Filter Sheet Selection Guide | GW Kent

Filter Sheet Selection Guide

Choosing the right filter sheet grade can make the difference between a smooth filtration run and premature clogging. This guide helps you match your filtration needs to the appropriate filter sheet grade based on your product, clarity goals, and filtration stage.

Quick Selection Decision Tree

Start here to narrow down your options:

1. What's your filtration goal?

Rough polishing (removing yeast, large particles) → K900, K800, K700
Clarity/polishing (clear product, visible haze removal) → K300, K250, K200, K150, K100
Sterile/pre-membrane (microbial reduction before bottling) → KS80, KS50, EK, EK1, EKS
Color/odor removal (activated carbon filtration) → Activated Carbon Sheets

2. What are you filtering?

Wine → Standard K-Series grades work well
Beer → K300 most common for keg Beer; tighter grades for bottling
Spirits → K200-K100 for polishing; KS80-EK for brilliant finish
Cider/Mead → Start coarser (K700-K300) due to higher colloid content

3. What's your starting clarity?

Cloudy/hazy → Start with coarser grades (K700-K300) to avoid premature clogging
Already clear → Can use finer grades (K200-EK) for final polish
Unknown/variable → Consider two-stage filtration (coarse → fine)

Complete Grade Selection Chart

Grade	Micron Rating	Primary Use	Typical Applications
ROUGH POLISHING - Particle & Yeast Removal
K900	9-10 micron	Coarsest filtration	Removing large particles, yeast sediment, rough polishing of dark beers
K800	7-8 micron	Rough polishing	Yeast removal, first-stage filtration, dark/amber beers
K700	5-7 micron	Polishing filtration	Yeast removal, polishing of amber beers, first stage for cider/mead
CLARITY/POLISHING - Clear Product Filtration
K300	3-4 micron	Polishing clarity	Clear wine polishing, most common for keg beer, standard clarity filtration
K250	2.5 micron	Polishing clarity	Clear wine polishing, light beer clarification
K200	2.0 micron	Higher polishing	Clear wines, bright beer for bottling, spirits polishing
K150	1.5 micron	Higher polishing	Clear wines, bright spirits, pre-sterile filtration
K100	1.0 micron	Highest polishing	Brilliant clarity, spirits finishing, pre-membrane protection
STERILE/PRE-MEMBRANE - Microbial Reduction
KS80	0.8 micron	Yeast-sterile filtration	Beginning of sterile grades, yeast removal for bottling
KS50	0.5 micron	Pre-membrane sterile	Yeast-sterile bottling, pre-membrane (0.65µ) protection
EK	0.45 micron	Sterile bottling	Pre-membrane (0.45-0.65µ) filtration, sterile bottling
EK1	0.35 micron	Tight sterile filtration	Difficult-to-filter wines, tight pre-membrane protection
EKS	0.25 micron	Tightest sterile grade	Most challenging products, maximum pre-membrane protection

Important: Micron ratings are nominal, not absolute. They indicate typical particle retention based on standard test conditions. Actual performance varies with product characteristics, flow rate, and differential pressure.

Equipment Sizing Guidelines

Filter Sheet Size: 40×40 cm Standard

GW Kent stocks primarily 40×40 cm filter sheets, which offer the best economy and flexibility:

Effective filter area: 1.54 ft² (0.143 m²) per sheet

For 20×20 cm presses: Cut 40×40 sheets into quarters for cost savings

Plate & Frame Filter Sizing

Rule of thumb for plate count:

9 plates → 3 bbl batch
20-30 plates → 15 bbl batch
30-40 plates → 25 bbl batch

These are general guidelines. Actual capacity depends on product filterability, desired flow rate, and grade selection.

Optimal Flow Rates (40×40 cm sheets)

Filtration Type	Wine (gal/hr/sheet)	Beer (bbl/hr/sheet)	Max Differential Pressure
Sterile (KS80-EKS)	20 gal/hr	0.20 bbl/hr	21 psi (1.5 bar)
Polishing (K100-K700)	35 gal/hr	0.60 bbl/hr	45 psi (3.0 bar)

Pro Tip: Operating at higher flow rates increases differential pressure and can cause premature clogging. Start conservative and increase flow gradually while monitoring pressure.

Two-Stage Filtration Strategy

For challenging products or maximum filter life, use a diverter plate to run two grades in series:

Configuration: Coarse sheets (inlet side) → Diverter Plate → Fine sheets (outlet side)

Example combinations:

Cloudy beer: K700 → K300 (removes solids first, then polishes)
Sterile wine: K300 → EK (protects expensive sterile sheets)
Difficult cider: K700 → K200 (handles high colloid load)

Benefits: Extended sheet life, improved clarity, reduced clogging risk, better economics

Troubleshooting Common Issues

Problem: Sheets clog too quickly (high differential pressure)

Solutions:

Switch to a coarser grade (e.g., K300 → K700)
Implement two-stage filtration
Reduce flow rate
Check product filterability (run bench test)
Ensure proper settling/fining before filtration

Problem: Product isn't clear enough after filtration

Solutions:

Use a finer grade (e.g., K300 → K200 or K100)
Run a second pass through same or finer grade
Check that product was properly settled first
Consider if clarity issue is colloidal (may need fining agents)
Verify filter sheets are installed with rough side toward inlet

Problem: Inconsistent results between batches

Solutions:

Standardize your fining/settling protocols
Monitor differential pressure consistently
Ensure proper sheet installation (rough side to inlet, smooth side to outlet)
Check that all sheets are the same grade (laser-etched markings)
Maintain consistent flow rates

Sheet Regeneration & Reuse

K-Series sheets can be regenerated to extend throughput and improve economics:

Regeneration protocol:

Rinse with warm water (60°C / 140°F) for 15 minutes
Rinse with hot water (70-80°C / 158-176°F) for 8-10 minutes
Maintain back pressure of 0.5-1 bar during rinse

Expected cycles:

Hot water regeneration: Up to 30 cycles
Steam sterilization: Up to 20 cycles

Important for reverse flow regeneration: Use particle-free, microbe-free water to avoid contaminating the filtrate side. If sheets won't be sterilized before reuse, water must be sterile.

Activated Carbon Filter Sheets

For applications requiring color or odor removal, activated carbon sheets combine mechanical filtration with chemical adsorption:

Applications:

Decolorization of spirits and liqueurs
Removal of off-odors or flavors
Reduction of certain organic compounds
Treatment of over-oaked wines

Available grades:

Pall Activated Carbon Sheets: General-purpose carbon filtration
Micro-Clear Carbon Sheets: Premium carbon media for craft beverage applications

Note: Carbon sheets are typically not regenerable. Single-use application recommended for best results.

Product Compliance & Quality

All filter sheets meet rigorous food contact standards:

FDA 21 CFR Part 177 (U.S. food contact materials)
EC 1935/2004 (European food contact regulations)
USP Plastics Class VI - 121°C (pharmaceutical grade)
ISO 9001:2008 certified manufacturing

Main constituents: Cellulose, diatomaceous earth (DE/Kieselguhr), perlite

Traceability: Each sheet is laser-etched with grade, batch number, and production date

Available Products

Filter Sheets (40×40 cm)

Pall Seitz K-Series Filter Sheets (EKS-K900) Pall Filter Sheets - Standard Grades BECOPAD Filter Sheets (40×40 cm)

BECOPAD sheets are mineral-free depth filtration media suitable for coarse to sterile filtration

Activated Carbon Sheets (40×40 cm)

Pall Activated Carbon Filter Sheets Micro-Clear Activated Carbon Sheets

Plate & Frame Filter Presses

ProLine Plate & Frame Filter (40×40 cm, various plate counts)

Available in 9, 20, 30, and 40 plate configurations with optional diverter plate for two-stage filtration

Letina Plate & Frame Filter - 30 Plate (40×40 cm) Pico Plate & Frame Filter - 30 Plate (20×20 cm)

For 20×20 cm filters, cut 40×40 cm sheets into quarters for economy

Technical Resources

For complete technical specifications, installation instructions, and operating procedures, download our product documentation:

K-Series Filter Sheet Specifications - [ Download ]
BECOPAD Filter Sheet Technical Data - [ Download ]

Need help selecting the right filter sheets?

Our technical team can help you choose the optimal grades and equipment for your specific application.

Contact Our Technical Team