Automated Measurement and Interpretation of Wine Filterability

¹ Stonestreet Winery, 7111 Highway 128, Healdsburg, CA 95448
² Department of Viticulture and Enology, University of California, One Shields Ave., Davis, CA 95616, USA.

email: rbboulton{at}ucdavis.edu

An automated system for the collection of filtration test data has been developed and tested with the membrane filtration of wines. An in-line filter holder with a venting valve contains the membrane filter. A personal computer controls a solenoid valve that starts and stops the wine flow and acquires data from an electronic balance every few seconds. The balance is tared with an empty collection beaker prior to the test, and the wine is dispensed from a pressurized canister. The weight of the wine filtered is recorded at intermittent times. The data can be analyzed using previously developed models for the fouling of filters or one of several empirical fouling indices. The system was used for filtration measurement in 66 wines of various ages and types. The various fouling indices, the wine-dependent parameters calculated from the filtration models, and the levels of unstable colloids were compared using principal component analysis. The wine-related constant of the exponential model was well correlated with the least soluble colloid content, but these were poorly correlated with all of the empirical fouling indices and the maximum volume of filtrate.

Note:
Acknowledgments: The authors gratefully acknowledge the technical assistance of Michael J. Delwiche, Biological and Agricultural Engineering, Bill Weigt, Engineering Electronic Group and Ernie Farinias, Department of Viticulture and Enology, at the University of California, Davis.

Key words: Wine filtration, membrane filtration, microfiltration, colloid content, fouling indices, measurement system