techniques and Concepts. Patrick Iland Wine Promotions Pty. Ltd. Australia. ISBN: 978-0-9581605-3-7

Krieger, S. 2005. The history of malolactic bacteria in wine. In Malolactic Fermentation in Wine: Understanding the Science and the Practice. Lallemand, Inc. Montreal, Canada. ISBN: 0-9739147-0-X

Waterhouse, A.L., G.L. Sacks, and D.W. Jeffery. 2016. Understanding Wine Chemistry. John Wiley and Sons, Ltd. United Kingdom. ISBN: 978-1-118-62780-8

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Meet Corlea Fourie – Winemaker at Bosman Vineyards

Q. When and where were you born ? 

“1980 in Johannesburg”.  “However my Dad moved the family to Bloemfontein and I grew up and went to school there.”

Where did you study ?

“I did a Bsc Agric Oenology at Stellenbosch University and I was in the class 2003.”

Q. Do you consider your approach to winemaking to be different to others ? 

“I know I have many wine friends that feel the same way about certain things we do but then our approach is personal.”

Q. How involved do you get in the vineyard ? 

“As I work for one of the most prominent vine nurseries in the Southern Hemisphere I am surrounded by an amazing viticultural team.  I’m responsible for vineyard to wine goal outcomes so I do try to get to the vineyards as much as possible. That said, it’s still something I have to work at. There is always something pulling me away!”

Q. Do you have any varieties you prefer to work with ?

“Chenin blanc is my very dear favourite!  Some people consider me to be a chenin junkie!””

Q. Have you been influenced by any particular winemaker or by a wine region?  

“After visiting the Loire I have picked up a touch of sentiment for the valley.  Many winemakers have influenced my thoughts on wine, here and abroad.  Wine is, to some extent, a social experiment with so many tastes and thoughts.  It is dynamic. ”

Q. What would you consider your greatest achievement as a winemaker ?

“Achievements are dynamic too. You are measured by your consumer’s pleasure by the wine in the glass. Every season brings new challenges and opportunities.”

Q. What “secrets” have you “developed” that make your wines different to others ?

“No secrets. I have a young team who work with me and madness in their methods are freely shared. I do try, and do have a soft touch though.”

Q. How important is modern winemaking equipment in your winemaking ?

The answer is straight and to the point. “It is.” And continues “We do not need to work harder but smarter. Modern equipment usually helps with this.”

Q. How did you come to be at Bosman Vineyards ?

“I had been doing some consulting work in the area and came across Petrus and we were both making small batches of experimental wines on a neighbouring farm.  He was busy in renovating a 250 year old cellar on his family farm and Petrus invited me to join him. It was like a dream come true although we struggled to figure out how to use all the equipment! Hard to believe that is ten vintages ago!  In that time we have made some great wines.”

Q. In general ? 

“Although growing up mainly in the Free State with no vineyards in sight I spent family holidays in the Cape Winelands where my elder sister lived. After finishing school and doing a “Gap Year” mainly in the hospitality industry, I started my studies. I was prompted by my love for biology and science which led me into wine. I did a harvest as a practical and this introduced me to my future husband who was the winemaker at the farm of my choice!   We are now raising a family with a twelve year old daughter and a pigeon pair of twins aged seven.   I look forward to achieving my personal goals as a winemaker whilst working in a dynamic industry.  Lots of good stuff to look forward to. “

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The Grape Fun of Harvest

March 2017, my very first harvest. As a student, you never quite know what to expect beyond your textbook, and so when our harvest finally started, we all eagerly queued up in the minute cellar beneath the JH Neethling building, not quite knowing what challenges awaited us. To be honest, we were thrown in the deep end, but I’ve come to learn that knowing how to swim is an important skill to have in the cellar.

With our Felcos and refractometers at the ready, we were set loose on the poor Welgevallen vineyards. I don’t think anyone was quite as enthusiastic to wake up at 5am (to take the routine ballings) as I was during that period. I was adamant that our group had to be in the vineyard to take readings while it was still cool in the mornings, and so by 6 we were ready to sample our rows and get a grip on our harvest. I don’t think the other group members quite enjoyed me pointing out that there was a possibility that a few of the grapes we’d been tasting more than likely contained a bit of an extra protein factor (worms, bugs etc).

You’d think that the enthusiasm would have worn off after week 1, but I ended up spending my weekend work shifts begging my bosses, at a boutique winery, to let me help out with punch downs too. This is where things got a little bit more interesting and a whole lot messier.

The plastic fermenters were just a little bit too tall for me to use the pigeage (punchdown) stick, initially I decided to only use my hands to do the punch downs (with help from the tasting room manager and one of the winemakers). I quickly came to the realisation that the customers (I am a wine steward) might not take to my now purple stained fingers, hands, arms, elbows…you get the idea. I then had the very bright idea to climb on top of the tanks, that had a rim thickness of only 5 cm. But wait, the cellar antics and health and safety infringements don’t stop there, I was wearing open sandals with no grip – yikes!

After boosting myself on top of the tank, my boss handed me the punchdown stick and I proceeded to break through the bubbling shiraz pomace at a steady pace. Not long after, I realised that there was a cooling plate in the tank, and so I thought, “Hmm, no problem, I’ll just press down lightly until I just touch the plate”. Just as I leaned in, my boss decided to move the cooling plate, and all I could see was certain death flashing before my eyes. In all honesty, there are worse ways to go than falling into a big tub of wine. After flailing in mid-air for what felt like a few seconds, I managed to grab hold of a thin hook that just happened to be perfectly positioned on the wall behind me. With only two fingers, I managed to pull myself up.

I would have been slightly more shaken if the tanks were slightly taller and fuller – in reality I could probably have just stood up, had I fallen in. What did I say earlier about learning how to swim?

So, after an interesting weekend in the cellar, I made my way back to Stellenbosch (to be in the department’s cellar). After telling one of the experimental winemakers, Edmund, about my weekend’s antics, he made 100% certain that I was always wearing my cellar boots, whether I had decided to rock it out in my gumboots and a sundress or hippy pants, he would spot me from the moment I set foot into the cellar. On one occasion, I was not wearing my boots and my dreaded sandals made a reappearance. I thought I could get away with only doing lab analyses that day, but alas! – I was caught red-handed and promptly reminded of the importance of wearing closed shoes in the cellar. The other winemaker, Marisa, threatened to throw things at the students’ toes if she caught our feet armed with anything other than closed, non-slip cellar boots.

Although my sandals didn’t make a reappearance, my hippy pants definitely did. I now call them my grape pants, because they’re grape to wear… pun intended. Pressing red grapes (merlot) while wearing lightly coloured pants, leaning over the little press and getting elbow deep into grape skins, while you’re supposed to be monitoring and adjusting the press’ pressure is not the smartest thing to do. The pressure on the grapes was just a little bit too high, causing berries to rapidly pop (explode) rather than lightly being crushed and squeezed. The other group members and I ended up looking like we had just facilitated a berry genocide, with gory bits and pieces of grapes and deep red juice splattered all over ourselves! Needless to say, the grape hippy pants were covered!

After two cellar mishaps in one week, one of my lecturers suggested that I leave these stories out of my harvest internship interviews. Although I ignored this advice (made for an interesting interview), I am now a reformed cellar-mishap-maker and have decided to take health and safety hazards a little more seriously, but I can’t promise that the hippy pants won’t make a grand come-back!

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