What We Find
Why Dry Ice?
Wines & Vines
Wine Business Monthly
Vineyard & Winery
Super Sonic Sanitation
Dry Ice Blasting for Sanitizing and
Restoring Wine Barrels
Sep/Oct. 2006 issue of Vineyard & Winery
Story by Amy Mumma
In the wine industry today, winemakers are fortunate that technology to maintain and improve wine quality is readily available. One such example of a cutting-edge technique is dry ice barrel blasting.
Experienced winemakers will agree that proper sanitation is critical to making quality wine. One issue that plagues the industry is spoilage in barrel. Problems range from residual wine in the wood, high levels of volatile acidity to bacteria, yeasts and mold.
The wood sugar, celliobiose, which is created during the toasting process, is a virtual feeding ground for Brettanomyces. There are a number of commonly used techniques for barrel sanitation, including hot water rinsing, sulfur dioxide and ozone treatments.
Asset management is a top priority for all wineries, including small wineries with limited budgets to large wineries that use anywhere from 1,000 to 25,000 barrels every year. With the cost of new barrels ranging anywhere from $400 to $1,800 each, barrel rejuvenation is a viable option.
While some barrels are just destined for garden planters filled with multi-colored geraniums, many others may go on to lead useful lives with the proper care.
Traditional rejuvenation programs include shaving, scraping, and sanding to remove the outer layer of wood inside a barrel. The barrel may then be used as an inert storage vessel or re-toasted. Unfortunately, if done improperly, this second toasting can often impart a burnt character and off odors such as tar and rubber.
According to George Moskowite of Moss Creek Winery, barrel blasting will definitely affect the quantity of oak barrels purchased. "Traditionally, we buy 50 to 60 new barrels each year. With barrel blasting, I foresee buying fewer barrels on an annual basis because I'll be able to reuse my existing, clean barrels. From a cost standpoint, barrel blasting is fabulous. you get clean, inspected barrels in which you can confidently store wine."
Bob Flook and Vic Vasquez are the principals of Barrel Blasting by Cryo Clean. Flook has a background in automotive engineering and fabrication, while Vasquez has skills in semiconductor welding and worked as a sales representative for Cold Jet, the leader in dry ice technology. Flook and Vasquez started the company in 2000 using new technology incorporating propelled dry ice. Cold Jet retrofitted their equipment for Cryo Clean, and the process was first used for mold remediation projects in hospitals, and sanitation and maintenance for bakeries and other food processing companies.
DRY ICE BLASTING
Cryo Clean Inc. based in Napa, California has developed an innovative
system combining both sanitation and rejuvenation of wine barrels called
Rajeunir, which is French for "rejuvenate." It uses dry ice blasting for sanitizing and restoring wine barrels and is EPA, USDA and FDA approved. It is the name of the machine, but also encompasses the new technology and operator experience and expertise, and it is patent pending.
Dry ice blasting uses solid carbon dioxide pellets propelled at supersonic speed toward the inside barrel surface. The result is removal of tartrates and contaminants without any abrasion of the surface. The dry ice at -79C (-110 F) creates a temperature shock and a transfer of energy upon impact. The dry ice pellets explode on the surface and quickly warm to carbon dioxide gas, harmless in the small amounts used.
The explosion on the surface cracks and delaminates the tartrates and contaminants while the gas quickly expands and forces them off the barrel surface from underneath. The contaminant, now rendered unconscious, falls off. The dry ice completely dissipates, leaving only the contaminant and no secondary waste, chemical residue or off flavors.
Flook credits Gallo of Sonoma as instrumental in giving guidance with the original testing of the dry ice blasting process. "Gallo has played a huge role in aiding in the testing process and providing direction and suggestions." The principals also looked to barrel experts to gain knowledge and were trained by such companies as Barrel Builders in Napa. Through listening to winemakers and other industry professionals, along with repeated testing, they created a procedure that has proven successful in both sanitation and rejuvenation.
Barrels at F. Teldeschi Winery were treated with Rajeunir system. On the topic of tartrates, Assistant Winemaker Bill Wertzberger states, "The removal of tartrates is most notable when racking. No old tartrate deposits are coming loose into your new wine, and maintenance and washing are quicker and easier.
Norman Beko from Cottonwood Canyon Winery was also satisfied with the results. "It gives me great satisfaction and peace of mild to know that I can confidently store my wine in these freshly blasted barrels, maintaining the integrity and high quality of my wines."
In conjunction with sanitation, the process may be used to open up the grain of the wood exposing new toast. Barrel blasting only removes approximately fifty thousandths of an inch of wood, opening up the wood, increasing the surface area, and allowing more wine to reap the benefits of the original toast of the barrel. A heavy toast will require a stronger blast to reveal fresh wood, while a lightly toasted barrel needs a softer touch so no raw wood is exposed that may detract from the wine.
Part of the magic of the process is leaving the original toast intact. Barrels treated by Cryo Clean are not re-toasted. This technology helps prevent the need of re-toasting of the barrel which can lead to burnt aromas and off flavors of tar and rubber. After the blasting process it is possible to install new toasted barrel alternatives. Since the dry ice dissipates on impact there is no residue or off taste from the process itself.
On the topic of barrel rejuvenation Wertzberger said "the oak I'm getting from blasted barrels is much better than untreated barrels of the same age. And for someone like me who doesn't like to over-oak, blasted barrels are better than new ones."
The cost for dry ice blasting ranges from $50-$70 per barrel, a small expense to protect the investment while maintaining clean wine. Cryo Clean also offers a mobile on-site service for 50 or more barrels. In addition to use on barrels, the system is used for sanitation and maintenance on inert storage vessels, walls, floors and ceilings of barrel rooms.
LISTENING TO THE CUSTOMERS
Because there are literally thousands of variables and combinations possible in barrels, winemaking and desired styles, each barrel is treated on an individual basis. The operators work very closely with the winemaker and ask, "What is it you want to see?" Operators can adjust the distance, pressure, speed, and other factors to conform to meet each barrel's profile.
A thorough hot water washing and treatment with sulfur dioxide prior to blasting is recommended, and for best results, dry ice blasting should be done as soon as possible after the barrel is emptied.
Each barrel is inspected by operators and evaluated for moisture content, type of wood, grain, pith, toast level, age of barrel and common problems such as Brettanomyces and excessive volatile acidity.
Moisture content of the barrel is extremely important. If the wood is soggy, a lower pressure and propel rate are used so the dry ice does not dig too deeply into the wood's surface imparting raw wood flavors into the wine.
Lindstrom-Dake of Thumpbrint Cellars states, "The phenolic comparison between my wine from new oak and used oak cleaned by blasting is only very slight, at best. In fact, I personally favor the subtleties found in the treated barrels over the pronounced influences from new oak. And, as far as flavors imparted into the Thumpbrint wines, I again prefer the integration of spice from the barrels blasted by the process."
After treatment, the barrel is reassembled by the Cryo Clean cooper, pressure-checked, and sulfur dioxide added at 1,000 ppm. In addition, Cryo Clean offers a service to shrinkwrap the barrel in sulfur dioxide, assuring several months of safe storage.
EXPANDING THE REACH
For all their success, Flook cautions that the process is not a magic cure. "There is no guarantee of results on barrels with excessive volatile acidity or those badly infected with Brettanomyces." Published results and current data are available on their website at www.barrelblasting.com. Trials are being conducted regarding the use of dry ice blasting as mitigation for TCA, but there is no conclusive evidence to date.
"Right now, we are mostly evaluating the results by taste," states Flook. More trials are under way with a number of area wineries to test for Brettanomyces levels and conduct more formal phenolic analyses, such as oak extraction, tannin levels, and flavor compounds.
Because of the unique nature of the process, Cryo Clean is currently in negotiations around the world for franchising opportunities. Flook is quick to point out, "It is not just the machine that makes the difference, but the success depends on the service and experience of our operators." They will train operators who wish to franchise and take the process to other areas and are currently training an operator to work in Washington State.
It is a system that is an example of smart asset management and sustainability, along with helping to ensure a clean vessel that adds the desired components into the wine.