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New World Wine Maker Blog

Winter Cold Damage Revisited

By Bryan Hed from Wine & Grapes U.

Since the new year was ushered in we have had several scary moments when Mother Nature unleashed an “excess of personality.” I’m referring to the cold weather events we experienced around January 1, 7, and 14, when temperatures slipped down below zero in many places across Pennsylvania, even in some south central parts of the state. As many of you might remember, the last time we saw below zero temperatures that far south (February from hell, 2015) primary bud damage was widespread and grapevine trunks in vineyards all over Pennsylvania (and certainly other parts of the Northeast) exploded in crown gall the following spring. This generated a two-year trunk renewal process that we’ve only just recovered from. Therefore, this may be a good time to review grapevine winter hardiness and the factors that affect it, as well as how we can prepare for possible remediation pruning and renewal this spring.

Now I don’t want to raise alarm bells just yet, as the conditions we’ve experienced this January haven’t been as horrific as February of 2015. But it’s always good to be prepared for any potential consequences, like bud loss and trunk damage, so we can anticipate altering our winter pruning plans and production practices this season.

Let’s start with a review of the temperature stats available to everyone on the NEWA website (newa.cornell.edu) and see just how cold it got in various places across the state during the first half of January. In the table below, I’ve listed low temperatures for January 1, 7, and 14 for many of the NEWA locations. Starting at northeastern PA and moving counterclockwise to swing back up into northern New Jersey and finally western New York, we get the following data (Table 1).

Screenshot 2018-01-20 07.11.38

Areas of southeastern and northwestern Pennsylvania, at opposite corners of the state, appear to have escaped the below-zero temperatures for the most part, but some areas of south central Pennsylvania took a hit (look at York Springs). Areas of southwestern Pennsylvania experienced some of the most extended periods of below-zero weather, and parts of northeastern and central Pennsylvania also got quite cold. The temperature low is the most important bit to consider when sizing up vine bud damage, but the duration of those lows can affect the extent of trunk damage, especially in big old trunks where it may take longer for the core to reach ambient temperatures. Up in the northwestern corner of the state, the buffering effect of Lake Erie probably played a role in our relatively mild temperatures during that period, and we expect little to no damage to most of our vines as our wine industry there is heavily invested in tougher hybrids. The Erie area was also blessed(?) with a heap of snow (10 feet!) before the cold snap that provided added protection to bud unions of grafted vines.

If you’re anticipating primary bud damage, here’s a review of the ranges of temperatures for the LT50 (low temperature at which 50% of primary buds fail to survive) for the cultivars you’re growing. For Vitis vinifera, the LT50 range of the most winter sensitive cultivars falls between 5o and -5oF. This includes cultivars like Merlot and Syrah. But for most cultivars of V. vinifera, LT50 values fall more in the 0o to -8oF range (Chardonnay, Cabernet Sauvignon, Pinot gris, Pinot noir, Gewurztraminer). And finally, there’s the tougher V. vinifera and sensitive hybrids that have buds with LT50 values of -5o to -10oF. This includes cultivars like Riesling, Cabernet franc, Lemberger, and Chambourcin. On the flip side, most hybrids fall into the -10o to -15oF range (which is why Northeastern U.S. vineyards are perhaps still more invested in hybrids than V. vinifera). Then there are the V. labrusca (Concord) and the Minnesota hybrids that range from -15o down to -30oF for cultivars like Frontenac and LaCrescent. Unfortunately, we don’t have such helpful ranges for determining trunk damage, which often comes with more profound consequences and is costlier to address.

Rapid temperature drops are often the most devastating in terms of the extent of damage. Fortunately, December temperatures this winter descended very gradually giving vines time to fully acclimate to cold weather extremes. In fact, recent data from the Cornell research group in the Finger Lakes region of New York shows that LT50 values for primary buds of several cultivars were close to, or at, maximum hardiness. Therefore, it is hoped that many Northeastern U.S. vineyards were well prepped and close to their hardiest when these cold events occurred. On the other hand, any given cultivar in central New York is likely to be a bit more cold hardy than that same cultivar growing in southern Pennsylvania, simply because vines farther north will have accumulated more cooling units than those farther south. So there is the possibility of bud and—worse yet—trunk damage in parts of PA, to the more sensitive cultivars of V. vinifera.

We also had a balmy warm period during the second week in January that pumped temperatures up into the 60s in some places before plunging back down into single digits. However, it’s unlikely the brief warm period was long enough to cause any deacclimation of vines before cold temperatures resumed, and little, if any harm, is expected from that event.

The capacity for cold hardiness is mostly determined by genetics. As I alluded to above, V. vinifera cultivars are generally the most sensitive to cold winter temperature extremes, French hybrids are generally hardier, and native V. labrusca cultivars are often the toughest. Nevertheless, other site specific factors can come into play to affect cold hardiness, and this is often the reason for the range in the LT50 values. For example, there’s vine health to consider; vines that finished the season with relatively disease-free canopies and balanced crop levels can be expected to be hardier (within their genetic range) than vines that were over-cropped and/or heavily diseased. At times like these, we can’t emphasize enough how important it is to maintain your vines and production strategy with a view to optimizing their chances of surviving every winter. Other stresses like drought or flooded soils (during the growing season) that we can’t do much to control, and infection by leafroll viruses, can also play a significant role in reducing vine cold hardiness.

If you suspect damage, you should delay winter pruning of your vines, according to Dr. Michela Centinari. Feel free to revisit her previous blog posts and others at psuwineandgrapes.wordpress.com. Type “cold hardiness” or “winter injury” into the search box, and you’ll quickly and easily gain access to several timely blogs.

Bud damage can be estimated from 100 nodes collected from each potentially compromised vineyard block. Typically, gather ten, 10-node canes from each area, but do not sample from blocks randomly, unless the block is relatively uniform. If a block is made up of pronounced low and high areas (or some other site feature that would affect vine health and bud survival) make sure you sample from those areas separately as they will likely have experienced different temperature lows (Zabadal et al. 2007). You may find that vines in high areas need no or less special pruning consideration than vines in low areas that suffered more primary bud damage and will require increased remediation.

Once you have your sample, bring the canes inside to warm up a bit and make cuts (with a razor blade) through the cross section of the bud to reveal the health (bright green) or death (brown) of primary, secondary, and tertiary buds. You’ll need a magnifying glass to make this determination as you examine each bud. You should figure that primaries will contribute two thirds of your crop and secondaries, one third when considering how many “extra” buds to leave during pruning. And remember that some bud damage, up to 15% or so, is normal. If you’ve lost a third of your primaries, leave a third more nodes as you do your dormant pruning. If you’ve lost half your primaries, double the nodes you leave, and so on. However, when bud mortality is very high (more than half the primary buds are dead), it may not be cost effective to do any dormant pruning as it is likely there are more sinister consequences afoot, like severe trunk damage that is much harder to quantify. A “wait and see” strategy, or at least very minimal pruning, may be best for severely injured vines (Figure 1) and trunk damage will manifest itself in spring by generating excessive sucker growth (Figure 2). And one more thing: Secondary buds are often more hardy than primaries, may have survived to a larger extent, and in some cultivars, can be incredibly fruitful. This is especially true of some hybrid varieties like DeChaunac. So, to make more informed decisions when winter damage is suspected, you have to know the fruitful potential of your cultivar; and in cases where primary bud mortality is high, it’s therefore important to also assess the mortality of secondary buds.

Screenshot 2018-01-20 07.07.06.png

Another great fear is the appearance of crown gall, mainly at the base of trunks. This disease is caused by a bacterium that lives in the vine. However, the bacterium generally doesn’t cause gall formation on trunks until some injury occurs, usually from severe winter cold damage near the soil line or just above grafts on grafted vines (if you hilled over the grafts last fall). Another search at psuwineandgrapes.wordpress.com will bring up information on how to deal with this disease.  You can also visit What we have learned about crown gall for an update on research into this disease from Dr. Tom Burr and his research group at Cornell University. Tom has devoted a lifetime to researching grape crown gall and many advances have been made over the years. But it’s still a huge problem for Northeastern U.S. grape growers; and crown gall problems will likely increase as our industry becomes more and more heavily invested in the most susceptible cultivars of V. vinifera.

With more sensitive detection methods, Tom’s group is getting us closer and closer to crown gall-free mother vines and planting stock, but they’re also discovering that the crown gall bacterium is everywhere grapevines are located. Not restricted to internal grapevine tissues; it’s also found on external surfaces of cultivated and wild grapevines. So, clean planting stock may still acquire the pathogen internally down the road and management of crown gall, once vines are infected, will continue to be an important part of life in any vineyard that experiences cold winter temperature extremes. However, there is potential for a commercial product that inhibits gall formation, which can be applied to infected vines. The product is actually a non-gall-forming, non-root-necrotizing version of the crown gall bacterium that is applied to grape wounds and inhibits the gall-forming characteristic of the pathogenic strains of the bacterium. This product is still under development in lab and greenhouse tests, awaiting field nursery trials soon.

If you do happen to meet up with some crown gall development this spring, galled trunks can be nursed through the 2018 season to produce at least a partial crop while you train up suckers (from below the galls) as renewal trunks. When our Chancellor vineyard was struck with widespread crown gall in the 2015 season, we were able to harvest a couple of decent sized crops while trunk renewal was taking place (Figure 2), and we never went a single season without some crop. There’s also the issue of crop insurance to think of; adjusters may want you to leave damaged trunks in place so they can more accurately document the economic damage from winter cold.

Screenshot 2018-01-20 07.07.34

Lastly, a great guide to grapevine winter cold damage was published about 10 years ago by several experts. In fact, information from that guide was used in composing large parts of this blog and I highly recommend you read it. It’s an excellent publication, the result of many years of outstanding research by a number of leading scientists and extension specialists from all over the Northeastern U.S. The details of that publication are found below and you can purchase a hard copy for 15 bucksby clicking here: Winter Injury to Grapevines and Methods of Protection (E2930).

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MEET ARCO LAARMAN – OWNER WINEMAKER LAARMAN WINES

Q. When and where were you born ?

“I was born far from the Cape and it’s vineyards. In a place called Roodepoort, not too far from Johannesburg. My mother gave birth to me on January 9th, 1977.”

Q. Where did you study ?

“I did not go to a university but learned my Trade as an apprentice ! I had wanted to be a winemaker since I was about 12 years old.  I matriculated in 1995 and my mother suggested I do a harvest first, to make sure that I wanted to be a winemaker. My first harvest was with the great Danie Steytler on Kaapzicht.” After some reflection he continued “ I ended up staying there for four harvests , and within those short four years  I also worked for Mobott (a mobile bottling company for eight months. Not only enormously valuable experience but it was a good way of meeting people in the wine industry. You would be surprised how many wineries there are that the average person never get to know about.” He continued “We had done some bottling for Glen Carlou and in the middle of 1999, David Finlayson offered me a job as an assistant winemaker, which I gladly accepted. Before starting at Glen Carlou I had enough time to do an American harvest. David organised a  position for me at The Hess Collection Winery in Napa Valley, California, where I worked for four months. In 2000 I went to France for a harvest in Beaujolais where I was for about four weeks. I also completed a harvest  in Australia in 2003 at Xanadu Wines in Margaret River. I also worked at friends  wineries in Austria and Germany. I spent 17 years, in all, at Glen Carlou and left in 2015 to start my own venture.”

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

“Since leaving Glen Carlou my approach has changed and I work my brands  from different regions as I sell my wines  as me being the endorsement  of the wines as I am person and not an estate that one can visit. So I take varieties that work best in the selected regions.”

Q. How involved do you get in the vineyard ?

“I am very involved with all the owners  of the vineyards I buy grapes from and work together with their vineyard managers to secure the best fruit possible.”

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

“I believe in the noble varieties as they will always sell but I regard  myself as a Chardonnay specialist with my 17 years at Glen Carlou. I also work with Cabernet Sauvignon, Cinsaut and Chenin Blanc. That is for now but there are sure to be more in the future !”

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

“Having worked with David Finlayson for over ten years be fore he left Glen Carlou I would say he and Danie Steytler of Kaapzicht were great people to have learnt from. I have only dealt with Paarl grapes  for 17 years  but now on my own I am excited  to now work with grapes from Piekernierskloof , Vermaaklikheid, Stellenbosch and Elgin.”

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

“My long standing career with Glen Carlow and the accumulation of awards in those years . However, I don’t make wines with the idea to achieve awards.”

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

With a broad grin “It would not be a secret if I told you”. “ However I can share that wine is only as good as the fruit you  work with and then no need to overwork wines in the cellar.”

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

“Not that important. You must have healthy fruit and then hygiene is very important as well as protection from oxidation.”

Q. What of the future ?

“My first release on my own is the “Cluster Series” includes a Chardonnay and a Cabernet Sauvignon and there will be more to follow.”

Q. Why have you called your wines The Cluster Series

“This has been my way of bringing together quality grapes, my winemaking experience, my family and friends in the industry. Not only is a cluster a bunch of grapes but it is a constant reminder that none of us can succeed in isolation. One grape cannot make a bottle of wine !”

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More wine than water

In 2015, South Africa experienced the lowest levels of rainfall that had been recorded since 1904. Thus, making it no secret that the drought has run its toll on the economy and the environment. If we as humans, could cope with the drought as well as the grapevine can, then we would be having a much smaller problem. We may not possess the ability to turn water into wine, but we however, need to start researching ways to turn wine into water.

El Niño, which is labelled as the rise of oceanic temperatures in the South Pacific, is said to be one of the main causes of this massive drought. South Africa’s bipolar weather patterns has furthermore been affected by the change in global climate, which has ultimately led to the abnormally high temperatures across the southern tip of Africa.

Over the past year or so, this drought has had an immense impact on the South African agricultural sector, leading to a decline in production, livestock and finances. South Africa’s food security is also under threat, as summer crops have not been able to survive the decreased levels of winter rainfall.  Ultimately, farmers are looking for more solutions as water and grazing has become a huge issue for livestock, resulting in higher meat prices throughout South Africa.

In the midst of our doom and gloom, it is absolutely fascinating to see how well some parts of the wine industry is doing, considering the lack of water and moisture in the air. Vines have the most outrageous ability to perform under any given condition and can therefore be looked at as, the sweetest form of weeds, growing wherever they are planted, producing the most complex fruit that eventually gives as wine.

According to VinPro, the 2017 harvest overcame most expectations and delivered a harvest that was 1.4% larger than the 2016 one. This was due to cooler nights and relatively constant temperatures during the day, which had a soothing effect on the vines when it came to harvest time.

It seems like the corks will continue popping as wine drinkers will not be experiencing a drought after all. Stressful conditions can sometimes have a positive effect on the quality of grapes, if the vineyards are managed well enough. Farmers must be willing to go the extra mile, protecting the grapes against the suns extreme heat and applying water as cautiously as possible. A possible solution for farmers is Canopy management. Canopy Management can be a very labour intensive process, which requires a thorough knowledge of the cultivar and climate. However, the effect can be advantageous, as the spacing of leaves on a vine can protect the grapes and prevent loses in acids, flavour compounds and colour.

The large leaves found on vines, provide an excellent umbrella to shade the grapes from the sun. As in life, tough situations can sometimes have a very positive outcome. With applied stress in grapevines, the vegetative growth is neglected and all the reserves are optimized and channelled towards the greedy sinks of a vine. In other words, all the good stuff is produced by the greedy nature of the reproductive sinks in a grapevine.

A grape formed under stressful conditions can have a concentration of sugars and anthocyanins, which is the compound responsible for colour development in wine. I personally love our South African red wines, with their high tannin, full bodied form, providing us with the best natural lip colour that any woman can ask. South Africa is seen as a warm wine producing region, known for our full bodied, high tannin and deep coloured wines. Cooler regions, such as France and Germany, produce wines with a higher acidity, lower tannins, with a light ruby colour form.

Under optimal conditions, leaves can get lazy. This can come in the form of, vine leaves not contributing to the process of photosynthesis. During harsh conditions and high radiation, the sun causes the outer leaves of the canopy to shut down over lunch time. During this time, the radiation is too high for the leaf to withstand the heat and causes the leaf’s stoma to close. It is then up to the shaded leaves deeper in the canopy to produce photosynthetic products that will ultimately keep the vine alive. Thus, allowing the grapevine to deal with high sunlight exposure and water stress on its own.

During this significant drought, our wine farmers have been pushed to the brim. Winemakers have been challenged and have had to look for new methods to help sustain vineyards and find a perfect balance between quality and quantity. Vines found in regions like Breedekloof, Stellenbosch and Worcester delivered a smaller harvest, but wine of a high quality.

At the end of the day, wine lovers can sleep well at night as the hardened nature of grapevines and the innovative management practises of viticulturists and winemakers, provides us with high quality wine that can drive us through this tough period. Needless to say, this drought is a huge problem, and we should do everything in our ability to try and keep our water usage as low as possible.

Be sustainable and drink a glass of wine instead.

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Let’s Talk About Appassimento Wines

What is ‘Appassimento?’

Appassimento is a wine processing technique in which harvested grapes go through a drying process prior to fermentation. This process is used traditionally in Italian wine regions to make the popular Amarone, Recioto, Valpolicella Ripasso, and Sforzato wines.

Appassimento influences the flavor and concentrates sugars in dried grapes. This results in flavor and mouthfeel alterations in the wines that use grapes dried by appassimento methods. As the sugar concentrates, through water evaporation, wines produced from dried grapes may result in higher alcohols. Flavors becomes more rich and bold, adding complexity to still wines.

 


This appassimento-style wine is produced at Barboursville Vineyards in Virginia. Photo by: Denise M. Gardner

 

Why is “Appassimento” of Interest to U.S. Wine Regions?

In the last few years, I have noticed appassimento techniques implemented at a number of wineries across the U.S. and Canada.

While many may assume appassimento grapes could be used for dessert wine production, this technique can also be applied to dry wines. Like hanging grapes out on the vines during the coldest winter months, appassimento is a concentration technique.

In the East, we often discuss primarily two ways of improving still, red, dry wines:

  1. Enhancing extraction of grape constituents during production, and
  2. Improving the concentration of desired characteristics like flavors, aromas, sugar, tannins, and polysaccharides (long-chain sugar compounds that improve viscosity and softness of a wine).

Winemakers often use methods like cold soaking or extended maceration to enhance extraction of grape constituents. Additionally, using tools like rotary fermenters can help improve extraction by extending juice/wine contact time with grape skins.

In contrast, improving concentration requires different winemaking strategies. Extended hang time, to concentrate sugars and ripen flavors could be viewed as a concentration technique. The presence of Noble Rot concentrates sugars and flavors. The use of reverse osmosis, especially when applied to juice, is a concentration technique that removes water. Flash thermovinification, in some respects, is a concentration technique that can alter flavor and mouthfeel characteristics of wine. All of these methods help minimize the influence of unripe characteristics (i.e., usually green aromas). In some cases, sugar levels may be concentrated as well.

The drying process associated with appassimento evaporates water from the grape berries, concentrating sugars. Additionally, the drying alters primary flavors that will be passed onto the wine. Some of these flavors may appear more “ripe” in their description. Common sensory descriptors for appassimento grapes include: prunes, raisins, dark fruit, black fruit, honey, dried violets, and dried fruit.

When applied appropriately, such grapes can transform a still red wine with fresh red fruit characters into a bolder, richer wine.

How Can I Integrate Appassimento into My Winery?

The use of appassimento requires careful planning, specifically for where and how grapes will be dried. Traditionally, in Italy, drying houses can be complex. Environmental parameters like temperature and humidity are controlled. Pest control and spoilage are important factors that are routinely monitored.

Recent research in Canada, through the Cool Climate Oenology and Viticulture Institute (CCOVI), has looked at alternative drying methods including use of:

  • On-vine hang time,
  • Barn drying,
  • Drying chambers,
  • Greenhouses, and
  • Kilns.

Other industry members in Virgina have used old toacco barns for drying grapes.

 

If you have an interest in appassimento wines, we’ll be discussing this topic at the 2018 Wine and Bev X Conference in Washington D.C. (February 21st). [Use the promotion code, DGWINE, to receive 50% off your registration.] Attendees will be fortunate to hear from Luca Paschina, winemaker at Barboursville Vineyards (Virginia) who has many years of experience been making wine from appassimento grapes. For those that have not previously been to the winery, there is an appassimento drying house on site, emulating the traditional Italian process. The Barboursville Vineyards Paxxito (Malvaxia) was one of the first U.S.-produced appassimento-styled wines I tasted. Using Moscat Ottonel and Vidal Blanc grape varieties, it is truly an unique wine with a lot to offer. I have always enjoyed its pairing with dessert at the Barboursville Vineyards on-site restaurant, Palladio.

In contrast, winemaker Sean Comninos from William Heritage Winery (New Jersey) will discuss production of his first red appassimento-style wines. Sean will bring insight and contrast to Luca’s rich experience integrating appassimento techniques into the winery. I look forward to delving into all that Sean learned during the first year of his wine’s production.

If you have followed up with previous blog posts, you know that Dr. Debra Inglis and Michael Jones will also join this session. Both of them bring a plethora of knowledge and technical details related to managing wine quality during appassimento and throughout production of the wine.

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Spies in the tasting room

The Scene: Picture an old black and white detective movie along with jazz filling the air, creating an atmosphere of intrigue and mystery.

Beware those who work in a tasting room, that group of students may not be as unstudied as they seem. Keep a look out for the students who analyse the tasting sheets and bring pens to tastings. Note that they might not be on WhatsApp but actually typing out notes on the wine or even on your presentation skills. Take caution, the students who practise correct wine tasting etiquette; they may have a secret. They may be wine students.

Wine students are received in two ways:  Tasting room assistants assume they know everything and thus give no information, or they bombard the students with technological information that baffles their companions.

Thus the mission was simple: blend in as a student without being identified as a wine student.

An attire of a smart-casual, no perfume or scent applied, a black pen discretely tucked into the coat pocket along with a neatly folded piece of blank paper. A reservation made for a group larger than three people, a driver drops the group off at the tasting room. The manager sees them, expecting the worst:  Students are here.  Sending over a tasting room assistant, the manager retreats, unsuspecting to the spy in their midst.

The tasting room assistant, trying to be upbeat, cannot hide disdain as students are notorious for ‘tasting’ a lot of wines and not buying anything. Leading them down the standard tasting route, the tasting room assistant tries hard to entertain the group, talking the usual small talk as the spy swirls the first wine in the glass. The legs drip down and re-merge with the pool of wine at the bottom of the glass. Sniffing it, the spy tries to stifle a grin, knowing that even though the tasting room assistant assured the group it was one of the farm’s best – it was the most standard, bottom of the range wine that the farm had to offer.  The spy lets the assistant off the hook for that one, after all one can’t be blamed for trying to make a sale.

The second wine is bought out, a pale pink rose’. Typical cotton candy and strawberry and cream on the nose, nothing special but none the less the spy continues to record the aroma analysis. The group seems to enjoy it, empty glasses spread over the table except for one. The spy will not finish their glass but rather throws it in the spittoon.  The spy looks around and decides to take photographic evidence, hurrying the group to take selfies in-front of an easy to recognise farm logo. Searching, the spy notices that the cellar is visible through glass windows in the tasting room, again the click of a photo being taken of the cellar. The spy is stealing with their eyes.

The group sits down once again, awaiting the wooded white wine. The tasting assistant comes over and spins a web about the wood making it buttery and how they used different types of oak to enhance mouthfeel, never once mentioning malolactic fermentation or the bacteria added to induce it. The spy smiles a knowing smile. Some of the group loves the wine; others dislike it, irrespective all the glasses stand empty after the wine has been ‘tasted’, all except one. Once again the spy pours the wine out into the spittoon after analysis.

Onto the red wine, the tasting room assistant pours out the last dregs of the bottle into the spy’s glass. The spy sniffs the wine: wet dog and very musty. Beckoning to the assistant that the wine is corked, the spy worries that their cover is blown. The tasting room assistant raises their eyebrow, sniffing the glass themselves; they apologize and retrieve a new bottle of wine. After the new round is poured the tasting room assistant retreats and observes how the spy analyses the wine. Suddenly it clicked; this student is no ordinary student:  this student is a wine student.

Trying to redeem the tasting; the tasting room assistant brings out a premium red blend.  Not making a fuss, the prestige is played off as a gift from the assistant. The spy knows their cover is blown, analysing the last wine knowing it would be superior to its predecessors; the spy sits back and enjoys the last glass. A full page of notes on the wine made and a record of the fame, date and assistants name was neatly folded back and placed in the spy’s pocket.

Never confirming whether or not the spy enjoyed the tasting experience, never confirming whether or not the spy enjoyed the wine, the group left with only the payed bill and a tip remaining. The spy walked ahead of the group, comparing and contemplating their experience to others experiences before, the mission was successful.

So beware those folks of whom work in a tasting room, there may be a spy in your midst.

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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.

>> CLICK HERE FOR FULL ARTICLE AND RESULTS

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