Filtration in spirits isn’t just about clarity.
It’s about protecting brand reputation, preserving flavour, preventing returns, and ensuring every bottle looks exactly as the customer expects — whether it’s crystal-clear vodka or a rich, aged whisky.
While the equipment may look similar, light spirits and dark spirits behave very differently during filtration. Treating them the same can lead to haze, flavour loss, shortened filter life, or inconsistent bottling performance.
Here’s how — and why — the approach must change.
Typical products: Vodka, white rum, gin
Customer expectation: Absolutely clear — no haze, no sediment, no compromise
Consumers expect light spirits to look like pure water. Even slight haze after refrigeration can result in complaints or rejected shipments.
After dilution and carbon treatment, light spirits can contain:
When stored at 0–5°C, these compounds can form microscopic particles. They’re harmless — but visually unacceptable.
Remove Carbon Fines First
Carbon fines are soft and irregular.
If they reach the final filter, they cause rapid blocking.
Solution:
A depth cartridge or bag filter (typically 5–10 micron) upstream protects the polishing filter and significantly extends service life.
Final Polish with an Absolute Cartridge
For consistent clarity, an absolute-rated pleated cartridge (0.45–0.65 micron) is typically used.
This ensures:
Key point:
Always filter at the same temperature the product will experience during storage or distribution. Filtering warm and storing cold almost guarantees haze reappearance.
Distilleries implementing staged filtration typically see:
For light spirits, filtration is about precision and polish.
Typical products: Whisky, aged rum, cognac
Customer expectation: Clarity — without flavour loss
Dark spirits are more complex. They contain:
These give the spirit its depth and character — but they also make filtration more delicate.
Unlike vodka, whisky contains compounds essential to mouthfeel and aroma.
If filtration is too tight:
That’s why micron rating alone should never drive specification.
Coarse Stabilisation Stage
A depth cartridge or depth filter sheet (1–5 micron) removes:
Depth media works well because dark spirit particles are often deformable and broad in size distribution.
Controlled Final Filtration
Final polishing is typically done with an absolute 0.65–1.0 micron pleated depth cartridge.
Going tighter (e.g. 0.45 micron) can:
Maintaining moderate differential pressure is also critical — gelatinous particles can compress and pass through under excessive force.
When filtration is optimised:
For dark spirits, filtration is about balance — not maximum retention.
Across both light and dark spirits, one factor matters more than most producers realise:
Filtration temperature must match storage temperature.
Filtering at ambient conditions and distributing into cold markets is one of the most common causes of post-bottling haze.
Filtration isn’t simply a compliance step before bottling.
It’s a brand protection process.
Light spirits demand brilliance.
Dark spirits demand balance.
Understanding the difference ensures clarity without compromise.
If you have any questions about spirit filtration 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