geing wine in oak barrels turns a great wine into an exceptional wine, with complexity and textures not possible with other methods. However, if not managed properly, oak barrels can also undo a lot of hard work in the vineyard and on the crush pad. Without adequate protection, microbial activity and oxidation can degrade the wine’s quality.
One of the most common ways to protect barrel-ageing wine is to maintain sufficient molecular sulfur dioxide (SO2) levels. Yet, since every barrel is a hand-crafted, unique vessel, differences arise in how the SO2 protection holds up. This, in turn, affects the quality of wine in individual barrels.
This article outlines a premium estate winery’s experience working with BarrelWise to track and manage free SO2 (and thus protect the wine’s quality) on a barrel-by barrel level, and how this has become their new standard for barrel management.
“Working with BarrelWise to help protect our wines is a great investment. Not only protecting our asset but also ensuring that we are making the highest quality of handcrafted wines possible.” - Paul Gardner, Proprietor
Pentâge is a boutique winery located near Penticton in BC’s Okanagan valley. The winery features world class wines, a beautiful 5,000 square foot natural rock cellar, and incredible views of Skaha Lake. The proprietors, Paul Gardner and Julie Rennie, have planted several rare varietals and produce fantastic small lots of Tempranillo, Roussanne/Marsanne, GSM, Cab Franc, among several others. The winery is also renowned for its Pentâge and Hiatus red blends. The Pentâge team ages much of their wine in barrels, utilizing both French and American oak from a variety of coopers. The barrels are serviced in place rather than forklifted from the stacks.
Traditionally, and as is typical in the winemaking industry, the winemaker would track sulfites by taking samples of select barrels using a wine thief and blend them together to form a composite sample. The winemaker would then use an aeration-oxidation (AO) apparatus to measure the concentration of free SO2 in this sample. The result is used to make sulfite addition decisions across all barrels. This method is imperfect – it relies on averages from a sub-set of barrels and obscures the variances that develops within barrel groups, as well as individual outliers that require customized additions. However, it is the only viable approach for most wineries, since the AO analysis takes 15 minutes per sample, making it impossible to sample all barrels individually. So, just like the other wineries, Pentâge was forced to work with limited information when managing the health of its barreled wines.
As a former marine engineer, Paul has always been both knowledgeable and enthusiastic about new technology. In July 2020, while researching ways to further improve the winemaking practices at Pentâge, he came across the BarrelWise Barrel Management System (BMS), which enables efficient wine barrel sampling, topping and sulfite addition. Shortly after, BarrelWise bungs were installed on Pentâge’s barrels and the BarrelWise team was hired to visit the winery every month to assist with managing the winery’s barrel program.
A key part of BarrelWise’s product offering is its proprietary rapid free SO2 sensor that is designed for measuring sulfites in individual barrels quickly, easily, and accurately. This sensor was brought to Pentâge and used to analyze samples of wine from every barrel for free SO2.
Because of the operational challenges of analyzing and treating every individual barrel in a winery cellar, free SO2 levels inevitably vary from barrel to barrel. This phenomenon has been observed by BarrelWise in every winery the company works with. Pentâge was no exception –the analysis identified several barrels that required the winemaker’s attention to correct the imbalances. Sulfites levels in wine must be balanced: persistently low levels of free SO2 can expose wine to an increased risk of oxidation and microbial spoilage; at the same time, too much SO2 will eventually affect the wine’s taste.
The data, collected by BarrelWise and presented in an interactive report, enabled Pentâge to carry out targeted sulfite additions, and provide optimal protection for its barrel-ageing wines, while keeping its sulfites use as low as possible.
The variability of the free SO2 levels between individual barrels was not a surprise to Paul. Now that he had the barrel-by-barrel data, the Pentâge team were able to make custom sulphite additions and maintain freeSO2 levels close to desired set point for each barrel with no winery laboratory time required. The custom additions targeted barrels that were low in free SO2, while leaving barrels that were high to naturally fall towards the desired set point. An example of three barrel groups at Pentâge winery, each with their own desired set point, is shown below before and after custom targeted additions were made with the data from the BarrelWise sensor.
This precision gave the winemaker and owners a much greater confidence that their wine is properly protected, and that they are producing the best wine possible with the fruit from their fantastic vineyard. As a result, Pentâge was happy to sign on for ongoing monthly service. In the owners’ words, “With the value of the product in our red wine barrel program this is a no brainer”.
To date, the variance in free sulfites across individual barrels which was uncovered, and is now being carefully managed at Pentâge, has been a commonplace problem in the winemaking industry. After analyzing over 1,000 barrels across many barrel groups, at multiple wineries, BarrelWise found that ~15% of barrels end up more than 10 ppm away from the group average free SO2 reading during the ageing process. Results of a composite sample, or samples from a random sub-set of barrels, as commonly done in the industry, obscure this variance. The fixed sulfite additions, made to all barrels in a group based on these average readings then exacerbate the problem by chronically underdosing barrels that are low (and at risk of spoilage), and overdosing the barrels that are high (sulfites may start to affect the taste).
Barrels that have sulfite levels outside of optimal are at higher risk of quality issues. They may affect the quality of the overall blend, leading to lower wine ratings and customer satisfaction. This outcome may damage the winery’s brand. To avoid this, the lower quality barrels may be downgraded to lower tiers, targeting less sophisticated consumers and lower price points. But then the revenue potential is also reduced.
Every time a winery spends money on growing or purchasing premium fruit, premium oak, perhaps amore resource intensive barrel work regime (e.g. more frequent racking, or ageing on lees), yet in the end has to settle for a lower price point due to quality issues, it suffers as a business.
BarrelWise solution enables wineries to minimize this risk. Keeping track of barrel-by-barrel data can help to avoid expensive downgrades by catching and addressing any problems early, and maximizing the revenue potential of every barrel.
Free SO2 variance between barrels is widespread in the industry. Wineries typically use barrels of varying ages, oak types, toasts, and sizes, all of which contribute to this variation. Wines from the same fruit and same fermentation, aging indifferent barrels can have drastically different characteristics. But this variance also creates opportunities for quality losses through over-oxidation or unnoticed microbial activity. New technologies like the BarrelWise system are allowing winemakers to easily and efficiently collect barrel-by-barrel data so that these potential issues can be corrected. This helps to reduce the frequency of barrel downgrades and the profit losses that that come with it.
Paul sees a lot of value in leveraging modern tools to better safeguard the quality of his wines: “Working with BarrelWise to help protect our wines is a great investment. Not only protecting our asset but also ensuring that we are making the highest quality of handcrafted wines possible.”