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Choosing the Best Method for Sanitizing Barrels

Choosing the Best Method for Sanitizing Barrels

Choosing the Best Method for Sanitizing Barrels

Which method is best for your winery's logistical and budgetary requirements?

by Michael S. Lasky
Dec 2015 Issue of Wine Business Monthly

Robert Tracy, proprietor of BevTrac Mobile Quality Systems, a quality assurance/quality control service, performs periodic sanitation audits at wineries to test whether barrels are actually microbe-free after their washing routine. “I scrape the interior of barrels and collect wood shavings after their normal cleaning and sanitation processes. I take those shavings back to the lab, soak them in saline then plate onto petri plates to look for any wine spoilage microbes,” Tracy said. 
From his quality assurance perspective, Tracy thinks it’s a good idea for winemakers to check their barrels quarterly or semi-annually. When asked about the relative results he has found from barrels treated with an ozone solution or steam, Tracy said, “Steam seems to be the best at knocking back the microbes in barrels.

 Article on the original page

 Every winemaker is well aware that there are two basic reasons why their barrels need a regularly scheduled washing: to remove Brettanomyces (Brett) and other microbial contaminants, and to remove tartrate crystal accumulation to keep the wood exposed to the wine.

With the cost of an American or European oak barrel ranging anywhere from $400 to $1,200 or more, let’s face the harsh truth: maximizing a barrel’s life span is not just so a winemaker can produce good wine. It’s just as much about maximizing a winery’s return on investment. Washing, therefore, is an important part of any barrel maintenance program.

While some wineries still rely on chemical-based barrel cleaning, wineries have now mainly settled into two camps—those that prefer cold or hot ozonized water flushes and those that steam clean their barrels. Also to be considered are other available methods of extending barrel life, such as dry ice blasting and the no-water-needed ultraviolet (UV) cleaning solution.

With numerous cleansing methods available, choosing the right one for your winery can be tricky. A high adoption rate among wineries may validate the obvious quality of products; however, the popularity of one cleaning method over another is still subjective. What became clear from discussions with those who offer barrel cleaning solutions was the division between those companies that believe cold or hot water and ozone (pressurized or not) are best for barrel health versus the rapidly expanding camp that praises steam heat as the best barrel cleaner and sanitizer.

The Argument for Ozone

John McClain, president of McClain Ozone, pioneered the use of ozone for barrel cleaning more than 20 years ago. “When you get a barrel contaminated with Brett, you want to do two things. One, you want to kill the microbe in the barrel. Secondly, you want to get rid of the metabolic byproducts, which create the taste and odor issue in the barrel,” he said.

McClain referenced a study out of Fresno State University that reported ozone penetrates oak about a quarter of an inch, so the spoilage organisms that the wine industries are concerned about are essentially aerobic critters. “When you use ozone on a barrel, you get a good penetration on the wood using cold water, and you’re not only killing the microbe but you’re getting rid of the metabolic byproducts. You’re oxidizing those byproducts away, so the barrel smells good when you’re done,” McClain said. He added that their cleaning protocol in drought conditions uses half the water that their clients previously used. “What we do is run ozonated water through an ozone compatible pressure washer to a high-pressure cleaner and then use cold water to clean and sanitize. It takes half the time and half the water,” he said.

McClain argues that ozone gas is a better solution for barrel storage than sulfur dioxide, which can linger inside a barrel. Ozone, on the other hand, degrades to pure oxygen.

“We have had great success with ozone,” said Janet Myers, general manager and director of winemaking at Rutherford, California-based Franciscan Estate Winery and Mount Veeder Winery. “We have found ozone to be very effective for sanitizing our barrels. First we rinse the barrels in 180° F, then we switch to 150° F for three minutes for each cycle. Then we apply the ozone for 75 seconds via mechanized, high-pressure washers. The ozone is mixed with water at around 5 to 6 ppm.

“Because ozone has worked so well for us, I have not felt the impetus to switch to steam. We also reuse the water. It is sent to a waste pond where it can be used to water our landscaping. The ozonated water is also recaptured and can then be used to clean floors and other areas of the winery,” explained Myers.

Franciscan Estate (part of Constellation Brands) has about 27,000 barrels, according to Myers. She noted that barrels are kept for about six years and in that time may get three or four uses and are cleaned between each use. The barrels are treated with ozone outside the winery, where there is plenty of fresh air so there are no issues with accidental ozone inhalation by workers.

The Argument for Steam

Mark Grote, regional sales manager at ARS Enterprises, which manufactures the SWASH steamer and pressure washer equipment, said, “By adjusting the time steam is on the wood—between three to eight minutes—you can control the amount of extraction on the barrel. I have gotten repeated unsolicited comments from wineries that if they steam a barrel from its first use, they actually get more life out of the barrel. They found that the oaking of the barrel is more consistent and predictable.”

“The average Cabernet producer keeps their barrels for three years and then they’ll usually sell them off,” Grote added. “A lot of wineries are telling me they’re getting another year, year and a half, two years out of the barrels that they weren’t getting before because they found out that the oak wasn’t depleted. The oak was plugged up. The difference between French oak and American oak is that American oak has a very open cell structure with big pores. French oak has small pores so tartrates deposited in these barrels plug up those small holes very easily and you can quickly lose about 50 percent of the barrels ability to oak your wine in as little as one vintage.

“If you’re steaming in a barrel, even just once a year, not only are you maintaining any microbiological level of cleanliness that you want in the barrel, but you’re also pulling all those little tartrate plugs out of the wood,” Grote explained.

Santa Rosa, California-based Punchdown Cellars is a big proponent of steam, according to Robert Morris, president of the winemaking services and logistics provider. “We won’t use ozone inside the cellar anymore. The possible health effects on our workers are not worth using ozone, especially with a steam generator on-site,” said Morris. “Each barrel takes about 5 minutes to clean with steam. If we notice a rear bacterial contamination we will steam for 10 minutes.”

“Steam has saved us thousands of gallons of water,” said Durs Koenig, operations manager at Sonoma Wine Company. “Although steam is pushed out at slightly above 212° F, the accompanying pressurization causes the temperature to go up a bit. It is hard for any organism to survive that. The trick is the right amount of contact time. Accordingly, we have found steam is more effective than using chemicals to clean.”

Aaquatools, Inc. offers both ozone and steam cleaning solutions for barrel sanitation. However, president Steve Buchan said steam has definitely been more popular. At last year’s Wines & Vines Oak Conference in Napa, Buchan said there were a number of highly respected industry people who got up to talk about how they care for their barrels. “Most everybody liked steam,” he said. “Ozone is something that is extremely questionable. We sell ozone. Do I think it’s popular right now? Not nearly as it was.”

Buchan said one reason may be that there are a lot of unknowns in ozone, but there have been some really favorable articles on steam. “I mean, we are just killing it with steam right now.”

Buchan said many of his winery clients will first perform a high-pressure wash and then steam the barrel for the final kill. “When you go in with that much temperature that steam produces, that’s your sanitation process. Now that’s not to say that there aren’t some winemakers hanging in there with ozone rinses. We’re not fond of ozone. I have heard it summed up as the next attorney’s dream because there’s a lot of liability; there’s a lot of degassing in the air. Steam is a much more practical and verifiable way to sanitize the barrel,” Buchan said.

“In all of our barrel processes, there are no chemicals. There’s no gas (ozone) unless somebody wants to buy it. Steam is pretty miserly with water and averages about 8 gallons per hour and it is not just for barrel work but for cleaning all parts of a winery,” Buchan added.

Using Both Steam and Ozone

Since 1983, Tom Beard has been devoted to creating barrel cleaning solutions for the wine industry. As founder and chief engineer of The Tom Beard Company, now part of P&L Specialties, he has been selling a self-contained portable unit (TCB2-US) that cleans and sanitizes barrels with plant-supplied hot and cold water and dissolved ozone water supplied from a separate ozone generator. The wash water is boosted to the necessary cleaning pressure with an integral pump, and fluids are controlled via pneumatically actuated valves and controlled by a touch screen panel.

But as Tom Beard, adapting to winery demands, pointed out, “Steam is gaining in popularity. Ozone was the big deal for a while. They have used steam for a long time in Europe. The European winemakers think that the advantage to steam is that you can steam the barrel and bung it; and as the barrel cools down, the organic matter that’s trapped in the wood pockets is actually pulled out and killed because the steam is over 180° F degrees for some period of time. They actually feel that that treatment is good for the barrels, especially if you have Brettanomyces in your wine, or some other bacteria that you’re trying to get rid of. Initially, here in the last five years it’s been looked at as a sterilizing agent, or a sanitation agent.”

The downsides to steam and ozone? Beard said steam can be very dangerous because you can get scalded with it, and steam generation requires a lot of energy. But ozone can also be detrimental to your health, Beard said. “It won’t scald you, but if you get a real lung-full of it you are going to the emergency room. Ultimately which system a winery uses is a balance between labor, water and time.”

According to Tom Beard Company’s sales and service general manager, Jesus “Chuy” Mendoza, the company is working on a unit that allows both washing and steaming. “We have built some customized equipment for washing and steaming, but beyond these one-off designs, we are working on a wash and steam machine—the TBC2 Steamer—for general sale.” Expected delivery is the first quarter of 2016.

Which Method is the Right Choice?

Adding some academic gravitas to the argument for either solution is professor emeritus of enology at Fresno State University, Kenneth Fugelsang, who thinks steam is a good choice because of its high temperature and ability to penetrate wood. While he thinks ozone is the right choice for the smooth surfaces of tanks, hoses and pumps, it is not that effective in barrels. That’s because ozone has a short half-life and it outgases out of its water solution quickly in the barrel.

Steam saves water but makes up for that with its high demands for electricity. Steam also can possibly scald workers if not applied correctly. Ozone has also proven to be dangerous to workers who breathe it in.

Robert Tracy, proprietor of BevTrac Mobile Quality Systems, a quality assurance/quality control service, performs periodic sanitation audits at wineries to test whether barrels are actually microbe-free after their washing routine. “I scrape the interior of barrels and collect wood shavings after their normal cleaning and sanitation processes. I take those shavings back to the lab, soak them in saline then plate onto petri plates to look for any wine spoilage microbes,” Tracy said.

From his quality assurance perspective, Tracy thinks it’s a good idea for winemakers to check their barrels quarterly or semi-annually. When asked about the relative results he has found from barrels treated with an ozone solution or steam, Tracy said, “Steam seems to be the best at knocking back the microbes in barrels.”

But, Tracy adds, some winemakers who use ozone have a “stigma” about steam, that it extracts color and flavor out of the oak. “I’ve talked to winemakers who say steam actually improved the life of their barrels. But there’s also a group that say steam also negatively impacts their barrels. There’s kind of two camps about it. Whenever I recommend steam, I always say, ‘This is the best method we know that really will reduce microbial populations in the barrels.’ That’s all I would say. I wouldn’t say it improves the lives of barrels because I don’t have any data on that,” said Tracy.

Navigating through all the pros and cons of ozone and steam, the final decision for winemakers must be based on a number of factors, such as the size of a winery, the sheer number of barrels, financial limitations and the winemaker’s previous experiential observations with barrel cleaning regimens.

No-Water-Needed Cleaning Options

Dry Ice Blasting

With water conservation now a major concern, alternative, water-free methods of barrel cleaning are a worthy consideration. Of course, winemakers are often traditionalists, so convincing them to try a new process for barrel cleaning takes some successful examples. Some forward-thinking winemakers are now reporting excellent results with dry ice barrel blasting.

Barrel Blasting owner Vic Vasquez applies his automated, patented, Rajeunir rejuvenation process, which blasts the barrels with recycled carbon dioxide dry ice crystals about the size of a grain of rice.

“We basically remove a thin layer of wood. It doesn’t matter if you’re using hot water, cold water, ozonated water or steam. Whatever you may do to try to clean the surface of your barrel, you’re only going to be cleaning that surface of the barrel. Our process literally removes approximately a millimeter of the old, used-up portion of the toast without having to re-toast,” explained Napa-based Vasquez.

“If the winery has a larger quantity of barrels justifying sending our equipment and the entire team, then we’ll do that. If it’s smaller quantities of barrels or depending on the distance that they are, we can pick up and bring the barrels back to our location and clean them there. It just depends on the situation of the winery and the quantity of barrels,” said Vasquez.

“Most importantly, 30 percent of the wine barrels that we open have blisters. They’re holding wine, wine residue, cleaning chemicals, or a combination of all three. Virtually all of them are holding the first vintage, some of the second vintage, and possibly some of the third,” Vasquez explained. “We’ve got special tools that we’ve made that shave these blisters open to relieve that pocket, and let that wine drain out. Imagine you have a two- or three-year-old barrel, and you’ve cleaned it. It’s got a blister in it that’s holding a glass of wine. You go in and you steam it. Steam is great for microbial, but it’s horrible for cleaning those inside blisters. We put it on our automated system. It goes through and blasts with the dry ice. We go through 15 to 20 pounds of dry ice per barrel,” he added.

One convert to Barrel Blasting is Steve Reynolds, owner/winemaker of Napa-based Reynolds Family Winery. “Barrels do get used and the life leached out of them, oftentimes their faults masked by access. The process of barrel blasting opens up the barrel to view its faults, such as blistering or impurities, so they can be scraped clean and addressed first hand—no Band-Aids. The blasting itself then opens the pores and sterilizes the surface to a whole new level, in some ways adding to the flavors. With the addition of stave inserts the barrel is, in my opinion, 90 percent as good—and sometimes 100 percent as good—as a new barrel in a blind tasting,” said Reynolds.

Seconding Reynolds is Julie Johnson, owner/winemaker at St. Helena-based Tres Sabores Winery. “We realized that while some barrels had their first Barrel Blasting treatment, a handful were being rejuvenated for the third time. With the past two harvests being big ones we needed to reserve and reuse more barrels than we had originally planned to and looked to Vic and his team to provide their services,” said Johnson. “Whether you have to use particularly old barrels, or just love using neutral barrels, there is nothing like using barrels that have been revitalized by the Barrel Blasting methods.”

BlueMorph Ultraviolet (UV) Sanitation

The future of wine cellar sanitation just might be ultraviolet. At least that’s what Alex Farren, CEO of Oakland, California-based BlueMorph, has in mind. Ultraviolet Germicidal Irradiation uses short-wavelength UV light to kill or inactivate microorganisms. It uses light, not water, and application is conducted via mercury vapor lights.

First developed for cleaning wine tanks, the portable UV device weighs about 35 pounds and uses a programmable touch-screen which lets cellarworkers set its timer and easily move from tank to tank. Sanitation times vary based on the size of the tank from three minutes for a 3,000 gallon tank and up. The larger the tank, the more mercury vapor lights are needed.

Now available is a UV unit created specially for barrel cleaning. The BlueMorph UV55 is a handheld ultraviolet light used for sanitizing kegs and drums. The UV55 is designed to replace chemical sanitization methods as well as steam and ozone. The unit fits over any 2- to 3-inch opening, sanitizes 55-gallon drums in six minutes and breaks downs kegs in only 3 minutes.

“I think the advantage of UVC, beyond not using water, is the fact that it’s not an oxidizing agent. So it will have less of an effect on the life span of wood probably than any other sanitizer. Steam is probably the most effective on wood. But, then again, it can dissolve a lot of the flavor components over time. UVC avoids that,” said Farren.

Jackson Family Wines’ senior sustainability manager Julien Gervreau said, “We’re always looking for new technology to help us make the highest quality wine with the lowest environmental footprint. Because water is such a sensitive issue in the regions where we do business, using a UV sanitizing system really made sense to us.”

Gervreau estimates a 70 percent water-savings with BlueMorph’s UVC along with a 60 percent reduction in labor and a 50 percent savings in electrical costs. This new waterless technology is predicted to save 250,000 gallons of water a year at each Jackson Family production facility where it is in use.

BlueMorph has partnered with the Tom Beard Company to engineer and design custom units to fit unique operational needs. Jackson Family Wines was the first winery to successfully test the first available tank system.

(Editor’s note: For a more detailed look at BlueMorph’s UV design read Bill Pregler’s What’s Cool column in the October 2015 issue of Wine Business Monthly.) WBM

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