Transcript Formal Method Prefermentation Nutritional

Filtration Difficulties
Molly Kelly
Virginia Tech Enology Extension
Wineries and Breweries Unlimited
March 13,2014
Overview
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Factors
Types
Deformable vs Non-deformable particles
Integrity testing
Filter?
Other
Why Filter?
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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
Factors impacting filterability
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Variety
Rot
Fruit type
Season
Processing
– Enzymes
– Fining/residual fining agents
– Yeasts/bacteria
Types of filtration
Depth filtration
– Wine moves through tortuous path
Gusmer Inc.
– 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
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
Types of filtration
Absolute filtration
– Membrane filtration
– Filtration occurs at the surface
Gusmer
– Standard sized pores;99%+ reliability
– Trap all particles larger than pore size
– Clog easily
– 0.45 micron, “sterile”; sequential depth plus
absolute filtration
Inc.
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
Deformable vs. Non-deformable
particles
• Non-deformable: retain shape
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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
Deformable vs Non-deformable
Gusmer Enterprises, Inc.
<0.2 microns-1000 microns
Colloids
• Protein fractions: mw 20-40 Kda
• Polysaccharide fractions: mw 10-500 Kda
– Grapes
– Yeast
– Botrytis cinerea
• Marginally soluble fractions
– Form fine dispersed aggregates in solution
– Deposits on surfaces
– Membrane filter fouling
Botrytis
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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
Stemstore.tumblr.com
Beta-glucan
Villettaz et al. 1984
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
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
Polysaccharides
Polysaccharides may derive from the plant
or from microbial activity
www.wynboer.com
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
Glucans
• Result of Botrytis growth on grapes
• Result of spoilage LAB
• Gel formation with acidified ethanol
– (Zoecklein et al., 2005)
Laffort.com
Starch
• Can cause haze in apple juice and cider
• Affects clarity and filtration
• Test for starch haze (Zoecklein et al.
2005)
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
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
Bubble point
Millipore inc.
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
Filter sheets
• Ruptured sheets: major source backpressure shock
– Rapid valve closing, shutting off/pulsation of
pump
Winesand vines.com
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
Colloidal macromolecules
• May be present as large aggregates of
polysaccharides, mannoprotein or proteinphenolic 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
Mouthfeel
• Colloids-viscosity
• May have tannins and anthocyanins
attached
• Does filtration (0.45 micron) remove
significant amount of colloids?
• No conclusive evidence
• Possible?
Aging
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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
Ezramagazine.com
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
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
References
• Zoecklein, B. Filtration. Wine/Enology and grape Chemistry Group,
Virginia Tech. 2014.
• Mansfield, A.K. Cellar Dweller. Cornell Extension Enology Lab,
February 2010. Accessed Feb 29.
www.grapesandwine.cals.cornell.edu/extension.
• Bisson, L. Post Fermentation Processing. Accessed Feb 20 2014.
http://lfbisson.ucdavis.edu/PDF/VEN124%20Section%205.pdf
• Butzke, C. Winemkaing Problems Solved. Woodhead Publishing,
Oxford. 2010.
• Reynolds, A. Managing Wine Quality. Woodhead Publishing,
Oxford. 2010.
• Alarcon-Mendez and R. Boulton. 2001. Automated measurement
and interpretation of wine filterability. Am. J. Enol. Vitic. 52:3.
• Villettaz, J.C. et al. 1984. 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.
Questions?
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