By: Denise M. Gardner, Enology Extension Associate
Most likely, all of the wines from the 2016 vintage are happily settling away in tank or barrel at this point. After such a busy time, his leaves winemakers with that tricky question, “What do I do now?”
Monitoring Malolactic Fermentation (MLF)
Now is a good time to make sure you are monitoring your malolactic fermentations. Ensure all of your barrels or tanks have been appropriately inoculated, or have started naturally, and get some initial readings on the malic acid concentration.
If you have a spectrophotometer, you can purchase enzymatic kits to measure the concentration of malic acid in your wine over time. Wines with less than 30 mg/100 mL of malic acid are considered “dry” for MLF or MLF-stable for bottling.
However, winemakers can also monitor malic acid degradation through the use of paper chromatography kits. These kits are easy enough for home winemakers to use and can also be applied at the commercial level.
Paper chromatography works by separating tartaric, malic, and lactic acids from a wine sample (Figure 1). In addition to blotting small drops of your various wine samples, each paper must also contain 3 standards to show the spots documented by the three acids (tartaric, malic, and lactic). While paper chromatography is not the best at concentrating how much of each acid remains in the wine, you can get an idea when the bulk of malic acid is converted to lactic acid (i.e., MLF is completed) when the malic acid spot associated with the wine samples disappears.
For a complete protocol on paper chromatography, please see this page: https://www.midwestsupplies.com/media/downloads/421/malolactic_chromatography_kit.pdf
Checking Wines for Off-Flavor Development
It’s also a good time to check wines for hydrogen sulfide (H2S) or sulfur-base off-odor aromas, and volatile acidity (VA), especially for wines that you will want to bottle early in the new year.
Hydrogen sulfide can be treated with copper sulfate. Penn State Extension offers a great 2-page fact sheet on how to run a copper screen to determine if the wine requires copper sulfate, and a copper bench trial in order for you to assess how much copper is needed to treat the hydrogen sulfide: http://extension.psu.edu/food/enology/wine-production/wine-made-easy-fact-sheets/sulfur-based-off-flavors-in-wine
Now is also a good time to know what the VA is in your wines, especially those that will be seeing some aging. This is incredibly important to get a baseline value of the VA. That way, if a problem emerges in the future, you will have an indication how much the volatile acidity has increased. Penn State Extension also offers a 2-page fact sheet explaining why knowing volatile acidity is important, provides protocols for its analysis, and how to mediate high VA situations: http://extension.psu.edu/food/enology/wine-production/wine-made-easy-fact-sheets/volatile-acidity-in-wine
If you are having problems identifying these key defects in your wine, don’t forget that the annual “Wine Quality Improvement” Short Course is just around the corner in January. For more information on this workshop and its registration, please go here: 2017 Wine Quality Improvement (WQI) Short Course
Now is also a good time to clean up any leftover sore spots from the chaotic harvest season:
- Clean up places in the cellar that have gotten dirty or have become areas that are accumulating materials that should otherwise be put away.
- Manage all of your harvest records. Make sure all of the wines have the basic wine chemistries (e.g., pH, TA, residual sugar, alcohol, free and total SO2, malic acid, and volatile acidity) in the record book. It is easy to forget all of these details as time progresses.
- Make sure wines are properly stabilized for storage. Treat wines appropriately with sulfur dioxide. If you need some tips on sulfur dioxide management, refer to Penn State Extension’s Wine Made Easy fact sheet: http://extension.psu.edu/food/enology/wine-production/wine-made-easy-fact-sheets/sulfur-dioxide-management
- If you know you need to move wines off of lees, now is a good time to go through each tank one-by-one and make the necessary adjustments.
How does delaying spur-pruning to the onset or after bud burst impact vine performance? Insights from recent studies
By Michela Centinari
Now that harvest is finally over and wines are tucked away in the cellar, it is time to prepare for the next year. One of the first concerns that many growers feel in a new growing season is that worry of spring frost and the associated potential risk of vine injury. In the spring of 2016, for example, an unusually warm March was followed by a very cold start to the month of April, which resulted in damaging frost incidences in some vineyards of the Mid-Atlantic region.
Susceptibility to frost injury increases with advanced phenological growth stage , therefore, growers and scientists have explored different techniques for delaying bud burst of grapevines to increase the chance of avoiding spring frost damaging events. Vegetable-based oils (e.g., Amigo oil) can be sprayed on the canes/buds during the winter to slow down bud de-acclimation and delay the resumption of vegetative growth in the spring [2; 3; study at Penn State]. Delaying pruning until late winter can also be used to delaying bud burst of vines growing in frost prone areas.
Canes of cordon-trained vines can be pruned to 2-3 node spurs late in the winter or even when apical buds begin to open to delay bud burst of basal buds. Due to the strong apical dominance of Vitis vinifera cultivars, apical buds of an unpruned cane tend to burst first, which inhibits development and growth of median and basal buds  (Figure 1).
What may happen if we wait until the onset of bud burst or even later to prune the vines?
Spur-pruning the vines when the apical buds of un-pruned canes are already open may not only delay bud burst of the basal nodes, but may also postpone other phenological growth stages such as bloom, fruit-set, or even veraison with potential consequences for vine yield and fruit chemical composition at harvest .
I recently read two articles on this topic published in the American Journal of Enology and Viticulture (Post-bud burst spur-pruning reduces yield and delays fruit sugar accumulation in Sangiovese in central Italy  ) and in Frontiers in Plant Sciences (Phenology, canopy aging and seasonal carbon balance as related to delayed winter pruning of Vitis vinifera L. cv. Sangiovese grapevines ).
The studies described in these articles aimed to assess if and how delaying winter spur-pruning of Sangiovese vines to the bud swelling stage or later, after bud burst, impacted the annual growth cycle of the vines and its productivity.
The studies were conducted in Italy and the researchers were specifically interested in assessing if vines pruned around or after bud burst exhibited a delay in grape ripening as compared to those pruned during the winter, resulting in lower sugar accumulation and higher acidity in the fruit at harvest. A steady trend of increased warming is, indeed, pushing some Mediterranean grape growing regions toward accelerated ripening , which could lead to excessive or overly fast sugar accumulation in the fruit, high alcohol in the wine, unacceptably low acidity, high pH, and also atypical grape flavors and aromas .
Although excessive or overly fast sugar accumulation may not be a problem in our region, it’s still important to understand if delaying winter pruning to extremes could be used to delay bud burst and reduce risk of frost damage, as well as the impact this practice may have on vine yield, and fruit and wine chemistry. This is a topic of further interest in light of changing climatic conditions and the potential increase of unpredictable weather patterns like early spring warming and late spring frosts .
Below, I will summarize the two previously mentioned studies emphasizing results which can be of interest to wine grape growers in our regions.
Both studies were conducted on mature Sangiovese (Vitis vinifera L.) vines. The first study was established in a commercial vineyard in central Italy, whereas the second study was conducted on vines growing outdoors in 10-gal pots at a research station in northern Italy. Groups of vines were assigned to different pruning treatments. Vines assigned to the standard grower practice treatment were spur-pruned to 2 basal nodes during the winter when buds were dormant. Vines assigned to the other treatments were spur-pruned at more unusual times from the bud swelling to full bloom (Figures 2 and 3A).Did delaying vine spur-pruning to after bud-burst consistently delay the whole annual growing cycle?
Basal buds of Sangiovese vines spur-pruned when apical shoots were about 1.6″ long (called late pruning treatment; Figure 3A central panel) burst 17 days later than those of vines pruned in the winter, when buds were dormant (called standard pruning treatment; Figure 3A left panel). Pruning the vines even later, when apical shoots were about 4.7-5.5″ long (called very-late pruning treatment; Figure 3A right panel) extended the delay in bud burst to 31 days as compared to vines pruned in the winter Unfortunately no phenology data were recorded for vines pruned at bud swelling stage (study 1).
The delay in phenological growth stage decreased over the season. For example, late-pruned and very-late pruned vines reached veraison 3 and 13 days, respectfully, after those pruned in the winter (Figure 3C). Shoots of vines pruned after bud burst developed later in the season under higher air temperature than those of vines pruned during the winter. Greater air temperature may have helped shoots of late- and very-late pruned vines to reach bloom and veraison in fewer days as compared to those pruned earlier .
By harvest the delay was fully off-set for the late-pruned vines: they reached the sugar level set for ripening (~ 19 ºBrix) three days before those pruned in the winter. Grapes of very-late pruned vines reached 19 ºBrix 6 days after those pruned in the winter.
Spur-pruning vines after bud burst significantly reduced crop yield compared to standard winter pruning
Vines pruned at bud swelling growth stage had similar crop weight, number of clusters per vine, and cluster weight than those pruned when buds were still dormant. Pruning vines after bud burst, however, reduced yield as compared those pruned during the dormant season. For example, late pruned vines (spur-pruned when apical shoots were about 1.6″ long; Figure 3A central panel) had 26% lower crop yield as compared to those of the standard pruning control group (spur-pruned before bud burst). Reduction of crop yield was related to lower cluster weight and lower number of berries per cluster. While there is not a clear explanation on why late-pruned vines had fewer berries per cluster, several hypotheses were presented including increased production of gibberellins during the initial flush of growth in the late-pruned vines .
Waiting even longer to prune the vines had a detrimental effect, reducing not only cluster weight but also the number of clusters per vine. For example, vines pruned to two basal nodes when the apical shoots were already flowering had no crop at harvest. When vines were pruned so late the basal shoots did not develop flowers and remained vegetative after pruning. I am not sure why any growers would want to wait until bloom to prune the vines, but it’s still interesting to see how such a drastic treatment may limit sources of carbohydrates for developing cluster primordia .
Although uncertainty still exists, the authors suggested that delaying spur-pruning until after bud burst, but not to extremes, may have the potential for reducing crop yield in high-yielding cultivars such as Sangiovese planted in specific regions of Italy. However, long-term field studies are necessary to assess if it is possible to calibrate winter pruning date for managing yield reductions and/or fruit maturation rate.
Did delaying vine spur-pruning to bud swelling stage or after bud burst consistently impact fruit chemistry?
The effect of the timing of spur-pruning on fruit composition at harvest varied between studies and with the extent of the pruning delay. For example, Sangiovese vines late pruned (apical shoots 1.6″ long) had higher total soluble solids (+ 1 °Brix), total anthocyanins and phenolics than winter-pruned vines. However, vines growing in a commercial vineyard (study 1) and spur-pruned to two basal nodes later in the season, when inflorescences of apical shoots were already swelling (Figure 3C), had lower sugar concentration (-1.6 °Brix) and higher TA (+1.8 g/L tartaric acid) than those pruned during the winter, but at the same time they also had higher anthocyanins and phenolic concentrations. This result suggests that spur-pruning canes after bud burst may decouple the accumulation patterns of total soluble solids and anthocyanins, phenolic metabolites. This could be intriguing for growers trying to delay fruit sugar accumulation and acid degradation, while maintaining wine color, but on the another hand it could also come with a reduction in crop yield, quantified to over 50% in this study .
Did delaying winter spur-pruning have negative carry-over effects on the following season?
Pruning vines at the bud swelling stage did not have negative effects on vine growth in the following year. It did not impact bud fertility (number of clusters per shoot) or winter carbohydrate storage, which is important for winter vine survival and following year resumption of growth. However, pruning the vines to two-nodes after bud burst, specifically when inflorescences of apical shoots were already swelling (Figure 3C), reduced bud fertility by 50% in the following year. Those vines were able to recover once standard winter pruning was applied again at the end of the study.
These studies conducted on Sangiovese vines grown in Italy found that:
- Winter spur-pruning can be applied up to bud swelling without adversely affecting vine yield, grape composition at harvest or bud fertility in the following year.
- Vines pruned after bud burst show pronounced delay in shoot development at the beginning of the season, which increased as the pruning time was further delayed. Under the warm conditions of these studies the delay in phenological growth stage decreased or even disappeared over the season. This could be partially explained by the fact that late-pruned vines needed less time than vines pruned during the winter to reach maximum photosynthesis efficiency.
- Delaying spur-pruning to after bud-burst may reduce vine yield, decrease sugar accumulation and bud fertility in the following year.
Delaying winter pruning of vines located in frost prone areas to the onset of bud burst or shortly after that may be used as frost avoidance technique. However, we need to further understand how a delay in shoot development and potentially a shorter growing season (number of days from bud burst to harvest) may impact fruit ripening, yield component, vine over-winter carbohydrate storages and susceptibility to winter cold temperatures, as well as the following year growth. The studies summarized here were conducted in a warm region with a growing season longer than many areas of Pennsylvania. Further research is necessary to corroborate those results under our regional climatic conditions.
- Centinari M, Smith MS, Londo JP. 2016. Assessment of Freeze Injury of Grapevine Green Tissues in Response to Cultivars and a Cryoprotectant Product. Hortscience 51: 1–5.
- Dami I, and Beam B. 2004. Response of grapevines to soybean oil application. J. Enol. Vitic. 55: 269–275.
- Loseke BJ, Read PE, and Blankenship EE. 2015. Preventing spring freeze injury on grapevines using multiple applications of Amigo Oil and naphthaleneacetic acid. Scientia Hort. 193: 294–300.
- Friend AP, and Trought MCT. 2007. Delayed winter spur-pruning in New Zealand can alter yield components of Merlot grapevines. J. Grape Wine Res. 13: 157–164.
- Frioni T, Tombesi S, Silvestroni O, Lanari V, Bellincontro A, Sabbatini P, Gatti M, Poni S, Palliotti A. 2016. Post-bud burst spur pruning reduces yield and delays fruit sugar accumulation in Sangiovese in central Italy. J. Enol. Vitic. 67:419–425.
- Gatti M, Pirez FJ, Chiari G, Tombesi S, Palliotti A, and Poni S. 2016. Phenology, canopy aging and seasonal carbon balance as related to delayed winter pruning of Vitis vinifera cv. Sangiovese grapevine. Frontiers in Plant Sciences 7:1–14. Article 659.
- Jones GV, White MA, Cooper OR, and Storchmann K. 2005. Climate change and global wine quality. Climatic Change 73: 319–343.
- Mosedale JR, Wilson RJ, and Maclean IMD. 2015. Climate change and crop exposure to adverse weather: Changes to frost risk and grapevine flowering conditions. PLoS One 10:e0141218.
- Lorentz DH, Eichorn KW, Bleiholder H, Klose R, Meier U, and Weber E.1995. Phenological growth stages of thegrapevine (Vitis vinifera ssp. vinifera). Codes and descriptions according to the extended BBCH scale. Aust. J. Grape Wine Res. 1, 100–103.
By: Kevin Martin, Penn State Extension Educator (Portland, NY)
We are starting to see increases in herbicide management costs. Some of you know all to well that 1-2 applications of herbicide do not provide adequate control of weed competition in vineyards. Complicated tank mixes that cost over $100 per applied acre are not a practice I would consider sustainable. Some growers, though, would disagree.
The cost of materials are not increasing substantially. More frequent applications and a need to apply better materials more often is driving costs up. The majority of herbicides used by growers are off patent these days and available almost exclusively in generic form. A third or even fourth vineyard pass, could be sustainable. The cost of materials and materials selected needs to be looked at comprehensively with the number of passes required to obtain adequate control.
There may be a potential for cover crops to improve the effectiveness of weed control. We can observe this not just in row middle management, but to a lesser extent under trellis management. Cover crops do not offer the potential to reduce herbicide applications in situations where growers are applying between 1 and 3 per year. Rather, they offer an option to improve results without adding an additional pass. This is because cover crops can reduce vine size when row middle competition is undesirable. In 2016 field trials we observed smaller berry size when cover crops were planted in the late summer of 2015 and were not terminated before June 1, 2016. Particularly where hard to control species get established, some growers have added a late summer or fall application to bring their total number of herbicide application to 4-5. In this scenario, the right cover crop mix offers the potential of superior control with one less pass. Cover crops do require some form of termination (usually chemical). By selecting the right species, a low rate of round-up may offer excellent row middle control.
Cover crop mixes being trialed are similar in cost to an herbicide application. Low-end rye grass and radish blends are comparable to many post emergent row middle applications. Higher end seed mixes with oats, more radishes or even buckwheat range between $12 and $15 per seeded acre in materials. Legumes increase costs but potentially reduce fertilizer use. Easy to kill hybrid crimson clover complicates the economic analysis. It may reduce urea applications by 50%, but could be more difficult to grow. Understanding effective seed mixes, their primary benefits and potential secondary benefits will be key to the success of moving cover crops into perennially systems in a cost-effective (saving) way. Regional differences in seed prices also complicated the matter. One of our primary suppliers of cover crop seeds in the Lake Erie Region is Ernst Seed Co. 2016 prices were used to calculate the cost of various seed mixes used in trials.
LERGP, led by Luke Haggerty, is taking an integrated look at cover crops in Concord vineyards. As he observes benefits, I’ll help quantify them. There is a lot we still do not know. While preliminary results show promise for increasing economic sustainability where herbicide program prices are spiraling upward, a few years’ worth of data will allow us to clearly observe measurable benefits in herbicide programs. Right now, it just seems like there are less weeds and more cover crop in row middles that have been seeded.
 Tang, Yijia, Miguel I. Gómez, Gerald B. White. COST OF ESTABLISHMENT AND PRODUCTION OF HYBRID GRAPES IN THE FINGER LAKES REGION OF NEW YORK, 2013. Cornell, Dec. 2014, http://publications.dyson.cornell.edu/outreach/extensionpdf/2014/Cornell-Dyson-eb1411.pdf Accessed 3 Nov. 2016.
 Bowman, Greg, Craig Cramer, and Christopher Shirley. Managing Cover Crops Profitability. 3rd ed.: Sustainable Agriculture Research and Education. SARE, July 2012, http://www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition Accessed 3 Nov. 2016. pp. 394.
 Id. At 122 – 124.
By: Denise M. Gardner
While in the midst of harvest (and all the craziness that comes with it), I thought I’d take a week to remind people about proper cleaning techniques, improving sanitation, and why these two operations are essential for wineries.
I know many of you are ready to close this page now, but WAIT!
I have heard many excuses for short cutting on cleaning over the years. Do any of the following sound familiar?
- There is not enough time in the day to properly sanitize.
- There are not enough employees to do all the work to properly clean.
- Cleaning would take all night to complete properly.
- It’s not necessary to clean/sanitize with wine.
- The wine will sell anyway.
- Cleaning and sanitizing does not actually improve wine quality.
- Sanitation is not really important.
- Proper cleaning does not increase the price in which the wine can be sold.
If you or any of your employees have used at least one of these statements in the past, you could be suffering from poor cleaning and sanitation practices!
In all seriousness, having good cleaning and sanitation procedures can actually save the winery time and money in the long run.
In the height of harvest, I’m sure this is a tough sell. But let’s consider some of these practical cleaning and sanitation suggestions for small, commercial wineries.
On the same page with cleaning vs. sanitizing
Let’s start with a review of definitions, as it can get very confusing. Below are some general definitions taken from a series of sources (Fugelsang and Edwards 2007, Iland et al. 2007, Iland et al. 2012, Solis et al. 2013) to explain the differences between cleaning, sanitation, and sterilization.
- Cleaning – the physical removal of dirt, debris or unwanted material (solid or liquid) from a surface
- Sanitizing – a 99.9% (3 log) reduction of microorganisms
- Sterilizing – the complete removal or inactivation of microorganisms
The wine industry is primarily focused on cleaning and sanitation protocols, as there are not many sterile practices utilized in winery operations (unless you are one of the lucky few wineries bottling aseptically). Even if processors are using sterile filtration to remove yeast and bacteria from the wine, once the wine exits the filter, it comes in contact with equipment that is only sanitized (hopefully!).
Additionally, wine bottles or packages are not sterile when being filled. Even new bottles can contain yeast or bacteria that can potentially contaminate a finished wine. Hopefully, proper sulfur dioxide levels should keep this microorganisms at bay.
For all of these reasons, as the wine has the opportunity to come in contact with existing microflora on processing equipment, wine is bottled in a sanitized environment.
Remember proper sanitation is primarily having good cleaning protocols. Cleaning should always precede sanitation. Failure to physically remove all of the debris from equipment, results in an inability to properly conduct sanitation procedures.
There are several different detergents (cleaners) and sanitizers that wineries can use effectively. Example sanitizers include quarternary ammonium compounds (QUATS), peroxyacetic acid, chlorine dioxide, hot water, and steam. Additionally, wineries can find use in an acidulated (citric acid) sulfur dioxide mixture. However, all sanitizers should be selected specifically for the job at hand (Iland et al., 2012) with consideration towards the microbes that one is trying to avoid.
Most commercial wineries can really focus on improving cleaning practices to provide a step in the right direction towards improving quality and sanitation practices inside the winery.
If you think you may need some help in obtaining winery sanitation basics, please refer to this Northern Grapes Webinar by Randy Worobo on YouTube. Or check out this PodCast by Hans Walter-Peterson and Chris Gerling from Cornell: Winery Sanitation Presspad Podcast, which focuses on preparation for harvest and including sanitation in that prep.
Cleaning harvesting equipment
While this is usually one of the places winemakers feel most complacent about, I would argue that this can be one of the most important places to take care in your cleaning and sanitation practices.
- There is a lot of effort that goes into the growing season in order to adequately ripen wine grapes for many sensory nuances. Additionally, the vineyard is the source of many microorganisms that enter the crush pad and cellar. [For those that use mechanical harvesters, do not forget cleaning and sanitation of this vital piece of equipment (Pregler 2011).] Giving the grapes a clean surface to encounter upon entering the winery ensures that all of that hard work is truly appreciated and preserved from the start of fermentation.
- Without proper cleaning and sanitation practices, you are likely increasing the microbial populations of your wine before it even gets a chance to ferment. Think about it. After crushing/destemming a lot of rotting Pinot Grigio, Pinot Noir, or botrysized Riesling, how many people spray down the equipment (lightly) and move onto crushing the next lot of fruit even if the second lot is cleaner than the first? Sometimes, the order of grape crushing cannot be avoided. But how it is handled upon receiving can be altered. If this is the case for your winery, and you are avoiding good cleaning and sanitation steps in between lots of fruit, you are cross contaminating your juice with, not only yeast and bacteria present in the rotted fruit, but also residual enzymes, proteins, and other by products that can alter wine chemistry in the clean fruit that follows. Think about the potential production problems this can cause later on down the road: laccase browning, acetic acid development, off-flavor development, etc. If such problems arise, it can cause labor and financial investment at a later time.
- Residual foodstuffs (e.g., old grape skins, rice hulls, pulp) can contribute to off flavors within the finished wine. Recent research has shown that there is potential for aromatically-intense varieties (i.e., Niagara, Concord, or Noiret) to leach their flavor compounds into more neutral varieties through absorption and diffusion of equipment-based plastic components that come in contact with the juice and wine (Smith 2014). It is also possible for alien material (i.e., green matter, old rice hulls, and stuck fruit) to contribute to flavors in the final product that may be undesirable or challenging to fix.
- Remember that rice hulls are a pressing aid primarily used for A) hard-to-press varieties to increase yield or B) bulk operations in which pressing time is of the essence. Previous studies, such as the one found here, have shown a detriment in flavor and quality of wines pressed with rice hulls for certain varieties. Additionally, rice hulls can be difficult to remove from the wine press and create potential microbial infection sites for later grapes/juice/wine. It is recommended that the use of rice hulls be on aromatically intense or difficult-to-press varieties (e.g., many native varieties). Use of rice hulls in grapes that have a lot of rot will not only help increase yield of the fruit, but also increase extraction and retention of rot byproducts, which can contribute to off-flavor development.
- Proper cleaning can help maintain your equipment longer. Over time, plant material can slowly degrade equipment. Doing a little scrubbing and properly sanitizing repeatedly can help keep your equipment in relatively good condition. Additionally, the longer debris is left on equipment, the harder it is to remove.
Properly maintaining harvest equipment also leads a good example for all of the other equipment in the winery.
Tanks, Barrels and Bottles
These are places in the cellar where it can get easy to take short cuts as opposed to properly cleaning or sanitizing equipment.
These are places in the cellar where it can get easy to take short cuts as opposed to properly cleaning or sanitizing equipment.
- Remember that tartrate build up in tanks and barrels can make it difficult to properly sanitize the covered portion of the tank/barrel. Make sure to first dissolve large tartrate deposits with hot water before going through a cleaning and sanitation cycle. Without dissolving tartrates, the equipment is not going to get properly cleaned or sanitized.
- When getting ready to fill a tank, remember to run a sanitizer through the tank first to minimize microbial populations on the interior surfaces that come in contact with the wine. This helps ensure varietal flavor nuance and minimizes the risk for spoilage. [Note: Some sanitizers are no-rinse sanitizers and do not require a rinse after the sanitation chemical is applied. Other sanitizers may require a rinse following application. Always check the directions pertaining to your sanitizer carefully before use to ensure it is being used properly for best efficacy, and always use proper protective clothing when handling sanitizer agents.]
- Minimize harboring sites for insects and microbes within the cellar are a practice that can be done at the end of every shift. During harvest, one big problem I see is dripping, dried juice or wine on the exterior of tanks or fermentation bins. While this doesn’t seem like a big deal, it’s an attractive site for fruit flies, which also makes them attractive deposits for spoilage yeast and bacteria. The objective of removing these places of dried juice/wine is to minimize insect infestation in the winery and avoid potential contamination of clean wines.
- Barrels need cleaned prior to sanitation regimes like other pieces of equipment. Many barrel cleaning systems are automatic and can be an efficient way to clean the interior of barrels.
- Barrels are porous and have a lot of grooves inside of them, which can make it difficult to properly clean and sanitize. It is important to note that due to the nature of the barrel, it cannot be sanitized in a way that a stainless steel tank can be sanitized. However, there are many different cleaning and sanitation options for barrels out there, some of which are explored in this Appellation Cornell newsletter from 2013. This study evaluated natural barrel microflora (yeast, including Zygosaccharomyces and Brettanomyces) before and after a sanitation regime was conducted.
- Sulfur wicks are a good way to treat the interior surface of the barrel, but this practice does not penetrate into the interior of the wooden staves (Iland et al. 2007). Also, ensure that the wick is not submerged below any left over water at the bottom of the barrel, as it may extinguish the wick (Iland et al. 2007). Make sure the bung is tightly sealed for best efficacy of a sulfur wick (Rieger 2015).
- Bottling lines are not immune to cleaning. In the food industry, it is commonly noted that most contamination comes from the environment in which the food is processed. This can happen in wine processing, as well. Dust on the bottling line can harbor yeast and bacteria that can be disturbed or moved into the air during large movements, like when bottling a finished wine. Keeping the bottling line clean is a good way to help minimize contamination during bottling operations.
Small Steps That a Commercial Winery Can Take to Improve Cleaning and Sanitation
Being a smaller or boutique sized winery can definitely have its advantages in the cleaning and sanitation world. It’s easy to get creative in terms of improving efficiency, use of, and efficacy of cleaning and sanitation practices. Below are some practical solutions for wineries struggling to incorporate cleaning and sanitation practices in the winery.
Use brushes, like Perfex brushes, to properly scrub equipment during cleaning operations. These are especially helpful when getting that pesky debris off of processing equipment.
Color code brushes or cleaning materials to emphasize their use and make it easier on your employees. By keeping the necessary supplies handy and easy to use, efficiency is likely to improve, which can actually help improve the quality of cleaning operations. Typically, white brushes are reserved for food-contact surfaces (the part of the equipment that actually comes in touch with food) during sanitation steps. Yellow brushes can be used for environmental cleaning (non-food-contact surfaces like the exterior of tanks). Other colors can be purchased for additional specific purposes: detergent only, sanitizer only, etc. Keep the brushes handy during all processing operations.
There is a great article from Food Engineering on the power of color coordination in the food industry, which you can read here.
Consider keeping your cleaning and sanitation system on wheels. While in Oregon, I found it clever how larger wineries kept their fittings on mobile units to aid in availability, cleaning, and organization (Figure 3). While this concept may be helpful to some wineries, I think it can also be applied to cleaning materials. Keeping cleaning materials isolated to a mobile until allows for quick use and organization throughout the entire production facility and minimizes needless travel time to walk back and forth towards where supplies may be kept. Examples, below, for how to improve mobility of your cleaning supplies are given in Figure 4.
You do not need to use fancy (or expensive!) cleaners or sanitizers all of the time in the winery. For quick clean ups, use warm water mixed with potassium carbonate to get stuck or sticky material off of equipment. Use with caution as it can get slippery!
Follow a potassium carbonate rinse with a warm water rinse to remove the solution from equipment and environmental surfaces.
Acidulated sulfur dioxide (Figure 5) can act as a quick sanitizer as well, and is easy to make up and use in the winery. Plus, citric acid, sulfur dioxide, and water are found in wine and will not have an effect on wine quality or flavor.
Finally, I always recommend wineries keep a supply of 70% ethanol in a spray bottle handy for quick cleaning solutions. Ethanol can be used to clean up small spills, quickly rinse sampling valves before and after sampling, or act as an exterior sanitizer towards things like wine thieves, sampling pipettes, and lab benches where one is running analysis. This is an easy chemical to keep on a mobile cart or scattered throughout the winery. However, be sure to purchase food grade ethanol from a chemical supplier and dilute down to ~70% with non-chlorinated water.
Cleaning up at the end of a processing day makes the start up for the next processing day a lot easier. If the equipment is clean to start, then all you have to do is run a quick sanitizer through the equipment before the start of processing operations.
Use hot water to rinse your equipment and make sure your hose has good pressure. Cold water is definitely energy efficient, however, hot water can help remove a lot of debris quicker and make any potential scrubbing easier. Be cautious of the metal on equipment heating up with use of hot water. Also, increasing hose pressure can help dislodge any debris from equipment, which can save time during cleaning operations.
On large processing days (those days when 3 or 4 varieties are being crushed at the winery), designate the day to processing and wait until the next day to complete other operations that can be delayed. Now, some flexibility needs to be made for things like punch downs or pump overs. However, teamwork is key: punch down time can be reduced if there is more than one punch down tool available for employees to use. Juice analysis (pH, TA, Brix, and YAN) is time sensitive, because if the juice starts going through spontaneous fermentation, the results of these chemical indices will change. However, obtaining all of the juice samples from all lots of incoming fruit before starting analysis can save your employees time and avoid splitting up duties during a processing day. With 3 employees, one person could run analyses while the remaining 2 finish cleaning up at the end of a processing day. Reserve racking or moving wines for days when a little less is going on in the cellar unless it is absolutely necessary to open up space in tanks for incoming fruit.
Minimize barrel-to-barrel or tank-to-tank contamination by having small sanitation vessels/buckets (filled with sanitizer) handy and isolated for cleaning/sanitation use. Use a bucket filled with acidulated sulfur dioxide solution to submerge (and fill) your wine thief in prior and after each barrel sample. For smaller samples, consider using one-time-use or disposable pipettes (Figure 6). If you have a 70% ethanol solution in a spray bottle, the metal fittings at the end of hoses can be quickly sprayed in between barrels when transferring barreled wine into a tank or transferring wine from a tank into barrels to help minimize cross contamination (Illand et al. 2007).
Check to see how clean your equipment is with quick testing strips like Pro-Clean Protein Residual testing strip by Hygiena. These testing strips are a good indicator on how well your cellar crew is cleaning equipment. The problem with protein test strips, like the one shown, is that it will detect all organic matter (Iland et al., 2007). It does not represent live or viable microorganisms; there are rapid tests available that may be more representative of microorganism populations.
The video below indicates the ease in which these are to use:
Other options include luminometers like Hygiena’s SystemSURE Plus or 3M Clean-Trace (Rieger 2015), which are also non-specific, but can indicate the cleanliness of a contact surface that is swabbed properly.
While cleaning and sanitation may seem arduous, most wine quality problems I encounter – including funky off-flavors that are challenging to identify, presence of VA, large quantities of wine affected by cork taint, and lack of varietal character – could be primarily avoided with more routine and better cleaning operations. Improving cleaning and sanitation operations can be a step in the right direction for wineries to improve quality associated with their business.
Iland, P., N. Bruer, A. Ewart, A. Markides, and J. Sitters. 2012. Monitoring the winemaking process from grapes to wine: techniques and concepts. 2nd Ed. Patrick Iland Wine Promotions Pty Ltd. Campbelltown, Australia. ISBN: 978-0-9581605-6-8.
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. Campbelltown, Australia. ISBN: 978-0-9581605-3-7.
Pregler, B. Nov 2011. Industry Roundtable: Cellar Sanitation. Wine Business Monthly.
Rieger, T. Oct 2015. Microbial Monitoring and Winery Sanitation Practices for Quality Control. Wine Business Monthly.
Smith, JC. 2014. Investigating the Inadvertent Transfer of Vitis labrusca Associated Odors to Vitis vinifera Wines. Retrieved from Electronic Theses and Dissertations for Graduate School: Penn State: https://etda.libraries.psu.edu/catalog/23501.
Solis, M.L.A.A., C. Gerling, and R. Worobo. 2013. Sanitation of Wine Cooperage using Five Different Treatment Methods: an In Vivo Study. Appellation Cornell. 2013-3.
By: Andy Muza, Penn State Extension – Erie County
Another harvest will soon be over for grape growers in Pennsylvania and the winter season is fast approaching. Take the time this winter to explore the resources below to prepare for next season’s pest problems.
The following 5 references provide information on identification and management of insect, disease and weed problems in vineyards. I suggest purchasing these items before next season begins. Although the cost will be over $250 it is well worth having these invaluable resources in your viticultural library.
- New York and Pennsylvania Pest Management Guidelines for Grapes: Every commercial grape grower in Pennsylvania should have a copy of the current guidelines. This guideline provides a wealth of information on insect, disease and weed management with pesticide options, rates, and schedules, as well as, a chapter on sprayer technology.
- A Pocket Guide for Grape IPM Scouting of Grapes in North Central & Eastern U.S.:This pocket reference book is for use while scouting in the vineyard. The guide provides concise information and color photographs on insect/mite pests, natural enemies, diseases and disorders.
- Compendium of Grape Diseases, Disorders, and Pests, Second Edition: This new edition is an expanded version of the original Compendium with 375 photos and drawings and containing updated information about pathogens including additional diseases. The second edition is divided into 4 parts covering: diseases caused by biotic factors (e.g., fungi, bacteria, viruses etc.); disease – like symptoms caused by insects and mites; disorders caused by abiotic factors (e.g., environmental stresses, nutritional disorders, etc.); and fungicides/spray technology.
- Weeds of the Northeast: Described as the first comprehensive weed identification manual available for the Northeast enabling identification of almost 300 common and economically important weeds in the region. The manual contains color photos of vegetative and flowering stages of weeds, as well as, seed photos.
- Wine Grape Production Guide for Eastern North America: A comprehensive reference on all aspects of wine grape production (e.g., varieties, canopy management, nutrient management, etc.) including chapters on disease management, insect and mite pests and vineyard weed management.
Insect and Disease Resources – 2016 articles
Articles from the 2016 season that should be reviewed include:
- 2016 Pre-Bloom Disease Management Review by Bryan Hed, Penn State University
- 2016 Post Bloom Disease Management Review by Bryan Hed, Penn State University
- Late summer/early fall grape disease control; 2016 by Bryan Hed, Penn State University
GRAPE DISEASE CONTROL, 2016 by Wayne F. Wilcox, Cornell University (74 pages). Dr. Wilcox provides comprehensive coverage of relative research and disease management options.
Grape Insect and Mite Pests – 2016 Field Season by Greg Loeb, Cornell University (21 pages). Dr. Loeb provides a thorough review of insect pests that you might see throughout the season in the vineyard. Included are 18 photos of pests/injury along with management guidelines.
Insect and Disease Resources – Web sites
IPM –Grapes (Cornell): Information is available on diseases, insect and mites, weeds, wildlife, organic IPM, spray technology and pesticides.
NYS IPM : Fruit IPM Fact Sheets (Cornell): Fact sheets on diseases and insects on grapes, tree fruit and small fruit. A total of 22 fact sheets pertain to insects and diseases on grapes.
Identifying Grape Insects (Michigan State University): The information on this site is from the previously mentioned resource, A Pocket Guide for Grape IPM Scouting of Grapes in North Central & Eastern U.S. and is categorized by: Pests attacking; buds, leaves, fruit, root, during harvest. Also includes beneficial insects and mites.
Mid Atlantic Vineyards Grape IPM (Virginia Tech): Insect fact sheets categorized by: direct pests – fruit; indirect pests – leaves; trunk and cane feeders; and root feeders.
Ontario Grape IPM: This site provides information on a variety of topics including: insects and mites; diseases and disorders; weeds; herbicide injury; identification keys; etc.
Growing Grapes – Vineyard IPM (eXtension): Articles both in English and Spanish on: insects, diseases, weeds, animal pests and problems not caused by insects or diseases.
Weed Resources – Web sites
New Jersey Weed Gallery (Rutgers): Photos and descriptions of weeds found in New Jersey. Weeds can be viewed by common name, Latin name or thumbnail images.
Weed Identification Guide (Virginia Tech): These pages are intended to aide in the identification of common weeds and weed seedlings found throughout Virginia and the Southeastern U.S. The weed pictures are arranged alphabetically by common name.
UMass Extension Weed Herbarium (University of Massachusetts): Identification notes and color photos of over 500 weeds.
UC-IPM Weed Photo Gallery (University of California): Common names link to pages with weed descriptions and photos often showing several stages of development.