Selecting the correct membrane pore size is critical to achieving microbial stability without unnecessary cost, pressure drop, or flavour risk. In beer filtration, membrane ratings are typically expressed as particulate or absolute micron sizes, with the most common options being 0.65 µm and 0.45 µm absolute in sterile beer filtration applications.
Understanding what each rating does—and when to use it—helps brewers design a filtration process that is both robust and economical.
0.65 µm membranes are primarily used for yeast removal rather than full microbial stabilisation.
In practice, 0.65 µm membranes are often used as a final clarification step, not as true sterile filtration.
0.45 µm membranes are widely regarded as the benchmark for sterile beer filtration.
For most breweries seeking a pasteurisation alternative, 0.45 µm absolute-rated membranes represent the optimal balance of security and performance.
While finer membranes are common in pharmaceutical or water applications, they are generally unnecessary for beer.
Unless filtering highly contaminated process streams (which indicates upstream issues), sub-0.45 µm ratings offer little benefit in brewing.
Membrane rating should never be considered in isolation.
A well-designed depth pre-filtration stage allows:
Without adequate pre-filtration, normally pleated depth filters, even the correct membrane rating will underperform.
|
Objective |
Recommended Final Rating |
|
Yeast removal only |
0.65 µm |
|
Sterile, shelf-stable beer |
0.45 µm |
|
Export / warm storage |
0.45 µm (with integrity testing) |
|
Pasteurisation replacement |
0.45 µm |
Beyond pore size, the membrane polymer itself plays a major role in filtration performance, cleanability, and long-term reliability. In beer sterile filtration, polyethersulfone (PES) and polyvinylidene fluoride (PVDF) are the two most commonly used membrane materials.
Each has strengths that make it suitable for specific brewing conditions.
PES membranes are widely used in beverage filtration due to their high permeability and neutral interaction with beer components.
In practice, PES membranes are often selected where maximum throughput and minimal flavour interaction are the primary goals.
PVDF membranes are valued for their mechanical durability and chemical resistance, making them attractive in more demanding operating environments.
PVDF membranes are often chosen for process resilience and longevity, particularly in large or highly automated breweries.
|
Requirement |
Preferred Material |
|
Maximum flow rate |
PES |
|
Minimal flavour interaction |
PES |
|
Aggressive CIP regimes |
PVDF |
|
High mechanical robustness |
PVDF |
|
Frequent batch cycling |
PVDF |
|
High-throughput craft packaging |
PES |
In many breweries, both materials perform well. The optimal choice depends less on beer style and more on process conditions, cleaning strategy, and operational discipline.
Sterile membrane filtration has become a cornerstone of modern brewing, offering a proven way to deliver microbiologically stable beer without compromising flavour, aroma, or freshness.
When correctly designed, a sterile filtration system:
Rather than being a single component, sterile filtration is a system-level solution. Success depends on understanding how filter ratings, membrane materials, and upstream process control interact.
For breweries seeking an alternative to pasteurisation—or a way to protect delicate, flavour-driven beers—cold sterile filtration remains one of the most precise and controllable tools available.
If you have any questions about brewing filtration or sterile beer filtration more specifically, then give us a call or send us an email - we’d be more than happy to help.
And here are a few more blogs and links that you might find useful:
PoreFiltration – Making your filtration systems work harder