By: Denise M. Gardner
As the growing season turns into full swing, now is the time to get things tidied up in the winery and prepare for this vintage’s harvest season. The cellar offers the advantage of being relatively cool in the summer months, so it offers an oasis away from the beating sun or those rainy, humid days. Managing some time for the up-and-coming harvest is a good way to keep cellar work current. Otherwise, the summer months can appear rather dull in the cellar. Here’s a list of considerations for the cellar crew:
Give your wines a regular analytical check
For anything that is sitting or aging in the cellar, now is a good time to schedule quality control monitoring. Wines in barrel need regularly topped off (every other month or every other 2 months) and checked for free sulfur dioxide concentrations if they have completed malolactic fermentation (MLF).
There’s a lot of good information out there on sulfur dioxide. If you feel slightly uncomfortable with sulfur dioxide additions or analysis, please refer to these current informational pieces that can be a valuable resource to any winemaker:
Wines that are getting ready to be bottled should go through a full analytical screen and recorded into the lab record books. This will provide insight for the winemaker in terms of how the wine should progress or need altered prior to bottling:
- titratrable acidity (TA)
- residual sugar
- residual malic acid concentration and malolactic fermentation completion
- free and total sulfur dioxide
- cold stability
- protein (heat) stability
- volatile acidity (VA)
AO apparatus set up to measure free sulfur dioxide. Photo by: Denise M. Gardner, Penn State Extension Enologist
For more information pertaining to how to set up wine analysis in your winery, please refer to Penn State Extension’s website on “Starting a Lab in a Small Commercial Winery.” Information on how to utilize analytical testing labs to the advantage of the winery can be found on the Penn State Extension website, “Wine Analytical Labs.”
For those wineries that have not previously measured cold stability, read Virginia Mitchell’s report on “Cold Stability Options for Wineries,” which explains the importance of testing and how to best treat your wines.
For more information on wine stabilization (sulfur dioxide additions, cold and heat stabilization), please refer to our previous blog post on “Stabilizing Wines in the Cellar.”
Get wines ready for blending or finishing
Now is a good time to pull samples of those wines that you are planning on bottling prior to harvest. After getting a good analytical evaluation, make sure you check the wines for their sensory perception. Is the wine at the caliber of quality that you were expecting? If no, what can you do to fix the wine and get it ready for bottling? Utilize fining agents or product additions to tweak the wines and enhance the quality.
Also consider blending. Blending can be a tool to help mitigate problem wines. But blending can also help you create a spectacular wine out of several great varietals.
Always remember to prepare bench trials before making changes to the entire tank or barrel of wine. Make sure that several people evaluate the wine and give you their individual evaluation. Have people write down their perceptions, as opposed to talking in a group, to avoid the power of persuasion and to minimize tasting insecurities. This practice will give you a more honest, objective evaluation of the wine.
Prepare for Bottling
The summer months are the ideal time to get your wines bottled and ready for release. Most wines need at least 2 to 6 months of bottle conditioning (i.e., time in the bottle before sale) to stabilize and minimize the effects of bottle shock.
Bottling is a time intensive process and requires a bit of planning by the cellar crew. Prepare a calendar for bottling days to ensure that all supplies are received for bottling, that wines are fully ready to be bottled, and that there is adequate time to get everything bottled prior to the estimated start date of harvest. For information pertaining to bottling considerations – how best to sanitize and monitor sterile filtration integrity – please refer to our previous blog post titled, “Bottling Tips and Considerations.”
Now is a good time to go through all of the supplies that are currently available in the winery and record how much you have of each. Recording inventory each year is a good way to evaluate what supplies are being purchased, what is being used, and what supplies are typically left over. It is possible for wineries to find some redundancies through this exercise and identify places to save money.
Suppliers’ “Free Shipping in July” promotions are just a month away! So being prepared with an accurate inventory can release some stress from the winemaker when it comes to ordering this season’s harvest supplies. Things to consider include:
- Yeast and Malolactic Bacteria
- Yeast Nutrients
- Any Enological Agents (e.g., Enzymes, Tannins, Polysaccharides/Inactivated Yeasts)
- Fining Agents
- Sugar and Acid
- Potassium Metabisulfite
- Cleaning and Sanitizing Agents
Make sure that all of the materials currently stored in the winery are being stored properly (i.e., dry chemicals away from wet chemical storage, food grade away from non-food grade, and the requirement that some may need stored frozen), according to the supplier’s recommendations, and that their expiration date has not expired. For some expired products, some suppliers may be evaluating their efficacy of the product past the expiration date. If you contact the supplier, you may be able to find an extended expiration date so that the product can be retained. Otherwise, expired products should be thrown out and re-ordered.
Additionally, going through an equipment inventory can be advantageous. Make sure all processing equipment is getting prepared to get a good cleaning and sanitizing regimen prior to the start of harvest. Unused equipment should not be a storage vessel for left-over, dirty rice hulls or mouse droppings. Use the summer months to check all of the equipment and make sure it is functioning properly. If there are problems with equipment, it is best to identify it over the summer and, hopefully, get serviced before the start of harvest. Don’t forget to check tank valves, pumps, inspect hoses for cleanliness, and all of the processing equipment. Using an inventory, or check sheet, is a good way to ensure equipment is up to par is a good way to keep track of everything’s condition. Also, evaluating barrel needs and tank space available for harvest can be added to the inventory sheet.
If you have a wine lab, now is also a good time to check the chemical and supply inventory in the lab. Remember – free shipping in July is just around the corner! Document expiration dates of chemicals and make a list of new chemicals, analytical standards, or equipment (e.g., hydrometers, pipettes, pipette bulbs, sampling bottles, etc.) that should be purchased prior to harvest.
Inventory all of your supplies to get prepared and organized for the upcoming harvest. Photo by: Denise M. Gardner, PSU Extension Enologist
Take time to evaluate and write SOP’s
Standard Operating Procedures, SOP’s, can help minimize the chaos during harvest. Having up-to-date SOP’s in the cellar and lab will help minimize the number of times people will always have to ask “the boss” for help.
If you don’t have SOP’s, consider starting small and documenting protocols for things like lab analysis. Plenty of resources (e.g., websites, text books) are available and can be used to create a standard protocol that works for your winery.
After tackling lab analysis, consider writing an SOP for harvest operations. Think about writing an SOP for each piece of equipment that your harvest team will need trained on. Take the crusher/destemmer for example:
- How is the crusher/destemmer hooked up?
- How to prepare the crusher/destemmer for fruit arrival (include cleaning and sanitizing procedures).
- Do you have validation measures to ensure that the equipment is properly cleaned (a visual evaluation? Some sort of analytical testing?)?
- Do you have a record system that documents the equipment has been properly prepared, cleaned, and sanitized? If so, where is that documentation and how does your staff document this step?
- What is the protocol for running the crusher/destemmer? What safety features should all employees be trained on? Document all safety procedures.
- How is the crusher/destemmer cleaned and sanitized after each lot (varietal) of fruit that is run through the equipment?
- How is the crusher/destemmer cleaned and sanitized after each processing day? Where is the equipment stored and how is stored?
Winemakers can also document processing decisions. For example, if you know that you are going to process Vidal Blanc every year, consider writing an SOP specific for how the Vidal Blanc is processed. Write out each step, the quality control checks (i.e., checking fruit chemistry or monitoring fermentation) and what processing aids are typically added to the Vidal (e.g., yeast, enzymes, etc.).
Winemakers should also have an SOP ready for when fruit arrives to the winery in less than ideal conditions. For information on what winemakers should consider, please read the two articles on Penn State Extension’s website titled “Producing Wine with Suboptimal Fruit.”
Botrytis disease pressure on Pinot Grigio grapes. Photo by: Denise M. Gardner
Having a fully functional and trained cellar crew is a good foot forward as the harvest months approach. While preparation is tedious, it can save some time and resources during the busy harvest season… and hopefully, minimize the chaos!
We are all well aware of the recent worldwide culinary explosion and the resulting snowball effect it has had on food and wine pairings. In our little Stellenbosch district alone you can now not only attend wine pairings with the usual suspects like cheese, chocolate, olives or biltong, but with new – and sometimes slightly strange – pairings with meringues, pizza, cupcakes and ice cream (?!) So I sat down for a while to try and understand what the hype is all about.
Before beginning, I should probably mention that I consider myself to be quite the foodie. And as I find myself working in the wine industry, I couldn’t help but marry these two great passions of mine. It all started the first time I used wine in my food while preparing some spaghetti bolognaise. That is when I realized that wine is not always just for drinking on its own or pairing with an array of food items, but it can be used to literally fuse the two into something spectacular. The addition of wine to a dish just brings flavours together in a way that not many other ingredients can.
The fusion of food and wine can of course also be observed from a scientific point of view. The internet and countless books are overloaded with charts and diagrams explaining what to pair with what and why exactly Riesling pairs well with rosemary etc. Some say it all comes down to the molecules and the pairing of similar flavour compounds, others believe it is about mouth feel or the balancing of astringency with fattiness. For the home cook and casual wine drinker all these terms and concepts might seem a bit daunting or even far-fetched, but there are some interesting and easy to apply flavour combinations out there. Just remember that pairing your favourite wine with offal is not going to help you to suddenly like it more, no matter what the science says about the similar aromatic compounds.
Personally, I think food and wine go together so well, because they both have an unique way of bringing people together. The incredible success of food & wine festivals are surely a testament to that. There is something nostalgic about sitting down with family and friends around a great big table filled with all the gloriously glazed food you can think of, and uncorking a bottle of your favourite vino, filling everyone’s glasses and being merry. And it’s no surprise as this is certainly not a new concept- the accompaniment of wine with food has come along since, possibly, the dawn of time and there is absolutely no sign that the tradition will fade away any time soon. We drink red wine and eat chocolates or ice cream out of the tub in front of the TV when we’re sad; we drink wine (or MCC) and eat canapés when we are celebrating a special event- and we hardly ever do these things on our own. There is always that best friend that will cry (and drink) with you, and be it your colleagues or closest friends, they will share in your joy and raise a toast to your accomplishments.
People of all shapes and sizes and different cultural backgrounds are excited by food and a good bottle of wine and enjoying it with great company makes the experience just that much more memorable. And as I always say, having wine with your food makes it a meal.
Q. Where do you originate ?
“I am another non-Kaapenaar. I was born in Kempton Park, Gauteng.”
Q. Where did you study ?
“I am a product of the University of Stellenbosch where I did a BSc. Agric Oenology and graduated in 2007.”
Q. What made you interested in wine ?
“I came to Stellenbosch to study Bio-organic chemistry to get into Forensics but then made a friend who was doing viticulture. One day I went to a practical with her and fell in love with the vineyards. That made me change my degree.”
Q. How did you come to be at Perdeberg ?
“Perdeberg has experienced considerable growth and have a new barrel cellar and needed someone to assist cellar Master Albertus Louw. I was lucky to be appointed to that new post in 2015.”
Q. What did you do before Perdeberg ?
“ While still at University I worked in the experimental cellar then I worked at Avontuur Estate near Stellenbosh for a few years then moved to Allee Bleue Wines at entrance to Franschhoek .”
Q. Do you consider your winemaking to differ to others ?
“I think winemaking is a bit like cooking, while it is good to follow recipe, sometimes you must be guided by your taste buds and your mood. I try not to overthink the wine….I try and let the wine speak to me and from there I will fine tune things.”
Q. How involved do you get in the vineyard ?
“At the moment, at Perdeberg, not much. Our viticulturist , Heinie Nel and Production manager, Albertus Louw look after the vineyards.”
Q. Do you have any varieties you prefer to work with ?
“I have an affair with Pinot noir and Cabernet franc ! I love the finesse you can get in Pinot noir and I think you either get it right or not ! It can be diverse, depending on the area it is planted in. I prefer the more fruity style, but have had some lovely earthy styles. Cabernet franc is such an interesting variety and prefer the Helderberg area., mainly because you get that greater greener style. I had success with these varieties at Avontuur in 2008 and 2009.”
Q. Have you been influenced by any particular winemaker or by a wine region ?
“As yet I have not travelled overseas but each area I have worked in the Cape has taught me just how important origin is.”
Q. What do you consider your greatest achievement as a winemaker ?
“It is early days yet but my first four star wine was a great moment. It was a Shiraz I made at Avontuur. This wine was to become part of their premier range, named after their first stallion, Dominion Royale. It took a lot of tasting and selection with many potential blends. After some five months I was pretty sure of two combinations and a good idea which would be best. It was confirmed by the GM and bottled as the 2008 which was a very hot year with high alcohols. It is a big robust wine with a mixture of white pepper, and black fruits with 15 % alcohol. It is developing beautifully.”
Q What “secrets” have you “developed” that make your wines different to others ?
“I don’t have any secrets but as mentioned I treat each wine on it’s own and listen to the wine.”
Q. How important is modern winemaking equipment in your winemaking ?
“It makes life a lot easier especially when working in big volumes.” Then adds, after a bit of thought “As long as things are working properly !”
Q. What do you think the heat of 2016 will “do” to the vintage ?
“It will keep me on my toes, for sure. It will be another interesting year for reds. Very concentrated flavours.”
Q. What do you prefer to drink when relaxing ?
“In summer I love dry rose. Some would say I am in my “Rose phase” ! I enjoy fresh Sauvignon Blanc or a slightly chilled Pinot Noir. In winter our Cape red blends or Shiraz. I n very good company I will take out my special Cabernet Franc.”
The long months post-harvest require regular attention by cellar staff and winemakers to ensure that wine quality is upheld through storage conditions. Wine stability, while somewhat nebulous, is essential to obtain in order to ensure the wine’s quality will be upheld post-sale. Below is a list of cellar maintenance practices that are recommended in preparation before the growing (and bottling) season.
Monitor Sulfur Dioxide Concentrations
Now (i.e., the winter and spring months) is a good time to regularly check sulfur dioxide concentrations of wines sitting in tanks and barrels waiting to get bottled. At minimum, wines should be checked once a month for free sulfur dioxide concentrations. Some winemakers opt to check barreled wines every other month in order to minimize frequently opening the barrel.
Proper sanitation and sampling is required for best analytical results:
- Use clean sampling bottles when taking wine samples
- Make sure that you sanitize any valves or sampling ports before and after releasing a sample from a tank. At the very least, you can use a food-grade alcohol solution spray or a citric acid-sulfur dioxide mix as a sanitizing agent.
- Properly clean and sanitize wine thieves or other sampling devices each time you use it to take a sample from a barrel or the top of tank. Warm water is not enough to sanitize a wine thief. We recommend using a citric acid-sulfur dioxide mix for quick dipping in between barrel sampling.
For wines that have completed primary fermentation and/or malolactic fermentation, maintaining a molecular free sulfur dioxide concentration is helpful to reduce the risk of yeast and bacterial spoilage. For a review on sulfur dioxide and making sulfur dioxide additions, please refer to this Penn State Wine Made Easy fact sheet.
It is essential to clean and sanitize your wine thief in between sampling from barrels. Photo from: Denise M. Gardner
Cold (Tartrate) Stabilization
Cold stabilization is often utilized to avoid the precipitation of tartrate crystals, which is common in instable wines at cooler temperatures.
In 2012, Virginia (Smith) Mitchell, now head winemaker at Galer Estate Winery, wrote a primer on cold stabilization techniques available for wine producers: http://extension.psu.edu/food/enology/analytical-services/assessment-of-cold-stabilization This primer covered everything from how to analyze for cold stability to the use of carboxymethylcellulose (CMC) to avoid tartaric acid crystallization in wine.
Prior to putting a wine through cold stabilization, it is worth the time and effort to analyze the wine for cold stability. Not all wines end up having cold stabilization problems. For those wines that do not, going through the cold stabilization process can actually minimize wine quality by stripping out delicate aromas and flavors, or altering taste or mouthfeel attributes of the wine. This doesn’t touch upon the amount of wasted time and effort to cold stabilize wines that are otherwise cold stable.
The above report recommends several testing procedures to ensure tartrate stability of a wine.
With the relatively warmer 2015-2016 winter, many winemakers may need to turn to artificial chilling in order to cold stabilize their wines properly. Again, this could be used as an argument to test wines prior to cold stabilization to minimize the use of electricity and to better manage the flow of wines in and out of the cold stabilization tank.
Wines that do undergo cold stabilization will likely have changes in pH and titratable acidity (TA) that can ultimately affect other parameters of the wine: protein (heat) stability, color, sulfur dioxide concentrations, and volatile acidity. It is prudent to check these components analytically following the cold stabilization process.
Protein (Heat) Stabilization
Proteins in wine can elicit hazes in wines post-bottling that may be off-putting to some consumers. While the proteins cause no effect on wine quality, they do cause an alteration in the appearance of the wine. Some varieties, like Gruner Veltliner, have naturally high concentrations of proteins, and, therefore, require a more aggressive approach to protein fining. Other varietals, however, may not require protein fining with bentonite at all.
Wines should undergo protein (heat) stability after they are cold stabilized due to the fact that cold stabilization will affect the acidity (pH and TA) of the wine, and therefore, alter protein stability properties of the wine. Again, winemakers are encouraged to check the wine for protein stability prior to treating a wine with bentonite.
Bentonite is a fining agent used to bind any proteins in a wine that would otherwise be considered unstable. However, if the addition of bentonite is unnecessary (i.e., the wine is protein stable and does not provide a component for bentonite to bind to, bentonite can bind to other components in the wine, most specifically: aroma and flavor active compounds. While this has been shown in the research literature, it is unclear how detrimental the loss of aromatic compounds is to the wine (Marchal and Waters 2010). Additionally, bentonite additions have been noted to strip color out of rosé and red wines (Butzke 2010).
A summary from UC Davis on heat stability testing can useful to understand the positive points and limitations of protein stability testing. Protocols for heat stability tests can be found here from Dr. Bruce Zoecklein. Additionally,ETS Labs has provided a small summary of how to interpret heat stability results, which can be helpful for wineries that are not used to reading analytical results on this test.
Additionally, wineries can submit wines to ISO-accredited labs for a bentonite trial in which the lab pinpoints the exact concentration of bentonite needed to heat stabilize the wine. This may be helpful to avoid making too little or too much bentonite additions, which costs time and labor in the winery.
Bench trials may be needed to determine how much bentonite is needed to obtain protein stability of your wine. Remember to use the same source and lot of bentonite in both your bench trials and commercial application. Photo from: Denise M. Gardner
Finally, if wineries are conducting their own bench trials, they are encouraged to use the same lot of bentonite in both the trials and the commercial application (Marchal and Waters 2010). This is due to the natural variability associated with most bentonite products. Finally, unless otherwise stated by the supplier, bentonite should always be blended in chlorine-free, hot (60°C, 140°F) water (Butzke 2010), and allowed to cool to room temperature so that the bentonite can swell. Allowing the slurry to cool will ensure that the wine is not exposed to a hot slurry.
Butzke, C. 2010. “What Should I use: sodium or calcium bentonite?” In: Winemaking Problems Solved. Christian E. Butzke, Ed. Woodhead Publishing Limited and CRC Press, Boca Raton, FL. ISBN: 978-1-4398-3416-9
Marchal, R. and Waters, E.J. 2010. “New directions in stabilization, clarification and fining of white wines.” In: Managing wine quality, volume 2. Andrew G. Reynolds, Ed. Woodhead Publishing Limited, Great Abington, UK. ISBN: 978-1-84569-798-3
Iland, P., N. Bruer, A. Ewart, A. Markids, and J. Sitters. 2012. Monitoring the winemaking process from grapes to wine: techniques and concepts, 2ndedition. Patrick Iland Wine Promotions Pty. Ltd., Adelaide, Australia. ISBN: 978-0-9581605-6-8.
Penn State Extension Wine Made Easy: Sulfur Dioxide Management:http://extension.psu.edu/publications/ee0093
Penn State Extension: Assessment on Cold Stabilization:http://extension.psu.edu/food/enology/analytical-services/assessment-of-cold-stabilization
UC Davis: Heat Stability Testing:http://wineserver.ucdavis.edu/pdf/attachment/88%20stability%20tests%20and%20haze%20formation%20.pdf
Virginia Tech: Protein Stability Determination in Juice and Wine (1991):http://www.apps.fst.vt.edu/extension/enology/downloads/ProteinS.pdf
ETS Labs: Interpreting Heat Stability Tests:https://www.etslabs.com/assets/PTB011-Interpretation%20of%20Heat%20Stability%20Results%20and%20Turbidity%20Readings.pdf