Wine Manufacturing Application Guide
Wine Processing Conditions & Solutions
Pleated cartridges, capsule filters, clarification, prefiltration and final membrane filtration
A process-oriented guide to clarification, prefiltration and final membrane filtration before bottling, including filter-media selection, microbial-risk control, troubleshooting and scale-up for still, sparkling and low-alcohol wines.
01 — 06
Typical wine filtration train before bottling
01Grapes and must→
02Clarification and stabilization→
03Depth prefiltration→
041–3 µm protection stage→
050.45/0.65 µm final membrane→
06Hygienic bottling
precision map
| Precision/grade | Main removal targets | Recommended position |
|---|---|---|
| 50–100 µm | Pomace, coarse lees, large tartaric crystals | Post-pressing, Before Lees Recovery |
| 20–50 µm | Must Solids, Diatomaceous Earth Clumps, Coarse Suspended Matter | Before and After Pressing, During Recovery |
| 10–20 µm | Fine Lees, Partial Crystals, and Aid Filtration | After Coarse Clarification |
| 3–5 µm | Remaining Yeast Clumps, Bentonite Fine Powder, Fine Particles | First Protective Stage Before Final Filtration |
| 1–3 µm | Fine Yeast, Colloidal Aggregates, Final Particles | Protection Before Final Membrane Filtration |
| 0.8–1.2 µm | Yeast and Partial Brett Control, Cautionary Filtration | Before Red Wine or Final Membrane Filtration |
| 0.65 µm | Yeast Control; Partial Wine Can Be Final Stage | Before Bottling |
| 0.45 µm | Common final membrane filtration before bottling; yeast, Brett, and most wine bacteria control | Last stage before bottling machine |
| 0.2/0.22 µm | Stricter bacterial control; low alcohol, sweet wines, additions, or process water | Use after risk assessment |
microbial target
| Target | Condition assessment | Recommended grade | Acceptance |
|---|---|---|---|
| Saccharomyces and general post-fermentation yeast | Residual sugar, low SO2, high bottling temperature | 0.65 µm can be the starting point; high risk select 0.45 µm | Culture before and after filtration; confirm bottling sample |
| Brettanomyces/Dekkera | Red wine, barrel-aged, volatile phenol risk | Public research shows that ≤0.8 µm can retain specific strains; in engineering, prioritize 0.45–0.65 µm and validate. | Brettanomyces-specific cultivation or molecular detection; bioburden reduction for aseptic filling boundary |
| Lactic acid bacteria | MLF not complete, high pH, lysozyme/potassium sorbate system | 0.45 µm validated with wine-related microbial strains; rigorous condition evaluation of 0.2/0.22 µm | Target microorganism challenge, integrity, post-filter cultivation |
| Acetic acid bacteria | oxygen exposure, low alcohol content, equipment contamination | 0.45 µm or higher grade, combining oxygen exclusion and hygiene | aerobic culture, dissolved oxygen, bottling hygiene |
| molds and larger cells | raw material or environmental contamination | upstream clarification can significantly reduce; terminal filtration still selected based on yeast/bacterial targets | Environmental Monitoring and Finished Product Culturing |
pleated filter cartridge, capsule filter, and depth filtration media
| Product | Applicable Scale | Recommended Applications |
|---|---|---|
| PP Pleated Depth Filtration Cartridge | Small Batch to Large Scale Production | 20, 10, 5, 3, 1 µm Protection; High Adsorption Capacity |
| Hydrophilic PES Pleated Membrane Filter Cartridge | Bottling Line | 0.65, 0.45, or 0.2/0.22 µm final filtration |
| PES Capsule Filter | Lab Use, Additives, Sparkling Wine Small Batch, Mobile Lines or One-Time Isolation | 1–3 µm Protection or 0.65/0.45/0.2 µm Final |
| Depth Plate/Lens Module | Small to Large Wineries | High Colloidal Load, Final Membrane Protection, Bioburden Reduction |
| Crossflow Membrane System | Medium to Large Wineries or High Solids Conditions | One-Step Clarification and Significant Load Reduction |
Wine Condition Card: Raw Materials and Fermentation Segment
Condition 01 | Freshly Pressed White Grape Juice, High Turbidity, Pectin Rich
| Project | Recommendation |
|---|---|
| On-site Performance | >100–200 NTU; pomace, skins, and pectins; small filter cores can become clogged in a few minutes. |
| Judgment | This is a solid-liquid separation condition, not a final membrane filtration condition. |
| Route | Settling/Air flotation/Centrifugation → 50–100 µm Sizing → 20–50 µm Coarse Filter; Down to <60 NTU for further assessment of plate and frame or crossflow filtration. |
| Product | Coarse Sizing, Bag or High Capacity Deep Media; Not Recommended to Use 0.45/0.65 µm PES Directly. |
Operating Condition 02 | Botrytized or Moldy Grapes, β-Glucan Leading to 'Clear but Fouled Membrane'
| Project | Recommendation |
|---|---|
| On-site Performance | NTU is not high, but the membrane pressure difference of 0.45 µm rises rapidly; the backwash interval is getting shorter. |
| Judgment | Botrytis glucans, pectins, and their large molecular fragments form a high-viscosity coating layer. |
| Route | Raw material selection → Full clarification → Optional pectinase/β-1,3-1,6 glucanase treatment → 5–10 µm depth filtration → 1–3 µm protection → Final membrane filtration. |
| Product | Use high-capacity depth filtration medium initially; PES membrane only at the end. |
Process condition 03 | Hot maceration of red grape must or hot fermentation
| Project | Recommendation |
|---|---|
| Field performance | High fines, natural enzymes destroyed by heat, slow clarification, low capacity of pleated filter cartridge. |
| Judgment | High fines formed by heat and stirring, release of polysaccharides; high solid content separation. |
| Route | Settling/centrifugation → Tubular or dynamic crossflow/vacuum drum → 5–10 µm depth filtration; clarify the must before proceeding to the final route. |
| Product | Do not treat must or lees directly with conventional 0.45 µm pleated membrane. |
Process condition 04 | End of fermentation, high lees and yeast burden
| Project | Recommendation |
|---|---|
| Field performance | >60 NTU；yeast, tartaric crystals, proteins, and pectins coexist. |
| Determine | Clarify first, then discuss final microbial stability. |
| Process Flow | Transfer/vintage → centrifugation, diatomaceous earth filtration, plate and frame or crossflow → 5–10 µm → 1–3 µm. |
| Product | PP deep pleated or lens modules handle fouling; PES final membrane delayed. |
Operating Condition 05 | post-lees aging with increased mannoproteins
| Project | Recommendations |
|---|---|
| Field Performance | Wine appears clear, fine membrane flow rate decreases; significant variation between tanks. |
| Determine | Yeast autolysis releases polysaccharides, colloidal load cannot be fully reflected by NTU. |
| Process Flow | Small-scale FI/Vmax → 3–5 µm adsorption/deep filtration → 1 µm protection → 0.45/0.65 µm final. |
| Product | Choose low adsorption final membrane; allow deep filtration to carry the colloidal load. |
Wine Condition Card: Clarification and Stabilization
Condition 06 | Fine Powder Residue After Bentonite Treatment
| Item | Recommendation |
|---|---|
| On-site Performance | Fine mist in white or rosé wine; powder-like layer on the surface of the final membrane. |
| Judgment | Bentonite and protein aggregates have not settled sufficiently. |
| Route | Sufficient settling/centrifugation → 3–5 µm depth filtration → 1 µm protection → final membrane. |
| Product | High-capacity PP or depth filter plates; do not use terminal PES to carry residual clarifying agents. |
Condition 07 | Tartaric Crystals Enter the Filtration Line After Cold Stabilization
| Item | Recommendation |
|---|---|
| On-site Performance | Increase in particle count during cold filtration; hard crystals in pumps, valves, and filter cartridges. |
| Judgment | Tartaric crystals have not been completely separated, and the data changes after heating. |
| Route | Low-temperature retention → Sedimentation/Centrifugation → 10–20 µm intercepts large crystals → 3–5 µm fine filtration → final membrane. |
| Product | Regenerable coarse filtration + deep protection; the final membrane is not used as a crystal collector. |
| Acceptance | Filtering temperature, cold stability test, pressure difference, and tartaric acid residue. |
Operating Condition 08 | Terminal filter suddenly clogs after CMC addition.
| Project | Recommendation |
|---|---|
| On-site Performance | Turbidity increases after stabilizer addition, especially in rosé or deeply colored wines; filter life drops drastically. |
| Judgment | CMC mixing is uneven, the wine has not reached protein stability, or it is incompatible with previous treatments. |
| Route | Protein stabilization first → Thorough mixing → CMC added at least before 48 h → Cold stability and membrane sheet testing → Final filtration. |
| Product | Deep protection with 1–3 µm may be necessary; it cannot be solved by changing to a smaller pore size. |
| Acceptance | Thermal stability, cold stability, NTU, FI/Vmax and color. |
Operating condition 09 | Colloidal load due to arabic gum, mannoprotein or pseudo-tartrate.
| Project | Recommendation |
|---|---|
| On-site performance | NTU changes little after addition, but final membrane flux decreases. |
| Judgment | Protect colloids or large molecules from interaction with the membrane or wine polyphenols. |
| Route | Define addition order and wait time → Conduct actual formula trials with the same material membrane → Move addition point to a validated location if necessary. |
| Product | Use low adsorption PES for final membrane; upstream use 1–3 µm for depth filtration. |
| Acceptance | Compare FI/Vmax, sensory and component recovery before and after addition; do not rely solely on NTU. |
Operating condition 10 | Color or aroma concerns after filtration.
| Project | Recommendation |
|---|---|
| On-site Performance | The red wine buyer is concerned that 0.45 µm may 'strip color' or weaken the mouthfeel. |
| Evaluation | The impact comes from medium adsorption, over clarification, and pre-treatment, not just the pore size alone. |
| Approach | Compare the unfiltered, crossflow, depth, 0.65, and 0.45 µm; control oxygen and temperature rise. |
| Product | Low adsorption hydrophilic PES final membrane; avoid loading the final membrane with large amounts of colloids. |
| Acceptance | Color, tannin/polymer, sensory triangle test, dissolved oxygen. Industrial testing shows that proper sequential filtration has a minimal impact on color. |
Wine Condition Card: Bottling Final
Condition 11 | Dry white wine, conventional bottling
| Project | Recommendation |
|---|---|
| On-site Performance | <1 NTU, good filtration; target is clarity and microbial stability. |
| Approach | 1–3 µm depth/complex pre-filtration → 0.45 µm hydrophilic PES → sterilized bottling line. |
| Small Batch Configuration | 10 inch single core or equivalent capsule filter; test based on actual wine volume. |
| Large Line Configuration | Parallel multiple core housings, designed to match flow rate with bottling machine, retaining a 20–30% area margin. |
| Acceptance | Integrity testing, pre- and post-filtering, NTU, pressure difference, dissolved oxygen. |
Operating Condition 12 | Dry Red Wine, High Gelatin Content
| Project | Recommendation |
|---|---|
| On-site Performance | Dark color, high gelatin, 0.45 µm filter life variability. |
| Route | Crossflow or depth module → 3 µm → 0.8–1.2 µm protection → 0.65 or 0.45 µm final membrane. |
| Precision Selection | Evaluate 0.65 µm only for yeast control with low microbial risk; prioritize validation of 0.45 µm for lactobacillus/Brett control. |
| Product | Low adsorption PES; final membrane must be integrity testable. |
| Acceptance | FI/Vmax, Brett/Lactobacillus Detection, Color and Aroma Analysis |
Operating Condition 13 | Sweet Wine or High Residual Sugar, Risk of Post-Bottling Fermentation
| Item | Recommendation |
|---|---|
| On-Site Performance | Residual sugar, incomplete cold fermentation, or yeast dormancy; a small number of survivors can cause bottle pressure and haziness. |
| Route | Full clarification → 1 µm protection → Post-fermentation with yeast/bacteria validated 0.45 µm; assess 0.2/0.22 µm and other legal bioburden reduction measures when high risk. |
| Product | PES terminal membrane; use disposable capsule filters for small batches to reduce secondary contamination. |
| Acceptance | Yeast cultivation requires sufficient time; confirm residual sugar, SO2, pH, bottling hygiene, and storage temperature. |
Operational Condition 14 | Low Alcohol or Zero Alcohol Wine
| Project | Recommendations |
|---|---|
| On-site Performance | Alcohol protection decreases, protein/polymer/tartaric crystal balance changes, and risk of bacteria and osmophilic yeasts increases. |
| Route | Post-de-alcohol re-evaluation of clarification and stabilization → 1–3 µm deep → 0.45 µm；risk assessment may allow for 0.2/0.22 µm. |
| Product | Hydrophilic PES final filter cartridge or capsule；do not follow standard wine shelf life data. |
| Acceptance | Low alcohol formulation challenges, shelf life, target microorganisms, integrity, and ultra-clean bottling. |
Condition 15｜Malolactic fermentation not confirmed complete
| Project | Recommendation |
|---|---|
| Field performance | Malic acid residue, high pH, or viable lactic acid bacteria still present. |
| Route | Confirm MLF status and process objectives → 1 µm protection → 0.45 µm terminal with lactic acid bacteria validated. |
| Stringent conditions | For higher bacterial assurance, conduct 0.2/0.22 µm capacity and component recovery tests. |
| Acceptance | Malic acid, lactic acid bacteria cultivation, integrity, and post-filter aseptic boundary. |
Condition 16｜Risk of Brettanomyces in red wine
| Project | Recommendations |
|---|---|
| On-site Performance | Risk of volatile phenols in barrel-aged wines; post-treatment culture results with 2 are unstable. |
| Route | Zone and hygiene control → if necessary, reduce load with crossflow filtration → 0.8–1.2 µm warning level → 0.45/0.65 µm final sterile packaging. |
| Evidence | Specific Brettanomyces strains are retained by the ≤0.8 µm membrane in published studies; OIV recommends 0.45–1 µm membrane or crossflow filtration as control methods. |
| Acceptance | Do not rely solely on short-term cultures; extend the culture period or use molecular detection to verify post-packaging samples. |
Condition | Yeast or bacteria detected post-filtering
| Project | Recommendations |
|---|---|
| On-site Performance | Correct pore size of final filter, but positive cultures in the finished product. |
| Sequence of Investigation | Bypass/O-ring → filter integrity → shell venting and assembly → post-filter tubing/buffer tank → filling valve and cap. |
| Action | Isolate batch; do not immediately attribute to pore size; retest integrity and environmental samples. |
| Acceptance | Samples before and after filtration, samples at the filling head, blank water, and samples after packaging. |
Wine Condition Card: Sparkling Wine and Small Batch
Condition 18 | Traditional Method Sparkling Wine: Base Wine and Pre-bottling Tirage
| Item | Recommendation |
|---|---|
| On-site Performance | The base wine should be clear, but it needs to be inoculated with secondary fermentation yeast later. |
| Route | Base wine clarification/stabilization → 0.45–1 µm membrane filtration → Add the tirage formula and target yeast under controlled conditions → Bottle. |
| Product | Small batch additions can use 0.45 µm PES capsule filter; main volume uses pleated filter cartridge. |
| Acceptance | Ensure membrane integrity before addition, target inoculation volume, and avoid filtering out the secondary fermentation yeast. |
Condition 19 | Traditional Method Sparkling Wine: Post-racking Supplement / dosage
| Item | Recommendation |
|---|---|
| On-site Performance | The dosage volume is small and contains sugar, and there is no space for secondary fermentation after it enters the finished product. |
| Route | Dosage formulation separate clarification → 1–3 µm small capsule protection → Verified 0.45 µm PES capsule → Aseptic connection to the dosage segment. |
| Product | Low retention volume capsule is better than large housing; select sanitary quick connect or aseptic connection for the interface. |
| Acceptance | Capsule integrity, formula component recovery, interface sterilization, and finished product cultivation after dosage. |
Operational Condition 20 | Tank Sparkling Wine: With CO2 isobaric filtration
| Project | Recommendation |
|---|---|
| On-site Performance | After secondary fermentation, yeast lees are present, and depressurization can cause foaming and loss of CO2. |
| Route | Cooling → Isobaric crossflow/clarification → 1–3 µm protection → 0.65/0.45 µm isobaric final → Isobaric bottling. |
| Product | The housing and filter cartridge must confirm the positive, reverse, and CO2 operational conditions; ensure thorough purging to avoid air blockage. |
| Acceptance | CO2, pressure, foam, turbidity, microbiology, and dissolved oxygen. OIV process clearly includes isobaric filtration. |
Operating Condition 21｜Small Winery or Home Winemaking, Batch Size from Several to Hundreds of Liters
| Project | Recommendation |
|---|---|
| On-site Performance | Few pieces of equipment, frequent batch changes, short hygiene boundaries, low filter cartridge utilization rate. |
| Route | Resting/Transfer → 5–10 µm Plate Frame or Depth Depth Capsule Filter → 1–3 µm → 0.45/0.65 µm Capsule Filter or 10 Inch Single Core → Direct Filling. |
| Selection | Capsule Filters are suitable for low retention, rapid batch changes; reusable housings are suitable for stable batches and hot water regeneration. |
| Acceptance | Record volume and pressure difference for each batch; do not skip hygiene, venting, and integrity testing due to small batch size. |
Operating Condition 22｜Mobile Bottling Service
| Project | Recommendation |
|---|---|
| On-site Performance | Continuous switching between different wineries and different wine types; significant fluctuations in upstream wine quality. |
| Route | Arrive on site, measure NTU + FI/Vmax → Configure switchable 3/1/0.8 µm protective stage → Final 0.45/0.65 µm terminal stage. |
| Product | Multi-stage housing with bypass and sampling ports; final connection with dual O-ring interfaces. |
| Acceptance | Integrity testing, CIP records, microbial analysis of first and last bottles, batch traceability for each batch. |
Fault Diagnosis
Fault 01 | NTU<1, final membrane rapidly clogs despite proper operation.
- Possible causes: dextran, pectin, mannoproteins, CMC, arabic gum, polyphenol aggregates, or bacteria.
- Immediate action: Stop increasing pressure; take same batch wine with same membrane material for FI/Vmax; check addition time and temperature.
- Solution: Add depth filtration stage, extend stabilization time, or perform enzyme treatment; do not directly replace 0.45 with 0.2 µm.
Fault 02 | Sudden pressure drop, not gradual increase.
- Possible causes: valve position error, pump surge, air lock, increased viscosity at low temperatures, crystal aggregates, or filter cartridge installed in reverse.
- Immediate action: Reduce flow rate, vent air, check temperature and valve position; do not exceed filter manufacturer limits.
- Solution: Add soft start, high point venting in housing, and pre-filtration monitoring.
Fault 03 | Flow rate normal but detectable post-filtration.
- Possible causes: bypass, seal damage, integrity failure, post-filter contamination.
- Immediate action: Isolate product, perform filter integrity testing and point-of-use cultures.
- Solution: Use sanitary interfaces, shorten post-filter tubing, establish a sterile boundary from filter to bottle neck.
Fault 04 | Integrity fails after hot water/steam treatment.
- Possible causes: dry steam impact, excessive pressure differential, thermal cycle limit exceeded, seal deformation.
- Immediate action: stop use; check wetting state, inlet and outlet pressure and temperature records.
- Solution: set hot water/steam program according to filter cartridge validation conditions; request cumulative cycle data during procurement.
Fault 05 | Increase in dissolved oxygen after filtration.
- Possible causes: shell not precharged, excessive venting, pump intake of air, large headspace in buffer tank.
- Solution: inert gas displacement, low point liquid feed high point venting, shorten transfer, avoid spray return.
- Acceptance: dissolved oxygen and total package oxygen before and after the filter.
Fault 06 | Fluctuation in sparkling wine flow, bubble curtain membrane face.
- Possible causes: CO2 release due to pressure drop, high point gas accumulation in shell.
- Solution: maintain back pressure and low temperature, use isobaric filtration, continuous high point venting without causing loss of CO2.
- Acceptance: inlet and outlet pressure, CO2, foam, and flow stability.
Scalable Configuration
Small Winery and Home Winemaking
| Batch | Recommended Structure | Explanation |
|---|---|---|
| 1–50 L | Filter Sheet/Small Capsule | Experiments, additives, formula validation; prefer low retention volume |
| 50–1,000 L | 5–10 µm depth capsule → 1–3 µm → capsule filter of 0.45/0.65 µm inches or 10 inch single core | Use single-use paths for multiple batches; use cleanable housings for stable batches |
| 1–10 m³ | plate frame or lens or small crossflow → 1 µm → 10/20 inch final membrane | Need buffer tanks, sampling points, and integrity interfaces |
Large-scale Continuous Winemaking and Bottling
| Process stage | Recommended structure | Design focus |
|---|---|---|
| Cellar clarification | Centrifugation, soil filtration, pressure leaf filtration, or crossflow | Continuous dewatering, liquid loss, cleaning recovery rate |
| Preparation for bottling | 3–5 µm Depth Filtration Module → 0.8–1.2 µm Pleated Pre-filter | Reduce colloidal and microbial load on the final membrane |
| Final | Multi-core 0.45/0.65 µm PES housing | Match flow rate to bottling, online integrity testing, spare housing or parallel switching |
| High-risk products | 1 µm → 0.45 µm, 0.2/0.22 µm if necessary | Low alcohol, sweet wines, and bacterial risks require separate validation |
Case study summary
Case 01 | Industrial-scale red wine sequential filtration
- Conditions: Commercial Cabernet and Shiraz using 4, two vintages, two quality grades.
- Path: Crossflow → Lens → 0.65 µm membrane → 0.45 µm membrane.
- Results: Crossflow removes the most particles; subsequent fine filtration has no significant adverse effect on tannin, polysaccharide composition, and color.
- Application: For high-end red wines, the use of 0.45 µm should be judged based on colloidal, microbial, and pilot test results, not by the conclusion that 'red wine cannot be ultrafiltered'.
Case 02 | Malvar white wine crossflow clarification
- Conditions: Using crossflow membranes for white wine clarification compared to traditional filtration.
- Conditions: Literature reports transmembrane pressure difference at 0.7 bar results in a flux of approximately 48–49 L/m²·h.
- Results: Obtained clear wine, as a pre-treatment for subsequent stabilization and bottling filtration.
- Application: This flux is only applicable to the literature equipment and wine, and cannot be directly used for other membrane area quotations.
Case 03 | Clarification of grape juice and red wine substrates by hot maceration
- Operating Conditions: 2017 Year Italian Winery, Hot Maceration of Grape Juice and Static Clarification of Substrate with High Solids Content.
- Route: Static/Dynamic Ceramic Crossflow Compared with Vacuum Drum Filtration.
- Results: Crossflow Filtration Has Lower Hourly Capacity but Better Analytical and Economic Efficiency, Reducing Operating Costs While Maintaining Product Quality.
- Application: For High Solids, Use Specialized Crossflow or Drum Filtration Instead of Relying on Terminal Pleated Membrane Filtration.
Case Study: 04 | Gelatinous Plugging of Botrytis Rotted Grapes
- Operating Conditions: Membrane Pressure Differential Rises Rapidly with High Proportion of Rotten Fruit, Shortening Backwash Cycles.
- Mechanism: Pectin, Botrytis Glucans, and Yeast Autolysis Polysaccharides Form a Viscous Layer.
- Solution: Add Compliance Glucanase During the Late Fermentation Phase Using Residual Heat; Clarify Thoroughly Before Depth and Terminal Filtration.
- Application: Official German Technical Literature States That SO2 Does Not Inhibit Enzyme Activity; Timing Still Needs to Be Verified by Alcohol Content, Temperature, and Product Specifications.
Case Study: 05 | CMC Plugging After Addition
- Operating Conditions: White/Pink Wine for Tartar Stabilization; Some Red Wines Show Color Substance Instability and Turbidity Increase.
- Solution: First confirm protein stability and mix thoroughly; add CMC at least 48 h before final filtration and perform a cold-stability test.
- Application: If Filtration Index (FI)/Volume Ratio (Vmax) Worsens After Addition, Address Colloids or Increase Depth Filtration Level, Do Not Replace with Smaller Terminal Membrane.
Case Study: 06 | Small Winery Filtration at the Winery
- Operating Conditions: Low Batch Size, Limited Own Equipment, Bottling Often Completed by Mobile Services.
- Route: Plate Frame/Prism or Small Crossflow → Buffer Tank → Pre-Filtration Pleated Filter Cartridge → Terminal Membrane Filtration.
- Conclusion: Crossflow Filtration Followed by a Buffer Tank Still Poses a Risk of Recontamination, Therefore, Retain Terminal Membrane Before Bottling Line.
Case Study: 07 | Membrane Validation for Bottling Line 0.45 µm
- Operating Conditions: Public process validation in Portugal, membrane filtration used for bottling stage.
- Control: Record integrity for each bottling; the facility uses the differential pressure between the filter chamber 1.5 bar as the control value.
- Conclusion: The 0.45 µm membrane is effective in this process; 1.5 bar is a single-site value and does not replace the manufacturer's limit values.
Case Study 08 | Brettanomyces Filtration Retention
- Operating Conditions: Red wine inoculated with two Brettanomyces strains, comparing SO2 treatment with different pore sizes.
- Results: One strain is retained by the 1.2 µm; another strain shows delayed growth after 1.2 µm, but can be removed by 0.8 µm.
- Application: Do not use the 1.2 µm as a general Brettanomyces guarantee; strictly bottle using the 0.45/0.65 µm and validate target microorganisms.
Case Study 09 | Microbial Risk in Low-Alcohol Wines
- Operating Conditions: Alcohol protection decreases after de-alcoholization, with increased risk of fermentation in the bottle due to sugar addition.
- Results: Research supports the use of microfiltration and ultra-clean bottling to reduce yeast, lactic acid bacteria, and acetic acid bacteria loads.
- Application: Low-alcohol products should revalidate the 0.45 and 0.2/0.22 µm capacities and shelf life, not using general wine parameters.
Case Study 10 | Isobaric Filtration of Tank Sparkling Wines
- Operating Conditions: After secondary fermentation in a closed tank, the wine needs to be separated from lees and retain CO2.
- Process: Cooling/Stabilization → Isobaric Filtration → Dosage Addition → Isobaric Bottling.
- Application: Final filter not only removes microorganisms but also needs to verify positive pressure, reverse pressure, venting, and CO2 outgassing conditions.
Case Study 11 | Membrane Clogging Despite Acceptable NTU
- Operating condition: Wine is <1 NTU before bottling and visually clear, yet the 0.45 µm membrane still clogs rapidly.
- Conclusion: NTU mainly reflects scattering particles, but does not reflect the full risk of colloidal clogging.
- Solution: Use 25 mm and 0.45 µm membranes for filtration with the 2 bar and actual wine temperature; the membrane material should be as consistent as possible with the production terminal.
Case Study 12 | Differences in Filtration Routes Between Large and Small Wineries
- Conditions: Investigate by grouping based on annual processing volume of <50 t, 50–1,000 t, 1,000–10,000 t, and ≥10,000 t.
- Results: Crossflow filtration is more common at >50 t winery; large wineries commonly use 0.45 µm terminal membranes for white wine; high-end red wines have two routes with coarse filtration and 0.45 µm.
- Application: Equipment scale affects process combinations, but the terminal pore size is still determined by microbial risk and filtration requirements.