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Filtration Difficulties

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Presentation on theme: "Filtration Difficulties"— Presentation transcript:

1 Filtration Difficulties
Molly Kelly Virginia Tech Enology Extension Wineries and Breweries Unlimited March 13,2014

2 Overview Factors Types Deformable vs Non-deformable particles
Integrity testing Filter? Other

3 Why Filter? Remove particulates Remove fining agents Remove colloids
Remove yeast and bacteria All of these particles are easily deformed so excess pressure can cause coating that retards filtration

4 Factors impacting filterability
Variety Rot Fruit type Season Processing Enzymes Fining/residual fining agents Yeasts/bacteria

5 Types of filtration Depth filtration Wine moves through tortuous path
Filtration occurs on surface AND interior matrix Rated with nominal or normal porosity Some % (70-98%) of particles of that size will be retained Use specified flow rates Ex: DE, plate and frame filters, disc filters Gusmer Inc.

6 Disadvantages of Depth filtration
Media migration Increases with surge vs uniform flow Microbial growth within filter matrix Contamination of filtrate Some product can remain in filter matrix “Sterile” pads?; cannot validate porosity

7 Types of filtration Absolute filtration Membrane filtration
Filtration occurs at the surface Standard sized pores;99%+ reliability Trap all particles larger than pore size Clog easily 0.45 micron, “sterile”; sequential depth plus absolute filtration Gusmer Inc.

8 Disadvantages of Absolute filtration
Low “dirt handling”capacity Use only with “clean”wines to remove microorganisms Not all particles with diameters less than pore size flow through May be retained in pore passage, blocking flow Do not wait >48 hours after prefilter

9 Deformable vs. Non-deformable particles
Non-deformable: retain shape Diatoms or diatomaceous earth: various grades Rigid nature: act as filtration medium Tartrate crystals Shape will not change with applied pressure Deformable-majority of wine/juice particles Yeast, bacteria, colloids (including fining agents ex: gelatin), protein/phenol/polysaccharide complexes Elastic nature-spread over surface area; block filtrations Proactive: rack, fine, enzymes

10 Deformable vs Non-deformable
Gusmer Enterprises, Inc. <0.2 microns-1000 microns

11 Colloids Protein fractions: mw 20-40 Kda
Polysaccharide fractions: mw Kda Grapes Yeast Botrytis cinerea Marginally soluble fractions Form fine dispersed aggregates in solution Deposits on surfaces Membrane filter fouling

12 Botrytis Beta-glucan insoluble in 30% ethanol (v/v)
Filament like precipitate Specific detection for this polysaccharide Prevents natural sedimentation of particles (like pectin) Alcohol acts as aggregation factor; polymerization Most severe at end of fermentation Beta-glucanase

13 Beta-glucan Villettaz et al. 1984

14 Agglomeration Image  by Kathryn Erbe Many suspended particles will adhere to similar particles Result in single larger particle Larger particles may precipitate naturally or by fining Easier to remove by filtration

15 Polysaccharides Includes pectins and glucans Deformable particles
May be colloidal in juice and wine Impede filtration In alcoholic solution, both are unstable Form gelatinous aggregates

16 Polysaccharides Polysaccharides may derive from the plant or from microbial activity

17 Pectins Structural component of plant cell walls
Can impede clarification Test : add pectolytic enzyme and perform precipitation test Proactive enzymatic treatment of must/juice recommended Pectins and glucans high in concentrates

18 Glucans Result of Botrytis growth on grapes Result of spoilage LAB
Gel formation with acidified ethanol (Zoecklein et al., 2005)

19 Starch Can cause haze in apple juice and cider
Affects clarity and filtration Test for starch haze (Zoecklein et al. 2005)

20 Sterile filtration Integrity Testing
Membrane filters must be preceded by 99.9% filtration Must be bubble tested before, during, and after run If fails, product between that time is suspect

21 Bubble point Gas pressure where surface tension of water in filter pores is overcome Gas passes through pores Dependent on pore size Are leaks present anywhere? Means of checking integrity of system

22 Bubble point Millipore inc.

23 Pressure Hold Integrity Test
Monitor upstream pressure decay as gas diffuses through wetted membrane Pressurize housing to 80% bubble point Turn off gas Monitor how quickly upstream pressure drops (<2 psig in 5 min) Precise pressure gauges

24 Filter sheets Ruptured sheets: major source back-pressure shock
Rapid valve closing, shutting off/pulsation of pump Winesand

25 Does filtration change sensory character?
Soluble flavor and aroma compounds are well below 0.45 microns Sensory impact hard to quantify subjective nature of sensory analysis Soluble species are probably not removed by macro and micropore filtration Maybe colloidal macromolecules that impact mouthfeel

26 Colloidal macromolecules
May be present as large aggregates of polysaccharides, mannoprotein or protein-phenolic complexes (500+kd) May play role in wine’s texture/structure Interaction between macromolecules and and low mw volatile compounds may account for aromatic changes after sterile filtration

27 Mouthfeel Colloids-viscosity
May have tannins and anthocyanins attached Does filtration (0.45 micron) remove significant amount of colloids? No conclusive evidence Possible?

28 Aging Phenols bind together and polymerize
Molecular weight and size increases Filtration can remove these Older red wines have more polymerized phenols Greater negative effect from filtration Color reduction

29 Sorbate? Can replace with filtration to 1 micron
Removing yeast, not bacteria Sensory changes due to ethyl sorbate Sorbate and ethanol Candied fruit, Juicy fruit Geranium taint microbial

30 Conclusions No filtration?-can lead to instabilities Sanitation
Follow manufacturers operating directions Flow rate, pressure differential Test wines for filterability Wines with similar turbidity can have different filterability indices (Cattaruzza et al. 1987) Keep good records

31 References Zoecklein, B. Filtration. Wine/Enology and grape Chemistry Group, Virginia Tech Mansfield, A.K. Cellar Dweller. Cornell Extension Enology Lab, February Accessed Feb 29. Bisson, L. Post Fermentation Processing. Accessed Feb Butzke, C. Winemkaing Problems Solved. Woodhead Publishing, Oxford Reynolds, A. Managing Wine Quality. Woodhead Publishing, Oxford Alarcon-Mendez and R. Boulton Automated measurement and interpretation of wine filterability. Am. J. Enol. Vitic. 52:3. Villettaz, J.C. et al The use of a beta glucanase as an enzyme in wine clarification and filtration. Am. J. Enol. Vitic. 35:4. Patterson, T. If filtration strips wine, what’s getting stripped?. Wines and Vines. Oct 2008.

32 Questions?

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