By: Gerald Dlubala
Considering the amount of time wine spends in a tank, whether for storage or fermentation, the type of tank chosen for a winery can play a crucial role in their overall story, branding and image. Whether choosing wood, concrete, clay, stainless steel or something else, each offers unique qualities, options and associated costs. Ultimately, each winemaker’s unique vision and preferred process dictates the type of tank used.
Wood Combines Nostalgia with Utility
Wood tanks remain commonplace in wineries and are still what we envision when picturing a classic winery. The nostalgia and charm of a romantically serene winery with weathered wooden tanks and barrels in the background are aesthetically pleasing, but the usefulness of wooden tanks shouldn’t be overlooked. Wooden vessels have a natural insulating property that keeps fermentation temperatures slightly higher. Traditionally, red grape varietals get stored in wooden vessels during the early stages of fermentation, which wine producers believe allows their wines to develop smoother textures with fewer astringent properties. Deeper red varietals acquire their characteristic aroma and distinctive mouthfeel from wooden vessels. French oak barrels are well suited for adding tannins and promoting the familiar vanilla profile to Cabernet Sauvignon varietals. Pinot Noirs and other classes of lighter wines of the Pacific Northwest also age very well in oak casks.
Wooden tanks and vessels are generally not a locally manufactured product, so it’s critical to keep timeframes in mind when ordering. Another knock against wooden tanks has always been the increased time and attention needed for maintenance, cleaning and storage due to wood’s naturally rough texture and ability to absorb flavors. The good news is that wood tanks are now fitted with many of the same convenience options that stainless steel tanks offer, including larger access doors, top hatches, easily accessible drainage pipes, temperature control plates, thermometers and leveling gauges. With this in mind, wood tanks can be used for decades with proper care.
Concrete: Solid as a Rock
Concrete offers a compromise between the porosity and flavor enhancement of wood vessels and the clean and slick neutrality of stainless-steel tanks. Although concrete was always a valued option for European winemakers, the benefits and advantages of using concrete have now gained favor worldwide, especially in more progressive wineries. Concrete, depending on the formula used, allows for slower oxygen exchanges and slower temperature changes. This more natural fermentation process builds better textures and more favorable aromatic notes. Like wood vessels, concrete tanks can retain small amounts of natural byproducts and yeast from previous uses.
Constant improvement in concrete formulas offers better tank quality and greater size and shape customization. Egg-shaped concrete tanks are popular because of the lack of edges, corners, or creases that encourage stagnation of fermenting liquids. Winemaker’s plans can adapt installation of new concrete tanks, whether that means traditional above ground placement, in-ground or buried placement for enhanced temperature regulation, or even integration into the winery’s physical structure.
Temperature control plates or glycol temperature control systems can be installed in the walls of concrete tanks for protection against any contact with the wine and to prevent hot or cold spots within the concrete tank.
Concrete tanks can be more expensive upfront, especially if the design needs an original mold cast for the concrete pour.
Clay Vessels Remain a Quality Choice
Clay fermentation and holding vessels date back to the Roman Empire, and there hasn’t been a tremendous change in what they can bring to the table in wine enhancement. The natural porosity of clay allows for natural micro-oxygenation, which is beneficial for quality fermentation and bonding anthocyanin to produce better color in red varietals.
Amphorae and Terracotta vessels offer the ability to sweat and eliminate excess moisture without adding the tannins or oak aromas of their wood counterparts. Clay is historically recognized for its unique and exceptional thermal insulation capacity that keeps the contents cool through surface evaporation. The fermentation process in clay vessels is slower than in other tank types, but the temperatures remain steady with no heat spikes to provide a richer and brighter mouthfeel.
As expected, proper and regular maintenance is critical for clay tanks. High-temperature washes can cause any stainless attachments to expand and crack older vessels. Newer clay tanks no longer have that issue and can, like other tanks, use hotter water or chemicals to clean, sanitize and neutralize the tanks when needed. Since clay tanks are generally smaller than other choices, they are easier to move, tilt, tip or maneuver for easier access, drainage and cleaning.
When cared for properly, terracotta and other clay vessels’ superior lifespan is comparable to concrete. There are some vessels in use that have surpassed 100 years of regular wine production.
Stainless Steel Fills all Needs
Because of their simple design that allows easy regulation of temperatures, minimal cleanup and easy sanitization procedures, stainless steel tanks are on their way to becoming the most common storage and fermentation vessel in winery production. Stainless steel tanks are generally produced by local distributors, making them easier to get with less lead time and more cost-effective with less shipping costs. Add in their long-lasting composition, easy resale qualities and value holding properties, and it’s easy to see that stainless-steel tanks are a wise investment.
Other than the required cleaning and sanitization duties performed through automated systems or by hand, stainless tanks require little additional maintenance other than swapping out normal wear parts like worn gaskets when needed.
Stainless tanks are available in various sizes and customizations to fit a winery’s needs, from the boutique and family-run wineries to the large-scale producer, and are more widely available on the pre-owned market. Unlike other vessel choices, separate tanks aren’t needed for the red and white varietals unless the winery produces sparkling wines, which require higher internal pressures in their production process.
Protecting Your Investment, Employees and Legacy: the ONGUARD Seismic System
Proper tank choice helps to nurture and protect the winemaker’s product, but natural events like a damaging earthquake can quickly change that. After a 6.6 magnitude earthquake rocked New Zealand’s prime winemaking region in 2013, Will Lomax, founder and managing director of ONGUARD Seismic Systems, along with an experienced team of structural engineers and designers, developed the first genuine seismic tank anchoring system specifically designed to protect liquid storage tanks from earthquake-related damage and resulting product loss.
Lomax combines his extensive background in winery design and structural engineering experience with the latest cutting-edge design tools and methods to form and use a capacity design approach in protecting the winemaker’s tanks, walls and contents. His system includes using ductile anchors to transfer and concentrate any damage from seismic loading into one small, easily replaceable component.
“You know, years back, building codes were put in place mainly to ensure life safety, meaning employees. Don’t get me wrong, that’s all good and great, but those codes left open and sometimes even encouraged the damage to transfer to property and buildings, as long as human life was preserved. Those structures damaged included wine tanks, and to an owner, the product in those tanks is literally his lifeblood and livelihood,” Lomax said. “We believed that the codes didn’t go far enough to protect a business’s livelihood and devised a cost-effective way for all wineries from boutique-sized and family-owned through the mass producers to protect their tanks and investment from seismic activity, including earthquakes.”
Protecting those tanks becomes even more critical when you realize that many winery tanks are now aesthetically or structurally integrated into the winery’s popular reception areas, tasting rooms and banquet facilities. ONGUARD’s anchoring systems protect the tanks, and nearby people, by offering controlled yielding in both compression and tension throughout an earthquake event and any resulting aftershocks.
“I stood alongside a winery owner after the 2013 earthquakes in New Zealand as thousands of liters of his valuable, hard-earned wine disappeared down the drain due to the damage inflicted on the tanks due to the seismic activity,” said Lomax. “The consequences are so much more than just product going down the drain. It’s been noted that around 75% of a winery’s balance sheet is tied to what’s housed in their tanks. In a case of tank failure caused by seismic activity, you’re not only talking about immediate product loss. You’re talking about an immediate loss of business, the potential of a high insurance deductible, and the loss of future business. Market share is hard to gain, and wineries traditionally have some of the more loyal consumers. But if you can’t produce wine for a year, there’s a good chance those customers will get their wine from another supplier, and you’ll have to try and regain your previous customer base as well as any new customers.”
ONGUARD Seismic Systems partners with tank manufacturers who possess the familiarity, skill and installation knowledge to offer their system on new tank installations. Many insurance companies now offer rate reductions for wineries that install tanks equipped with the ONGUARD Seismic System or those that get the system retrofitted on their current tanks. Retrofitting the ONGUARD System works similar to new installations by partnering with knowledgeable, qualified tank companies to install the system on those tanks currently in place and in use.
“Retrofitting is just reverse engineering for us,” said Lomax. “We thoroughly test and perform strength and load analysis on a winery’s current equipment and environmental conditions. After assessing that data, we can confidently move ahead with a course of action and install the properly sized anchors to ensure tank safety.”
“The unknown variable in many of our installs is when retrofitting a winery’s tanks that are on tank stands,” said Scott Erwin, ONGUARD’s Vice President of Sales. “We know that about 60% of tanks in California wineries are on stands, and those stands are typically not up to current code. So we sometimes have to re-engineer or change the stand design to increase performance and meet code before installing our anchoring system.”
Once installed, there is little necessary maintenance. Lomax recommended an inspection every three years of between 5-10% of the replaceable load cartridges inside of the anchors. If there has been a recorded seismic event, Lomax said they would immediately inspect those cartridges.
“This was easily doable in the early stages,” said Lomax, “But now we estimate that we have over 25,000 anchors inground between New Zealand, California and Oregon, so we’ve developed our own software monitoring system with sensors that wake up with and report on any movement in their assigned tank. Now we get immediate feedback and information on which anchors need inspection and possible replacement.”
Lomax told The Grapevine Magazine they are continually improving the software, with the latest evolution reducing costs in their componentry. It is currently available only in New Zealand, with planned additional rollouts coming in the future. “It really is a structural analysis software, and with it being our system, we can train and license knowledgeable local contractors to use it successfully when any inspections or support are necessary, eliminating the extended wait time for service.”
The cost of installing the ONGUARD Seismic System is minimal, generally adding between 0-4% to the cost of the tank, or between 6-20 cents per gallon based on the tank’s contents and the amount of new-versus-already-available resources for ONGUARD to use in their installations, such as concrete pads and stand viability. These numbers vary because of each winery’s potential to offset installation costs with a reduction in their insurance premiums. ONGUARD Seismic Systems reports a 100% success rate since inception.