Trials conducted during the 2020 harvest with smoke-exposed winegrapes utilizing managed ozone (O3) therapies in transport containers point out such pre-crush therapies can mitigate and cut back ranges of smoke-related risky phenol (VP) compounds from grapes and produce ensuing wines with extra favorable sensory and high quality traits.
Purfresh Wine of Hayward, California (previously branded as Purfresh Clean) provides transport containers in 20-foot and 40-foot sizes outfitted with add-on programs that present temperature management and managed ozone dosing throughout the enclosed container. During the 2020 harvest Purfresh delivered and setup containers for cooperative trials to Napa County wineries Quintessa Vineyards, Hall Wines and Porter Family Vineyards; to Sonoma County wineries Benziger Vineyards and Towle Wine Company; and to Shea Wine Cellars in Oregon.
Purfresh Background and Process
Purfresh Wine CEO Christian DeBlasio mentioned the usage of ozone with recent fruit has been developed and researched over the previous 15 years to protect freshness throughout transport and storage and to increase product shelf-life. In addition, ozone has proven to offer different advantages on totally different fruits by killing mildew and undesirable microorganisms and by the elimination or discount of pesticides and fungicides. Based on ozonation expertise with desk grapes over 5 years to scale back pesticides and protect freshness, Purfresh expanded into treating winegrapes and found ozone can doubtlessly mitigate impacts from wildfire smoke publicity. According to Purfresh, “At particular concentrations ozone can delicately permeate the pores and skin of the grape or different fruit, react with and cut back risky compounds attributable to smoke.”
Based on present information, Purfresh Wine promotes the next potential advantages of its system with winegrapes: elimination of sulfur, pesticides and fungicides pre-crush; decreased sulfur dioxide (SO2) wants post-crush; discount of undesirable microbial organisms and molds from the sphere together with Brettanomyces; prevention of caught and sluggish fermentations; enhanced tannins, anthocyanins and stilbenes for wine high quality; improved wine sensory attributes; and elimination or discount of smoke taint compounds pre-crush.
DeBlasio mentioned most wineries have used the 40-foot measurement “Purfresh Titan Containers.” The 20-foot measurement could also be higher for services with extra restricted crush pad area. On common, a 40-foot container can course of about 22 tons of grapes per day when full, though processing volumes have ranged from 5 to 26 tons per container per day.
Harvested grapes are positioned in half-ton plastic “MacroBins” which have slots within the sides and bottoms, which are then stacked contained in the container. The ozonation course of makes use of a chimney impact, with on-demand ozone technology that feeds ozone fuel with excessive airflow into the underside of the container that permeates via the stack of bins in a managed quantity. Generally, a price of 1 ppm ozone for a 24-hour therapy cycle supplies good outcomes. Purfresh assists customers with establishing the system, and based mostly on expertise, can alter software charges to particular person prospects based mostly on grape selection and different components. DeBlasio cautioned that utilizing the right ozone price and sustaining the identical price is crucial. “If you apply too little, it does nothing, and for those who apply an excessive amount of it might probably trigger undesirable harm to the fruit,” he mentioned.
Based on the 2020 West Coast vineyard trials, DeBlasio mentioned, “All the wineries, based mostly on style profiles and sensory analysis, most well-liked the handled heaps over the untreated heaps, at totally different wine processing stages–in barrel, at mixing and at bottling.”
Although among the wineries did lab testing for smoke compounds to check handled vs. untreated grapes, and to check VP ranges earlier than and after therapies, some reported that analytical knowledge was variable and inconclusive. Lab evaluation of samples taken earlier than and after therapies generally confirmed decreased ranges of guaiacol and 4-methylguaiacol, though the quantity of discount was extremely variable.
Towle Wine Company Trials
Towle Wine Company in Glen Ellen processed a complete of 146 tons of smoke-exposed Napa Valley Cabernet Sauvignon utilizing two, 40-foot Purfresh containers with grapes picked the second week in October 2020. Winemaker Joe Uhr, who makes wines on the facility for the Abbot’s Passage model and for customized crush shoppers, mentioned these grapes have been positioned in half-ton plastic bins with slots and processed following Purfresh suggestions for a 24-hour cycle with as much as 20 tons per container at a time.
Uhr mentioned comparability trials weren’t finished below well-controlled experimental parameters, however he believes the therapies offered advantages, and sure work higher when grapes have decrease ranges of smoke publicity. In sensory evaluations of ensuing wines finished by inner vineyard personnel along with exterior evaluators, the handled wines have been most well-liked over the untreated wines. The wines have been produced for a customized crush shopper and might be used for the identical markets and worth factors as previous vintages.
Uhr mentioned, “This was my first go-round with this course of, so it was a studying course of in a tough yr to completely discern what was occurring. However, I can not argue with the outcomes, and I’d use it once more.” Uhr believes ozonation may additionally present advantages for non-smoke impacted grapes as a device for fermentation normally to deal with risky acidity (VA) points, and remove undesirable microflora for winemakers that desire a extra pure impact from inoculation with added yeast strains. The containers can even present clear storage and refrigeration of grapes for an prolonged time interval if the vineyard doesn’t have capability to crush and ferment masses quickly after supply.
Shea Wine Cellars Trials
Shea Wine Cellars in Newburg, Oregon had vineyards uncovered to about 10 days of low hanging thick smoke from Willamette Valley wildfires prior to reap in 2020 in keeping with winemaker Dana Booth. After harvest started, a Purfresh container was introduced in and used to deal with 50 tons of the vineyard’s property Pinot Noir, whereas one other 50 tons picked beforehand went untreated. Although Booth mentioned he didn’t initially discover important variations between the handled and untreated wines proper after fermentation, he mentioned after post-malolactic fermentation (MLF) in January and February there was a noticeable distinction between the wines. “The handled wines in barrel have been more energizing and extra fruit ahead, they usually had a lesser diploma of smoky notes than the untreated wines,” Booth mentioned.
Booth mentioned the Pinot Noir from this winery historically has a very good phenolic profile and this was higher expressed within the handled wines. The untreated wines have been offered on the majority market. The handled wines are nonetheless within the cellar, and will undergo some further mitigation processing, reminiscent of reverse osmosis (RO). But Booth mentioned the handled wines are on monitor to enter the vineyard’s property mix that’s bottled and offered for every classic.
Booth mentioned, “I’m pleasantly stunned how the wines have responded to the therapies and the way effectively they’re displaying given the diploma of smoke publicity.” He summarized, “As a winemaker, I’d personally use the expertise once more if wanted. I believe there are a selection of variables we may have addressed to enhance and fine-tune the method to enhance outcomes sooner or later, however I believe it is a very promising expertise.”
Molecules Research Paper
Purfresh cites a number of analysis research relating to the advantages of ozone to deal with winegrapes. A latest analysis examine carried out on smoke-exposed Merlot grapes in Australia in the course of the 2019/20 rising season utilizing ozone utilized in managed chilly room situations by researchers from Australian and Italian establishments, together with the Australian Wine Research Institute (AWRI), was revealed in March 2021. The analysis paper, “Potential Mitigation of Smoke Taint in Wines by Post-Harvest Ozone Treatment of Grapes,” was revealed in Molecules, Issue 26, 1798, a world peer-reviewed, open entry journal of chemistry. The harvested grapes have been handled with 1 or 3 ppm of gaseous ozone for 24 hours, or 12 hours previous to winemaking utilizing related therapy strategies to the Purfresh Wine system.
Under “Conclusions” within the Molecules paper, the researchers said: “This examine demonstrated the potential for post-harvest O3 therapy for use to mitigate the depth of taint perceived in wine produced from smoke-affected grapes. Differences have been noticed between the focus of risky phenols (VPs) (in each free and glycoconjugate kinds) in smoke-affected grapes with and with out O3 therapy. At decrease dose charges (i.e., at 1 ppm) ozonation gave considerably decrease VP glycoside concentrations, which resuted in a perceivable enchancment in wine sensory properties, i.e. much less obvious smoky, medicinal, burnt rubber and ashy characters. The O3 dose price might, nonetheless, affect the efficacy of therapy, such that increased doses induce mobile protection mechanisms to oxidative stress that negate or hinder any mitigation of smoke taint.
“Furthermore, the timing of O3 therapy after grapevine smoke publicity could also be necessary, with outcomes suggesting free VPs are extra prone to the results of O3 (presumably oxidation) than their glycosylated kinds. Further analysis is required to optimize the timing, dose price and period of O3 therapy of smoke-affected grapes, and to completely perceive each the chemical and biochemical penalties of ozonation (together with any potential affect on wine coloration and mouthfeel properties as a result of results of O3 on biosynthesis of phenolic compounds). However, collectively, the outcomes offered right here exhibit the efficacy of post-harvest ozone therapy as a promising new technique for mitigation of smoke taint in wine.”
Purfresh Wine can provide, ship and set-up containers for therapies at wineries for the 2021 harvest. New choices for 2021 embody 4 various kinds of bins, obtainable via a lease association with the bin provider, based mostly on the grape selection and the vineyard’s wants. More data is out there at www.purfresh.com