Grape juice for white wine is

winemaking FILTRATION Filtration of grape juice sediments: a new application for cross-flow s By Patrik Schonenberger 1, Davide De Giorgi 1 and Julien Ducruet 1,2 1 Engineering School of Enology in Changins, Route de Duillier 50, Case postale 1148, 1260 NYON 1, Switzerland 2 Corresponding author: Dr Julien Ducruet. Email: julien.ducruet@eichangins.ch Introduction Grape juice for white wine is usually pre-clarified to a certain degree before undergoing alcoholic fermentation. Traditionally, this pre-clarification has been done by allowing particles to settle overnight and racking off the clear juice. The settled particles (sediments) are ed with a press or a rotary vacuum to obtain higher yields of clear juice. These techniques have proved to be efficient, but contain inconveniences, such as the removal of filtration residues (including adjuvants like diatomaceous earth, perlite, etc.) which may pose environmental concerns (Montigaud 2010, Desenne 2004). Other important concerns in wineries are the initial dilution of the juice, little versatility, and labour hours for the cleaning procedure. Rotary vacuum s have been studied extensively over the last 40 years. Some of the main consequences found for the ed juices are linked to the use of the vacuum itself: decrease of carbon dioxide concentration and free sulfur dioxide levels, losses of some desired volatile compounds (e.g., primary aromas), and increased risk for juice oxidation (Riberau-Gayon et al. 1998). The first cross-flow s used in the wine industry were reported to have heavy impacts on the ed wines. Such wines reached lower scores than wines made from rotary vacuum-ed juices, as evaluated by professional tasting panels (Serrano and Paezold 1998). In recent studies with updated technology and improved membrane characteristics, no differences were found between wines from cross-flow ed and rotary vacuum-ed juices (Etienne and Benestau 2000, Cuénat et al. 2003). However, Vernhet et al. (1998) analysed wine components in the laboratory and reported lower levels of colloidal compounds in wines from cross-flow ed juices compared with wines from rotary vacuum-ed juices. Cuénat et al. (2003) noted in a study that ceramic Figure 1. Cross-flow FX 3 (Bucher-Vaslin SA, France), equipped with an adapted module and the corresponding computer software, which allows the filtration of very dense and viscous juice sediments. membranes retained more colloids than membranes made with polysulfone. Cross-flow s with adapted modules for the filtration of dense sediments appeared on the market only recently. This new application for cross-flow s offers the possibility to wines, juices, and juice sediments with one device. The present study was carried out as part of a Bachelor of Sciences thesis (De Giorgi 2010) at the School of Enology in Changins, Switzerland, to evaluate the impact of this new application on the quality and composition of the final wines. Crossflow filtration of juice sediments was compared with the standard filtration with a rotary vacuum. Materials and methods Two experiments were carried out with two pre-clarification methods (gravitational settling and flotation). After pre-clarification, sediments were ed with a rotary vacuum and compared with the filtration from a cross-flow. Filter technology A cross-flow FX 3 (Bucher Vaslin SA, France) was equipped with an adapted module and the corresponding computer software, which allows the filtration of very dense and viscous juice sediments. The membrane was made of polyether 28 www.winebiz.com.au Wine & Viticulture Journal MARCH/APRIL 2012 V27N2

FILTRATION winemaking sulfone with spaghetti -type capillaries (internal capillary diameter 3mm). The filtration surface was 18m 2 with 0.2µm pore size. Water (cold and hot) and compressed air were connected permanently for proper running of the. The computer software controlled all valve openings (wine, water and air) and supervised filtration, rinsing, and cleaning programming (Figure 1). A rotary vacuum (VELO, Italy) with an integrated vacuum pump and a filtration surface of 8m 2 was used as the standard procedure. Filtration media was Seitz Perlite A (Pall SeitzSchenk Filter Systems GmbH, Germany). Grape juice White Chasselas (Vitis vinifera L. cv Chasselas) juice from a commercial vineyard (Château d Auvernier, Switzerland) was used. Enzymes (10mg/L Depectil Clarification FCE, Martin Vialatte) and SO 2 (80mg/L) were added to the juice before the application of the treatments. The fraction of the juice that was floated before filtration received 200mg/L gelatin (provgreen Extra, Martin Vialatte) prior to flotation, in addition to the enzymes and the SO 2. No other product was added to the juice. One fraction of the juice was pre-clarified overnight by gravitational settling at ambient temperature (16 C). A second fraction was preclarified by flotation, using a Turboflot ECO 5000 (Kunzmann and Hartmann, Germany) with an average flow rate of 7500L/h. Flotation gas was nitrogen. The sediments of both pre-clarification methods were then ed using both cross-flow and rotary vacuum filtration. Inherent to rotary vacuum filtration, the first fraction of the juice was diluted and not used for the winemaking. Winemaking Special care was taken to use only juice fractions with the same sugar levels (total soluble solids) before and after filtration. After filtration, wines were replicated three times in stainless steel tanks (each containing 200L of juice). Standard procedures for white Chasselas wine production in Switzerland were applied, and attempts were made to keep the temperatures identical in all tanks, i.e., alcoholic fermentation at 18 C and malolactic fermentation at 16 C. For the alcoholic fermentation, all tanks were inoculated separately with 0.2g/L Vitilevure Quartz (Saccharomyces cerevisiae galactose, Station Oenotechnique de Champagne, France). For the malolactic fermentation, 0.01g/L Vitilactic F (Martin Vialatte, France) was added to the wines. SO 2 at a rate of 50mg/L was added after malolactic fermentation, and the wines were then stored at 2 C for a period of six weeks for physical stabilisation. Wines were pre-ed with AF100 pads (Filtrox AG, Switzerland) and, before bottling, were sterile ed with AF130 pads (Filtrox AG, Switzerland). Chemical analysis The sugar content of the juice was measured with a standard refractometer. Alcohol content, titratable acidity, tartaric acid, malic acid, lactic acid, and volatile acidity were analysed with a WineScan TM (FOSS Analytical, Hilleroed, Denmark) which uses Fourier Transform Infrared (FTIR) Spectroscopy. The FTIR analysis was carried out with the clear fraction of the juice after centrifuging the samples for 10 minutes at 5000rpm. Samples were also centrifuged for calculating the proportion of dry matter in the total Winemakers bottling for winemakers With ten winemakers working across six sites, Portavin is close to market and transport hubs, saving time, money and the environment. Portavin caring for your wine from tank to shelf Adelaide Auckland Margaret River Melbourne Perth Sydney (08) 8447 7555 (09) 582 0090 (08) 9755 0500 (03) 9584 7344 (08) 9437 1033 (02) 9722 9400 www.portavin.com.au portavin@portavin.com.au V27N2 Wine & Viticulture Journal MARCH/APRIL 2012 www.winebiz.com.au 29

winemaking FILTRATION Table 1. Chemical analyses of the initial juice after pre-clarification by gravitational settling and flotation. Juice analysis total soluble solids (Brix) Titratable acidity ph Dry matter (% of total volume) After gravitational settling 19.1 7.10 3.29 8.78 After flotation 19.1 7.30 3.22 28.25 volume. The volume of the centrifuge deposit was divided by the initial total volume to obtain the percentage of dry matter. Statistical analysis Data were subjected to the analysis of variance (ANOVA) and F-test. The coefficient of variation (CV) was calculated to obtain the relative percentage of the standard deviation (Excel 2007, Microsoft, Redmond, WA). Sensory evaluation The bottled wines were stored for three months before being exposed to sensory evaluation by an expert panel. Two panels of 24 and 16 judges, respectively, were present at two tasting sessions. Quantitative Descriptor Analysis profile (QDA ) with 10 different terms was employed to describe the wines. Results and discussion Chemical analyses of the initial juices are shown in Table 1 (total soluble solids, titratable acidity, ph, and dry matter as a percentage of the total volume). The two types of sediments obtained by flotation and gravitational settling were distinctly different: sediments from flotation were denser and more viscous than sediments from gravitational settling (28.25% versus 8.78% dry matter of total volume, Table 1). Both filtration techniques cleared the juice to a very low but comparable level of suspended material (<1.00% dry matter of total volume, data not shown). A temperature rise of 6 C was observed in the juice during cross-flow filtration (data not shown) and needs some consideration. Similar differences for input and output temperatures for cross-flow ed wines have been reported previously in comparative studies (Ducruet et al. 2006). Cross-flow filtration may negatively affect a juice with a higher input temperature. It is preferable to conduct the filtration with an initial juice temperature below 16 C to reach a maximum temperature of 22 C at the output side of the. The chemical analyses of the finished wines showed no significant differences for alcohol content, acidity levels, and volatile acidity (Tables 2 and 3). Significantly lower absorbance at 280nm was observed in wines made from rotary vacuum-ed juices compared with those from cross-flow ed juices (Tables 2 and 3). The absorbance at 280nm is an indication for total polyphenols in the juice. If rotary vacuum filtration caused more polyphenol oxidation than crossflow filtration (Riberau-Gayon et al. 1998), one portion of these oxidised Filtration & Purification Specialists For all of your winery and beverage processing needs. Premium quality filtration solutions and specialists you can trust. Complete filtration solutions from water to wine Premium BECO sheets & lenticular modules Turnkey filtration systems Australia s largest range of housings SIHA biotechnology & wine additives HO 2 CALL FOR MORE INFORMATION Blue H2O Filtration Pty Ltd 29 Dalgety Street Oakleigh VIC 3166 Ph +61 3 9564 7029 Fax +61 3 9564 7039 info@blueh2o.com.au www.blueh2o.com.au 30 www.winebiz.com.au Wine & Viticulture Journal MARCH/APRIL 2012 V27N2

FILTRATION winemaking Table 2. Chemical analyses of the final wines made from juice obtained by gravitational settling. Juice was ed, vinified, stabilised, and stored for three months in the bottle. Wine analysis Alcohol (% volume) Tartatic acid Malic acid Lactic acid Acetic acid Volatile acidity Absorbance (280 nm) Chromtic intensity (absorbance 420 nm) Juice obtained by gravitational settling Rotary vacuum 10.9 1.73 0.41 1.94 0.23 0.42 5.267 0.143 Cross-flow 11.1 1.70 0.47 2.25 0.18 0.42 6.000 0.154 significance ns ns ns ns ns ns ** ns CV % 3.05 3.62 4.45 3.77 21.25 3.09 2.33 19.24 *, **, ***, ns: Main effects significant at P < 0.05, P < 0.01, P < 0.001, or not significant, respectively. Table 3. Chemical analyses of the final wines made from juice obtained by flotation. Juice was ed, vinified, stabilised, and stored for three months in the bottle. Wine analysis Alcohol (% volume) Tartaric acid Malic acid Lactic acid Acetic acid Volatile acidity Absorbance (280 nm) Chromatic intensity (absorbance 420 nm) Juice obtained by flotation Rotary vacuum 11.3 1.67 0.48 2.05 0.28 0.47 5.650 0.223 Cross-flow 11.2 1.65 0.51 2.18 0.13 0.43 6.310 0.126 Significance ns ns ns ns ** ns * * CV % 0.04 0.04 0.22 4.73 18.62 8.51 7.52 45.77 *, **, ***, ns: Main effects significant at P < 0.05, P < 0.01, P < 0.001, or not significant, respectively. FILCHEM A Complete Range of Filter Media Ertel Alsop lenticular cartridges & sheets Graver membrane cartridges Celite DE Harborlite Perlite Diacel cellulose Activated Carbon Filchem Australia Pty. Ltd 1 800 33 1125 Fast and ACCURATE results for wine analysis with the Thermo range of Gallery and Arena Discrete Analysers Compact design occupies a small footprint and is fully self-contained. Flexible loading capacity up to 45 samples or 30 reagents simultaneously. All necessary steps are automated, providing a walk-away time up to two hours. For more information on this product, contact us by email at sales. daniel.hoger@thermofisher.com www.thermofisher.com.au 1800 333 110 Moving science forward Thermo Scientific Gallery Photometric Analyzer V27N2 Wine & Viticulture Journal MARCH/APRIL 2012 www.winebiz.com.au 31

winemaking FILTRATION Figure 2. Quantitative Descriptor Analysis profile (QDA ) of the final wines made with juice obtained by gravitational settling (*, **, ***: Main effects significant at P < 0.05, P < 0.01, P < 0.001). polyphenols might have flocculated and immediately ed out of the juice, which did lower total polyphenols in rotary vacuum-ed juices. The portion of the remaining oxidised polyphenols (indicated by chromatic intensity) was not different in both filtration techniques, if the juice was MaloBacti MLF MAXIMUM SECURITY MALO s The only strains on the market with a ph test that confirms viability of active bacteria prior to inoculation! MaloBacti CN1 Citric negative MLF MaloBacti HF2 Colour protection & flavour management MaloBacti AF3 Elevated phenolics & high alcohol MAXBacti New large volume concept MaloControl Complete MLF supplement obtained by gravitational settling (Table 2). On the other hand, if the juice was obtained by flotation, the portion of the oxidised polyphenols (indicated by chromatic intensity) and acetic acids were increased in rotary vacuumed juices (Table 3). However, a high CV of 18.62% and 33.3%, respectively, suggested that other factors than the application of the treatments may have influenced these data (Table 3). The QDA profiles of the tasting panels showed few differences in the final wines (Figures 2 and 3). Cross-flow filtration of juice sediments produced wines with less intense odours and more pronounced acidity levels compared with wines from rotary vacuum-ed juice sediments. Conclusion Cross-flow s offer several possibilities to facilitate cellar work. They produce less filtration residues and may free labour hours through automation during intense harvest time. Cross-flow s are more versatile than rotary vacuum s; one may be used for wine, juice, and juice sediment filtration. However, initial investments are more substantial for a cross-flow. Some products (e.g., bentonite, activated charcoal) may not be added to the juice before cross-flow filtration, Innovation. in order to prevent the membrane from plugging. These experiments were carried out with Performance. one grape variety and one vintage. Proximity. Better equipment Delta Fruit receival is the key to success Flavy Cross flow filtration Our dealership network Australia and New Zealand South Australia and New South Wales and Western Australia: Queensland: SWAT Trading Wine Energy Tel: 08 9755 5766 Tel: 0407 400 728 Bucher Vaslin Australia Victoria and Tasmania: New Zealand: Vinvicta Products Viniquip International: Tel: 03 9464 7414 Tel: +64 9578 3740 Bucher Presses Flavy Cross flow filtration Our dealership network Australia and New Zealand SALES NZ SALES VIC/TAS/ACT SALES & SERVICE WA Viniquip Vinvicta SWAT trading Horst Klos Steve Jenkinson Rob Menzies Tel: (06) 879 7799 T: 1300 360 353 T: (08) 9755 5766 SALES SA SERVICE & PARTS SERVICE & PARTS Filters SA APV Australia APV New Zealand T: (08) 8388 3999 Les Jarvis Grant Dewson T: 1800 100 278 T: 800 500 278 Po Box 1051, Glen Waverley, 3150, tel 1300 Bucher National Sales Manager: Peter Keeghan tel. 0417 816 024 Email: peter.keeghan@buchervaslin.com For further information, please contact Kauri NZ Ltd. NZ Tel: 0800 KAURIWINE AUS Tel: 1800 127 611 NZ Fax: 04 910 7415 AUS Fax: 1800 127 609 Email: winery@kauri.co.nz Web: www.kauriwine.com Bucher Vaslin Australia Pty Ltd PO Box 1051, Glen Waverley, 3150 Samuel Plumejeau Tel: 0427 655 800 www.buchervaslin.com Your See success us at is our Winetech priority July 29th to August 1st in Adelaide 32 www.buchervaslin.com www.winebiz.com.au Wine & Viticulture Journal MARCH/APRIL 2012 Your success is our priority V27N2

FILTRATION winemaking Further studies need to be done to better understand the behaviour of the juices and finished wines over time after using cross-flow technology. Acknowledgements The project was conducted as part of Davide De Georgi s Bachelor of Science thesis, which was supervised by Dr Julien Ducruet. We greatly appreciated the technical assistance of M. Droz Frédérique (Château d Auvernier, Switzerland) and M. Erik Dobrovolski (Bucher Vaslin SA, France). References Cuénat, P.; Lorenzini, F. and Bregy, C.A. (2003) Comparaison de membranes en céramique et polysulfone pour la microfiltration tangentielle des vins. Revue Suisse de Viticulture, Arboriculture, Horticulture 35(6):110-119. DeGiorgi, D. (2010) Etude de la filtration tangentielle des bourbes comparée aux techniques existantes. BS Thesis, Engineering School of Enology in Changins, Switzerland. Desenne, A. (2004) Les filtrations: une pollution différente selon le typ de filtre. Chambre d agriculture de la Gironde service vigne et vin. http://www.matevi-france.com/welcome_menu. asp?tp=choix_experimentation [accessed 10/02/2010] Ducruet, J.; Silvestri, A.-C. and Hyppenmeyer, P. (2006) Etude comparative de différents filtres Figure 3. Quantitative Descriptor Analysis profile (QDA ) of the final wines made with juice obtained by flotation (*, **, ***: Main effects significant at P < 0.05, P < 0.01, P < 0.001). tangentiels en œnologie. Revue Suisse de Viticulture, Arboriculture, Horticulture 38(5):297-302. Etienne, F. and Benestau, F. (2000) Filtration tangentielle: impact sur la qualité des vins. Revue des Œnologues 27(96):13-15. Montigaud, I. (2010) Les terres de filtration pourraient finir en compost. Réussir Vigne. N 164: 35. Riberau-Gayon, P.; Glories, Y.; Maujan, A. and Dubourdieu, D. (1998) La clarification des vins par filtration et centrifugation. Traité d œnologie. Vol 2. Chimie du vin stabilisation et traitements. Edition Dunod: 383-427. Serrano, M. and Paetzold, M. (1998) Incidence des filtrations sur la composition chimique et les qualités organoleptiques des vins. Journal International des sciences de la vigne et du vin. Traitements physiques des moûts et des vins. Filtration. N hors série. pp 53-57. Vernet, A.; Moutounet, M. and Escudier, J-L. (1998) Microfiltration tangentielle des vins. Journal international des sciences de la vigne et du vin. Traitements physiques des moûts et des vins. Filtration. N hors série 45-52. WVJ WINE BARREL RACKS Flexibility for stacking, handling and transport of wine barrels Conventional or Barrel Master Proudly designed and manufactured by JOHN FALLAND AUSTRALIA Setting Standards Since 1961 Moppa Road South, Nuriootpa, SA 5355 Ph: (08) 8562 1533 Fax: (08) 8562 2103 Email: john@jfallandaust.com.au Website: www.jfallandaust.com.au New Zealand sales and distribution: KAURI NEW ZEALAND LIMITED Ph: 04 476 0105 Fax: 04 476 0161 PO Box 17-385,. Karori, Wellington. Fabricated 20 years ago and still popular Over 270,000 made for over 1200 wineries Stack five high with your forklift Lifetime galvanized finish Competitive prices Reg Design No 117931 Superior rack on rack stack system Simple, uncluttered design Visible & easy rack locating system No weight on barrels Static or barrel rolling options Reg Design No 154262 V27N2 Wine & Viticulture Journal MARCH/APRIL 2012 www.winebiz.com.au 33