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New World Wine Maker Blog

July Pre-Harvest Planning in the Cellar

By: Denise M. Gardner

If you are a wine producer in the northern hemisphere, harvest may feel quite far away.  However, given that it is now the month of July, it will be here before we all know it.

Harvest season is just around the corner! Photo by: Denise M. Gardner

The month of July is a great time to start preparing a few essential pre-harvest tasks including getting a bottling schedule ready, especially if bottling operations have not yet begun, and ordering harvest supplies.   This blog post will focus on these two tasks.

Prepare and Enact a Bottling Schedule

New grapes are about to flood your winery with juice and future wine.  Now is the time to review inventory within the cellar and determine what has to be moved and what has to be bottled before harvest begins.

Freeing up previous years’ inventory by moving it into bottle will free up tank, barrel and storage space for this year’s incoming fruit.  It makes for a much easier transition if all of the wines that need bottling are bottled before harvest season starts.  Bottling during harvest is not only chaotic, but it tires employees, pulls resources from the incoming product, and may lead to harvest decisions that may be regretted later.

Always make sure to get bottled wines properly stored and away from any “wet areas” on the production floor.  If possible, bottled wines should have a separated storage area within an ideal environment that is physically separated from production.  From there, stored wines can be moved into retail space when needed.

For more information on how to get wines prepared for bottling, please visit our previous posts:

Bottling comes with its own set of challenges and risks, but several analytical tests can help put a winemaker’s mind to ease regarding bottle stability. Photo by: Denise M. Gardner

Ordering Fermentation and Lab Supplies

Many suppliers and wine labs offer free shipping in July, which can especially be useful for wineries that are not geographically close to a winery supply store-front.  Planning ahead and determining what fermentation supplies will be needed in August, could save extra money.  Not to mention, having supplies on hand during the busy processing season can be a big stress relief.

Winemakers should also take the time to look at new fermentation products and assess the previous year’s needs in order to adequately supply for the up-and-coming harvest.  Keeping an annual inventory of purchases can be helpful to isolate regular needs.

Things to consider purchasing include:

  • Yeast
  • Fermentation Nutrients
  • Malolactic Bacteria
  • Enzymes
  • Yeast Hulls
  • Salts for Acid Adjustments
  • Tannins
  • Pectic Gums and/or Inactivated Yeast Products
  • Fining Agents
  • Oak Alternatives or Barrels
  • Sanitizing Agents

While new yeasts are released frequently, being constructive about the production’s fermentation needs can help isolate what yeasts are needed for the upcoming harvest.  I typically recommend that all vintners have at least 5 strains on hand for harvest: 2 reliable strains that will get through primary fermentation with little hassle, 1 strain that can be relied upon for sluggish or stuck fermentations, and 2 strains for specialty needs (e.g., sparkling or fruit wine/hard cider production) or experimental use.

Select and purchase your yeast strains in July to take advantage of free-shipping promotions.

Fermentation nutrients should be a must-have for all wineries to help minimize the risk of hydrogen sulfide.  Always double check nutrient requirements for yeast strains purchased.  In general, wineries will need hydration nutrients (e.g., GoFerm), complex nutrients (e.g., Fermaid K), and diammonium phosphate (DAP).

For more information on why YAN is important and how yeasts utilize nitrogen during primary fermentation, please visit the following blog posts:

If you need further step-by-step instructions on how to determine adequate nutrient additions during primary fermentation, please visit our Penn State Extension fact sheet: Wine Made Easy Nutrient Management during Fermentation

Sometimes hydrogen sulfide will arise in a wine by the time primary fermentation ends despite all preventative care.  Making sure there are adequate supplies on hand, such as copper sulfate and PVI/PVP can save time in the future.  Also make plans for ways that the production can reserve fresh lees.  PVI/PVP is a fining agent that can help reduce metals like residual copper, but fresh lees will also help reduce the perception of hydrogen sulfide aroma/flavor and residual copper in the wine.  Having a plan for retaining and storing lees during harvest season can save time during challenging situations that develop through the end of harvest and into the winter’s storage season.  A fact sheet on copper screens and addition trials can be found at the Penn State Extension fact sheet: Wine Made Easy Sulfur-Based Off-Odors in Wine.

I also like to make sure we have supplies on hand in case of heavy disease pressure come harvest.  This includes things like Lysozyme, beta-gluconase, pectinase or other clarification enzymes, and fermentation tannins.  Lysozyme can help reduce lactic acid bacteria levels while beta-gluconase can assist clarification problems associated with Botrysized wines.  For further information on how to manage high-disease pressured fruit, please visit the Penn State Extension website on Fermenting with Botrytis or Managing Sour Rot in the Cellar.

Double check the storage requirements for all materials purchased before and after the product is opened.   It’s important to store all of those supplies in the winery properly as it will ensure their efficacy by the time the product is needed.

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Red or white?

Which is superior? “Red, obviously” says John Doe, 56, father of 3, and executive wine selection director of the weekly grocery run. “It has just got more too it. Unless it’s good, white wine is just cool-drink”. Thanks, John. Well, there you have it: a first-hand account from a made-up person designed to represent common opinion.

He/I does have a point, I should like to think. There is a general perception of red wine being the more bespoke of the two options. Look at most wine auctions and the most expensive is the big red wine. Speak to consumers and you may hear a chime of “I’m not much of a wine drinker, I only like whites because they’re light” or something from our friend John Doe’s line of rhetoric – an unsubstantiated claim that red wine is the connoisseur’s choice.

Perhaps white wine is more accessible, it certainly is lighter by the very nature of its production. It’s also served cool, or with ice, as if to imply it’s only a refreshment, and therefore, perhaps less of an acquired taste as red wine might be, as if red wine requires a more experienced drinker to appreciate. This only seems to apply from the point of view of an entry level wine drinker – and not one whom might participate on a wine auction, so this argument doesn’t seem to provide insight.

From a winemaking point of view, red wine production is the more interventionist of the two processes during the fermentation process, due to the skin extraction (skin-contact white wines are not participating in the argument today, sorry!). This doesn’t mean red wine is more difficult to produce, it is simply a technically unique production process. In fact, often the high flavour extraction and “oak-ability” of reds provides room to hide faults – smoke taint, for example – and could thus imply a larger room for error in red wine production, and therefore an easier job. This is simply one argument, not my universal opinion. It just provides a retort on the side of white wine.

Ageability could be the crux: reds seem to have an easier time aging, tannins providing timely rewards and oxidative protection. White wines, particularly in South Africa, need a delicate cellaring. Ironically, the average bottle of wine doesn’t make it 24 hours past purchase, let-alone into a viable aging cellar!

Personally, I believe it is the romance. Red wine is visually sensuous; it reminds us of Vatican paintings. It’s texture is fuller, and more alien to us, when recalling any other drink we may have had before. Everything about it is hedonistic, and we all, deep down, love that feeling. White wine seems to have lost out on the indulgence connotation, downgraded to red wine’s warm-up act, exiled to the domain of Gin and Tonic: a housewife (or husband’s) drink. Put in it’s context though, if you go to Germany – Riesling is king! Give me a line-up of 50 South African wines choosing one by cultivar alone, I’ll say “Chenin” without hesitation.

But what do I know, these are just the ramblings of a new world winemaking student still finding my way in the ‘Universe of Wine’!

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GMO yeast in wine and how to find them

By Erika Szymanski of the Winoscope

The vast majority of wine does not involve genetically modified organisms (GMOs). Let me repeat, the vast majority of wine does not involve GMOs. On to the rest of the story:

Whether wine contains genetically modified organisms (GMOs) is a question I’m asked often. In general, the answer is no. Genetically modified grapevines aren’t being used for commercial winemaking (though not for want of trying). Two genetically modified wine yeasts have crossed the commercial production threshold, but not worldwide. One, the un-charismatically named ECMo01, available only in the United States and Canada, has been engineered to produce an enzyme that degrades urea. That’s a useful property because urea in wine can become ethyl carbamate, which the World Health Organization thinks is probably carcinogenic enough to be worried about it.

The other, ML01 (which rolls off the tongue much more easily), is legal in the US and Canada as well as Moldova, and seems to have won more traction (though not, I dare say, because it’s available in Moldova). ML01 includes genes for two non-Saccharomyces cerevisiae proteins: a malate permease from fellow yeastSchizosaccharomyces pombe, and a malolactic gene from the lactic acid bacteria Oenococcus oeni. Together, those molecules allow ML01 to import malic acid into the cell and convert it into lactic acid, granting ML01 the rather magical ability to perform both alcoholic fermentation and malolactic fermentation simultaneously, all by itself. In addition to speed and convenience, this one-stop fermentation is advertised as a route to fewer wine headaches. Lactic acid bacteria can produce biogenic amines, which can produce headaches and other unpleasantries in sensitive people (I’m one of them); eliminating the need for those bacteria should eliminate the biogenic amines and those symptoms.

For reasons which are probably obvious, North American wineries using these GM yeasts don’t exactly go shouting that news from the rooftops, fewer headaches or not.

>> CLICK HERE TO READ THE FULL ARTICLE

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Meet Chris and Andrea Mullineux – winemakers and winery owners

Andrea is from California and met her husband to be on while working a vintage at Waterford. They then worked vintages in Europe and met on an excursion to Champagne while visiting a mutual friend.  They moved to South Africa and worked initially at Tulbagh Mountain Vineyards then with several Swartland growers and recognised the regions tremendous potential.  They opened Mullineux Family Wines in 2007 with the intent to focus on varieties they considered did best in the Swartland, Syrah and Chenin Blanc. Earlier in his wine days  in the Cape Chris had been involved in biodynamic techniques in  in vineyards and soon put this knowledge to work in the Swartland.  Andrea looked after the winery. Through minimal intervention she sought to highlight the uniqueness  of the Swartland soils in bottlings labelled Granite, Schist and Quarts.  Andrea says she wanted to make honest wines  that represented where they came from  but with a common thread of quality through them all.

In an effort to raise the profile of the area they teamed up Adi Badenhorst, Callie Louw and Eben Sadie as members of The Swartland Independent Producers and started the Swartland Revolution.

Q. Where were you born ?

Chris,” Cape Town in September 1976. Andrea, New Orleans in May 1978.”

Q. Where did you study ?  

Chris : “At University of Stellenbosch where I first did a B. Comm then a B.Sc Agric (Viticulture and Oenology). Andrea : University of California, Davis, Viticulture and Oenology.”

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

“There are so many different winemaking approaches , so while we have a specific  approach, it is not unique in the world. Our approach  is to try as best  as possible  to bottle wines that have a sense of place. So, we try to interfere as little as possible in the vineyards and in the cellar, but we are both  scientifically trained in Viticulture and Oenology, and will intervene if there is a potential  issue and we feel we absolutely have to. “

Q. How involved do you get in the Vineyard ?

“WE work with Rosa Kruger, and she manages all our vineyards. Chris and Rosa  have an understanding on how we want our vineyards farmed. We follow a “reasoned” approach, where for instance  we prefer to use cover crops , mulch and compost rather than herbicides and fertilizers. Chris regularly , in fact every week,  spends time in the vineyards with Rosa to ensure this is the way things are being done.”

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

“Our focus is on varieties that are suited to the sites they are planted in. So, in the Swartland, for Mullineux we work with Syrah, Grenache, Cinsault, etc. and for our Leeu Passant winery we work with Cinsault in Franschoek and in Stellenbosch we work with Cabernet Sauvignon, Cabernet Franc and Chardonnay.”

Q. Have you been influenced by any particular winemaker ?

Chris : “David Trafford and Eben Sadie played a strong influence  on me as a student. Their approach of trying to interfere as little as possible really resonated  with me at a time, late 90’s, when most of quality South African wine was made with a lot of intervention, extraction and new oak. After spending some time with David and then Eben in the cellar, I chose to seek out other producers around the world who were following a similar approach of trying to let wines show a sense of place and learn from them.”

Q. What would you consider your greatest achievement as winemakers ?

In unison “Helping to change the perception of the Swartland  Wine Region. Previously it was known for Bulk Wine, but together with the group of other producers we were able to change this in a relatively short time by focusing on quality, transparent winemaking, and preaching the same message when it comes to what the Region  does best.”

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

Together “There are no secrets !  Just a lot of hard work and no compromises.”

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

“Due to the warm dry climate, harvest is very quick and intense  in the Swartland. We do not have a fancy cellar, and we only use modern equipment where it is gentle on the fruit and can make our  lives easier in the cellar so we can keep fresh, focused and have time  to make  clear decisions on picking etc. Some modern equipment allows us to push  the boundaries  in the cellar a bit more  by allowing  us to  pick grapes “earlier”. Better hygiene allows us to use less sulphur, not to inoculate with yeast, etc. , and this helps our wines have a sense of place.”

To sum up : “After meeting we worked together for a few years , which proved we could work well together and only then got married ! We started our own winery in the Swartland, Mullineux, in 2007 and then in 2013  we partnered  with Anjit Singh. He had purchased a winery in Franschoek and we now make our Leeu Passant wines there and the Mullineux wines in the Swartland.

Almost as if by an afterthought they add “We were the Platter Winery of the Year in2014 and 2016 and Andrea was recognised by the USA Wine Enthusiast Magazine as their Winemaker of the Year in 2016.”

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Nutritional Wine Labels: The New Best Way to Lose Weight

A couple of months ago I started following a strict eating plan in order to shed some extra kilos. This plan, however, requires me to keep track of my daily calorie intake and output as to stay under a specific amount of net calories per day. This is all fine and dandy as the app that I am using can scan barcodes which makes the process of keeping track quite easy. But it wasn’t long before I found myself with quite the predicament- I can’t accurately count the calories in my glass of wine. And being the wine lover that I am, this is a serious problem. Yes, they do have generic examples of how many calories there would be in a glass of dry red wine (it can be anywhere between 110 and 200 calories), but being the scientist that I am, a guesstimate is not quite going to cut it. And why on earth in this day and age do wine and other alcoholic beverage labels not have nutritional information on them yet? It seems that everything else has them. An investigation is required!

So it turns out that in Europe and specifically in the UK, they are making some progress to include nutritional information such as calories on wine labels. Popular supermarkets in Britain are already including this information on their own bottled wines. Although the inclusion of nutrient information is not enforced by the European Union yet, it seems they want to encourage wineries and producers to come up with their own solution to the problem before penning down a new policy.

This is all very good news for a calorie counter such as myself, but I still can’t help to wonder why the wine industry is so hesitant to make this information available to the public. Do we not deserve to know what we are putting into our bodies? I don’t think this is the primary concern of the industry. I can only speculate, but the inclusion of nutritional information might seem like a counter intuitive action because it might lead to a decrease in wine sales. The thought is probably that consumers will drink less wine if they are aware of how many calories it contains. In the industry’s defence, I would say that is a fair assumption to make and there will be people that will think twice before finishing a bottle on their own after they have had a look at what is in it.  But isn’t that also an issue that is important to the industry? Promoting responsible drinking? Perhaps it is a good thing if that label stops someone that still has to drive home after the party from opening a second bottle.

Whatever the case may be, I personally look forward to the day when nutritional information is going to be included on wine labels, because let’s be honest it is inevitable. Until then, I will keep enjoying my glass(es) of wine- in moderation, of course- as it is still a better option calorie-wise than most other alcoholic beverages like beer, ciders and your favourite (I truly hope not) brandy & coke.

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Minimizing Spoilage of Wines in Barrel

By: Denise M. Gardner

The use of oak in the winery offers many options from winemakers.  With today’s availability of various oak products (i.e., chips, staves, powders), winemakers have more choices than ever before to integrate a wood component into their product.  However, the use of oak barrels remains an intrinsic part of most winery operations.  During the aging process, oak barrels have the potential to:

  • integrate new aromas and flavors into the wine.
  • add mouthfeel and/or aromatic complexity to the wine.
  • change the wine’s style.
  • add options and variation for future wine blends.

Additionally, the barrel room is often romantically viewed upon by consumers, and it is not uncommon for visitors to find barrel show cases in many tasting rooms, private tasting rooms, or while on a guided winery tour.

The barrel room at Barboursville Vineyards (VA) gorgeously catches the eyes of their visitors. Photo by: Denise M. Gardner

 

Oak fermenters at Robert Mondavi Winery (CA) that guests can see on their famous guided tour. Photo by: Denise M. Gardner

Nonetheless, barrels also offer challenges to wineries.  One of the most inherent challenges associated with a barrel program is maintaining a sanitation program.

The growth of spoilage yeast, Brettanomyces, is often discussed amongst wineries that utilize barrel aging programs.  However, additional spoilage yeast species such as Candida and Pichia have also been associated as potential contaminants in the interior of wine barrels (Guzzon et al. 2011).  Brettanomyces, commonly abbreviated as Brett, was first isolated from the vineyard in 2006 (Renouf and Lonvaud-Funel 2007) and until that point had most commonly been associated with the use of oak in the winery.  The growth of Brett in wine has the potential to impart several aromas as a result of volatile phenol [especially 4-ethylphenol (4-EP) and 4-ethylguaiacol (4EG)] formation in the wine.  Descriptors used to describe a Bretty wine include: barnyard, horse, leather, tobacco, tar, medicinal, Band-Aid, wet dog, and smoky, amongst others.  It should be noted that the presence of these aromas does not necessarily confirm that Brett is in the wine; there are other microflora, situations (e.g., smoke taint) or oak chars that can impart some of these aromas, as well.

Brettanomyces aroma descriptors. Image by: Denise M. Gardner

When barrels are filled with wine, it’s important to monitor the wine regularly for off-flavors while it is aging.  Wines should be regularly topped up with fresh wine to avoid surface yeast or acetic acid bacteria growth that can contribute to the volatile acidity (VA).  We usually recommend topping barrels up every-other-month.  Keep in mind that free sulfur dioxide concentrations can drop quicker in a barrel compared to a tank or wine bottle (MoreFlavor 2012) and free sulfur dioxide contractions should be checked (in conjunction with the wine’s pH) and altered as necessary to avoid spoilage.  Finally, when using a wine thief, both the internal and external part of the thief need cleaned and sanitized in between its use for each and every barrel to avoid cross contamination.  Dunking and filling the thief in a small bucket filled with cold acidulated water and potassium metabisulfite (acidulated sulfur dioxide solution) is a helpful quick-rinse sanitizer.

Barrels offer a perfect environment for microflora to flourish.  Wine barrels are produced from a natural substance (wood), which has its own inherent microflora from the point of production; obviously, barrels are not a sterile environment when purchased.  However, the structure of wood is rigid and porous, which provides nooks and crevices for yeast and bacteria to harbor within.  The porosity of the wood also makes it difficult to clean and sanitize, especially when compared to cleaning and sanitation recommendations associated with other equipment like stainless steel tanks.  Guzzon et al. (2011) found that barrels used over 3 years in production had a 1-log higher yeast concentration rate retained in the barrel compared to new and unused oak barrels.  This demonstrates the ideal environment within the barrel for retaining microflora over time, even when adequate cleaning and sanitation procedures are utilized in the cellar.

Common barrel sanitizers include ozone (both gas and aqueous), steam, hot water, acidulated sulfur dioxide, and peroxyacetic acid (PAA).  A study conducted by Cornell University on wine barrels used in California wineries found the use of sulfur discs, PAA at a 200 mg/L concentration, steam (5 and 10 minute treatments) to be effective sanitation treatments for wine barrels (Lourdes Alejandra Aguilar Solis et al. 2013).  In this same study (Lourdes Alejandra Aguilar Solis et al. 2013) ozone (1 mg/L at a 5 and 10 minute treatment) was also evaluated and found effective in most barrels tested, but a few barrels that did not show adequate reduction with the ozone treatment.  While the research conducted by Cornell indicated the potential lack of cleaning the barrel thoroughly before the ozone sanitation treatment, Guzzon et al. (2011) cited ozone’s efficacy is most likely caused by its concentration.  Both are important considerations for wineries.

Barrels should always be effectively cleaned of any debris and or tartrate build up before applying a sanitation agent.  This is essential to allow for maximum efficacy during the sanitation step.  High pressure washers, a barrel cleaning nozzle, and the use of steam are some options available to wineries in terms of physically cleaning the interior of barrel.  Additionally, some wineries use sodium carbonate (soda ash) to clean some of the debris (Knox Barrels 2016, MoreFlavor 2012) in addition to the use of a high pressure wash.  Always remember to neutralize the sodium carbonate with an acidulate sulfur dioxide rinse prior to filling with wine.

Dr. Molly Kelly from Virginia Tech University has previously recommended a 3-cycle repeat of a high-pressure cold water rinse, followed by high pressure steam before re-filling a used barrel and assuming the wine that came out of that barrel was not contaminated with spoilage off-flavors (Kelly 2013).  If the barrel is hot by the end of this cycle, it may be advantageous to rinse with a cold, acidulated sulfur dioxide solution before filling the barrel with new wine.  If there isn’t wine available to refill the barrel, it can be stored wet with an acidulated sulfur dioxide solution or using sulfur discs (Kelly 2013).

It is not usually recommended to store used barrels dry for long periods of time, and wineries can use an acidulated sulfur dioxide solution (top off as if it had wine in it) for long-term storage.  However, wineries that store their barrels dry need to rehydrate the barrels prior to filling with wine.  Check the cooperage for leaks, air bubbles, and a good vacuum seal on the bung.  Steam or clean water (hot or cold, overnight) are adequate rehydrating agents (Pambianchi 2002).  Barrels that leak wine offer harboring sites for potential yeast, bacteria, and mold growth, which can all act as contaminants to the wine itself.

It should be noted that contaminated barrels (barrels that produce a wine with off-flavors) may need extra cleaning and sanitation steps to avoid future contamination when the barrel is refilled.  It is typically recommended to discard barrels that have a recorded Brett contamination.  If the barrel has picked up any other off-flavors, especially during storage, it should probably be discarded from future wine fillings.

Barrels undoubtedly offer several challenges for wineries, including proper maintenance, cleaning and sanitation.  Nonetheless, engaging in good standard operating procedures for maintaining the barrel’s cleanliness can help enhance the longevity of the barrel and minimize risk of spoilage for several wine vintages.

 

References

Guzzon, R., G. Widmann, M. Malacarne, T. Nardin, G. Nicolini, and R. Larcher. 2011. Survey of the yeast population inside wine barrels and the effects of certain techniques in preventing microbiological spoilage. Eur. Food Res. Technol. 233:285-291.

Kelly, M. 2013. Winery Sanitation. Presentation at Craft Beverages Unlimited, 2013.

Knox Barrels. 2016. Barrel Maintenance.

de Lourdes Alejandra Aguilar Solis, M., C. Gerling, and R. Worobo. 2013. Sanitation of Wine Cooperage using Five Different Treatment Methods: an In Vivo Study. Appellation Cornell. Vol. 3.

MoreFlavor. 2012. Oak Barrel Care Guide.

Pambianchi, D. 2002. Barrel Care: Techniques. WineMaker Magazine. Feb/Mar 2002 edition.

Renouf, V. and A. Lonvaud-Funnel. 2007. Development of an enrichment medium to detect Dekkera/Brettanomyces bruxellensis, a spoilage wine yeast, on the surface of grape berries. Microbiol. Res. 162(2): 154-167.

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