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Benching Oak Barrel Alternatives

Winemakers build oak focus through trials

by Kerry Kirkham


  • Many barrel alternative suppliers offer an array of pre-measured oak sample kits for 750ml bench-top trials.
  • As with acid additions or fining, careful attention to detail is necessary when conducting oak product trials.
  • Some test kits relate back to stave form for vintners seeking to use inserts rather than chips or cubes.

A thorough bench-top exploration can elevate the barrel alternative medium by aligning oak options with desired results, and many suppliers offer an array of pre-measured oak sample kits that inspire experimentation. All that’s required is vision, some wine and an oak sample test kit.

Winemakers, on and off the record
Randall Grahm, winemaker and founder of 20,000-case Bonny Doon Vineyard, Santa Cruz, Calif., places every processing step that his wines go through on the back label, including the occasional use of oak chips. A firm believer in transparency, Grahm had no hesitation in openly discussing his use of barrel alternatives.

“My guiding principal is we will use oak chips under certain conditions but always with the maximum discretion, without deforming the true nature of the wine,” he said.

Grahm’s primary use of oak chips is rooted in the belief that wine should touch oak during the fermentation process. “It’s very salutary at that juncture,” he said. For color stabilization and structure, Grahm adds one gram per liter of both toasted and untoasted French oak directly to the fermentor. Though academics may disagree, some winemakers take this approach for the benefit of aldeyhyde formation that brings tannin and anthocyanin pigments together. The other benefit Grahm noticed is that oak contact during fermentation seems to inhibit the formation of sulfides.

David Llodra, research and development director at Oak Solutions Group, Napa, Calif., suggested that another way to extract and fix color is to use enological tannins. Oak Solutions Group’s case studies have demonstrated that the company’s fermentation finishing blend of gallo and ellagic tannins has an impact on color fixation due to a high level of total tannin. The prescribed dosing rate of the group’s product tr ¯u/tan’s f² tannins is 20 g/hL during fermentation in conjunction with a combination of pump overs and drain-and-return, if needed. The objective is to extract as many anthocyanins as possible early in the fermentation along with condensed tannins in the presence of hydrolysable oak tannins—yet another way to promote the bonding of anthocyanins and condensed tannins. A liquid trial kit is available from Oak Solutions Group to put this theory to the test in your own lab.

Aside from using chips during the fermentation stage, Grahm occasionally uses oak chips during the maturation process—but always at a discreet level for the purpose of adding structure. “It’s not meant to grossly change the essential character of the wine in any way.”

When considering using oak chips in premium wines, Grahm is reluctant. “We won’t use oak chips in our premium wines; I can’t articulate why we don’t do it.” He mentions that historically there have been slight difficulties in the control and prediction of the outcome.

Gaining more control
Many barrel alternative suppliers have kits for winemakers to use to conduct focused bench-top trials. Most kits are made for use in 750ml wine samples and consist of measured doses with varying exposure times. Oak Solutions Group offers a sophisticated kit with 12 pre-measured test tubes accompanied by testing protocol instructions and aroma notes. Some suppliers, like Nadalie of Calistoga, Calif., offer a 5L bag-in-box setup for trials. Pronektar, Santa Rosa, Calif., offers a kit that resembles a box of chocolates. Inside lies an assortment of 20 different clear plastic tubes containing oak powder, chips and sticks designed for 750ml samples. The only thing missing is a bow.

Grahm uses 750ml bottles for his bench-top trials but advises that the sample wine be degassed of all CO2 and have the appropriate levels of SO2 to maintain freshness.

Though it is the most common bench-top testing volume, a 750mL test sample size does not fit all. Winemaker X at a 150,000-case winery in Sonoma County, Calif., said, “750ml doesn’t really make much sense for us” when it comes to doing trials for use in the company’s $16 Chardonnay, which comprises the lowest priced tier in the winery’s portfolio. Trials for stave inserts sourced from StaVin and Nadalie are conducted in 55-gallon stainless steel barrels or 3,000- to 5,000-gallon test tanks.

After pressing, Winemaker X allows the Chardonnay to settle for 24 to 48 hours. The wine is then racked off the heavy lees to ferment on lighter lees with oak stave inserts, all while achieving a target turbidity number. In lieu of micro-oxygenation, a pump-activated snake at the bottom of the tank gently stirs the lees every 2 to 3 weeks after primary fermentation and before malolactic fermentation occurs. The wine then stays on the stave inserts until it is ready to cold stabilize and bottle. 

Reusing and storing oak productsMany barrel alternatives can be reused to stretch tight winery budgets even further. However, if you’re going to reuse your products, be sure to get them into wine right away. Don’t let them dry out in an attempt to store them.

StaVin’s oak beans have a useful lifespan of at least one year, allowing them to be used in multiple wines. Beans are cut across the end grain on two sides but maintain the overall structure of the wood. A bean is not jagged like a chip, so it allows for a slower extraction, giving it a longer life in the wine. As you’d expect with a tea bag, the first use will have a quicker extraction rate, so contact time should be adjusted according to the planned reuse rate.

According to Nadalie, most of the company’s infusion products can be reused up to four times. The bigger the size of the product, the more often it can be reused. Chips, for example, can be used a maximum of three times.

Keep in mind the volume of wine that is displaced by a barrel alternative. When you pull your product out, be sure to mind your headspace and top off when necessary.

Unused chips should sealed back up and stored in their original bags in a cool, dry place.

Built on barrel alternatives
Steve Peck, red winemaker at 1 million-case J. Lohr Vineyards and Wines, Paso Robles, Calif., said that J. Lohr is truly a barrel house stacked with 20%-25% new oak. However, J. Lohr’s Cypress label is built on barrel alternatives. Cypress retails between $8 and $9 per bottle and represents less than 5% of total production. Once a year Peck conducts 5L bag-in-box bench-top trials with a 10 gram per liter oak addition. His exposure time ranges from 2 weeks to 2 months. Peck adheres to the 10 gram per liter addition rate because it makes the blending math easy when blending back with neutral wine for the final release.

“It really does challenge the mind as to whether or not that oak sample is representative enough. A 750ml sample is tough to extend to a tank amount,” Peck said in reference to possible translation errors. “It’s tough to base a large purchase upon it.” In Peck’s case, 90% of the alternatives he uses are granular untoasted French oak for color stability and tannin contribution during primary fermentation. After primary and before malolactic fermentation, he uses micro-oxygenation in conjunction with his alternative addition.

After Peck selects his bench-top winners, he conducts trials in neutral oak barrels and selects a champion from there. “Whittle down candidates and scale up the volume. Be clear about what your goals are, because you can get lost in all the options,” he advises.

Dr. Jeff McCord, director of research at StaVin, Sausalito, Calif., has a cautionary word about using alternatives in neutral oak barrels. “The interaction between alternatives and so-called neutral barrels can really throw things off. That’s where you have to be careful, especially when using barrels from different coopers.” For better predictability and repeatability, McCord advises that, if possible, vintners test apples to apples and use the same type of barrel from the same cooper.

McCord said the biggest problem winemakers face in barrel alternative use is overuse. “Many winemakers try to relate the surface area of the barrel to the overall impact of the wine. Barrel alternatives have twice the impact, perhaps even more because you’re extracting the entire surface rather than just the interior of a barrel.”

Weight and time are critical
Jeff Murrell, also of StaVin, said the most important consideration in a bench-top trial is how the product you’re using in the trial will relate to what you’re finally going to use in the production tank. The weight of the alternative used in the trial and the time of extraction have to be carefully controlled to get a clear idea of how it will perform in a production lot. Murrell advised, “Treat it like a fining trial or acid trial. Be careful about weighing out your samples.”

StaVin has three years of extraction data for all of its products, so the company designed bench-top sample kits for a one-week exposure time. By increasing the concentration of oak, the extraction time can be decreased, allowing winemakers to make quick decisions. For the company’s beans or cubes, the oak is toasted as a stave first, then cut into pieces for the ability to relate back to a stave.

For 750ml bottles, Murrell prefers using screwcaps to avoid any possible outside influences. He also said that temperature is a big factor in extraction rates and advised that sample bottles be kept at cellar temperatures (around 60?F), saying that cold results in a slower extraction. The warmer the environment, the quicker the extraction—just like a tea bag. Each alternative has a different extraction rate based on the surface area exposure.

Phil Burton, owner of Barrel Builders, the Calistoga-based cooperage, suggests, “Don’t go by one or two samples. You have to do repeated trials—at least three or four trials per adjunct. One of the problems is, you’re dealing with subtle differences. The resulting wine is open to a lot of interpretation.” Burton also suggests that multiple tasters experience the samples, and that tastings always be blind to prevent the chance of falling in love with a famous brand name or captivating product image.

Greg Kitchens is the winemaker at 1 million-case Don Sebastiani & Sons, Napa, Calif. He conducts blind tastings of his bench-top trials for use in programs that retail for $15 and under—a tier that he considers to be “the sweet spot for alternatives.”

“We do a lot of trials every year where we sit down and use new ones: staves, chips, cubes,” he says. Kitchens sinks samples into 1-gallon jugs in proportions similar to what he’d add to a tank. He runs tests using two formats: light-bodied white wine and light-bodied Pinot Noirs. His goal is to have as neutral a control wine as possible.

Preference for staves
A fruity, neutral, medium-bodied Chardonnay and a fruity, neutral, medium-bodied light red wine are what Don LaBorde, assistant winemaker at Francis Ford Coppola Winery, Geyserville, Calif., uses for his bench-top trials. According to WinesVinesDATA, Francis Ford Coppola Winery produces 1 million cases annually.

French oak staves are LaBorde’s barrel alternative of choice. His crew racks wine onto them immediately after pressing. After malolactic and an SO2 addition, the wine undergoes micro-oxygenation in tanks with volumes ranging from 3,000 to 30,000 gallons.

Though he tends to gravitate toward medium-plus toasted French oak, LaBorde still conducts trials in various bracketed toast levels. H e arranges samples from different oak suppliers in families, grouped by their toasting method: infrared, fire and convection toasting. “Like acid trials and blends, we taste blind, no matter what.”

Barrel alternative trials are conducted once or twice per year, when LaBorde does five to 10 flights of six different wines in 750ml bottles. The top three or four are tested in 15-gallon kegs and then stepped up to larger 3,000- to 6,000-gallons tanks.

LaBorde noted that every oak supplier has different recommendations about how much to dose the trials and for how long. There is no standard way to measure oak impact. “The impact is way higher in the trial, but at least the true characters come through. Everything is amplified in the bench trial.” That includes flaws, so the process helps narrow the candidates.

“We rarely want the bench trial impact in our wines. Every company has different calculations. Over time we get our own feel for how much oak to use on a particular wine, so we’ve come up with our own calculator. We start out with the recommended dose and then tweak as we go along. There is some trial and error.”

The tanks are tasted every week and assessed by LaBorde so the alternatives can be pulled if they’re not working. If caught early, there’s still the option to correct any undesirable issues that arise. “Our oak impact is mild, and we like the fruit to come through.”

For those who prefer to cut down the tweaking factor, Oak Solutions Group maintains a usage calculator on its website. The calculator measures a suggested dosage rate by volume and desired oak impact for the company’s lineup of barrel alternative products, which can help reduce trial and error.

Maintaining quality
While speaking about the most crucial consideration when selecting an oak product, Steve Peck from J. Lohr hit the log-splitting wedge on the head: “A supplier’s chain of custody and logistical systems must be trustworthy and have an integrated handling system to assure that fresh product is unadulterated when it arrives at the winery.”

A reputable supplier should be able to articulate what handling and testing protocol a chosen alternative went through. Many alternatives have International Organization of Standardization (ISO) certification and some are even Hazard Analysis and Critical Control Point (HACCP) certified. These certifications simply mean that a self-written protocol was adhered to in order to assure good handling practices, establishing a standard level of quality.

Barrel alternatives from Xtra Oak, Napa, Calif., are HACCP-certified by Bureau Veritas. The raw materials are tested for 2,4,6-trichloroanisole (TCA) and tribromoanisole (TBA) via independent laboratories. Thorough analysis is also conducted on the packaging, the plant where the product was produced and stored and the containers used for transport.

According to McCord at StaVin, “Every stick of wood is tested before it’s toasted.” StaVin tests for TCA and TBA using Bentonite traps over three days with air circulation in an enclosed shipping container. ETS Laboratories then analyzes the traps for airborne TCA and TBA.

Repeat performance
Sharp attention must be paid to the wood itself. Wood varies from tree to tree and stave to stave, so it’s important to know that the oak products you buy in year two resemble as closely as possible those from the lot you bought in year one.

Burton, owner of Barrel Builders, mentioned the daunting number of variables in the barrel alternative business and how everyone wants a hook to be different. He advises winemakers to see past any potential hype and ask themselves, “If I source from this supplier, will I be able to get this again next year?” For repeatability, there should be assurance from the supplier that the product will come from the same forest, same source, same aging protocol and toasting profile.

Melissa Westerman at Innerstave, Sonoma, Calif., said her company has maintained a relationship with the same suppliers for more than 20 years. Innerstave conducts oak aroma analysis to assure consistency of its five flavor profiles and also does haloanisole testing with each new lot number.

With barrel alternative suppliers paying closer attention to the quality and origin of their products, winemakers also can adopt more focused methods in using them. The medium is moving past the image of being a mask for flaws or deficiencies and stepping out into the light, neatly packaged and ready for exploration.




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