When you savour a glass of wine, its clarity and the wine’s essence. Yet, achieving that pristine state involves a meticulous filtration journey within the winery's walls. Let's uncork the process and explore the three stages of filtration that transform grapes into liquid gold.
Coarse Filtration: Setting the Stage for Elegance
This critical step, known as coarse filtration, aims to eliminate larger particles like yeast cells and tartaric acid crystals, laying the foundation for a smoother and refined final product.
Traditionally, wineries relied on diatomaceous earth (DE), powder filtration or filter sheets after the finning process. However, modern technology introduces alternatives like lenticular or stacked disc solutions, crossflow filtration, and cartridge filtration, revolutionising the options that can be used in the standardisation process.
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Filterability index (FI) testing quickly evaluates a wine's filter blocking potential. It involves passing the wine through a 0.45μm filter disc at a consistent 2barg pressure and measuring filtration times for 200ml and 400ml. The difference between these times decides the FI result, with a low value (<20) suggesting low blocking potential and a high value (>20) showing potential for blockage. |
But why is standardization crucial? Beyond enhancing clarity and stability, it ensures microbial stabilisation and minimises sulphur dioxide usage. Wine contamination after finning can vary widely, posing a challenge for single filtration system when handling wines of diverse qualities. Quick assessments, often through Filterability Index (FI) testing, guide the tailoring standardisation processes to perfect the wine quality before packaging while keeping reasonable filtration service life.
In essence, coarse filtration isn't merely about removing particles—it's about safeguarding wine integrity.
The Essence of Fine Filtration: Elevating Elegance
Fine filtration marks the next step, focusing on eliminating remaining particles and preparing wine for final filtration. This stage is pivotal for achieving the clarity and brilliance cherished by wine enthusiasts worldwide. Fine filters are typically either glass fibre or polypropylene pleated cartridges.
Fine filtration plays a pivotal role in:
- Producing a Bright Wine: By eliminating even the tiniest particles, fine filtration enhances visual appeal.
- Prefilters for Particle Retention: Acting as the next line of defence, prefilters capture fine particulate matter, prolonging the lifespan of final membrane filters and ensuring cost-effective filtration.
- Microbial Validation: In certain cases, prefilters require microbial retention consideration, emphasising the need for prefilters that protect against both particles and microbial contaminants. In certain cases, wines are solely filtered through prefilters, but ensure the removal of Brettanomyces to the required levels.
In conclusion, fine filtration isn't just about clarity; it's about preserving wine quality and integrity prior to the final bottling.
Sterile Filtration: Safeguarding Perfection
Achieving microbial stability and preserving wine integrity culminates in sterile filtration. This meticulous process involves passing wine through membrane filters, removing potential spoilage organisms just before bottling.
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Different wines require specific filtration standards, with red wines typically using a 0.65 micron membrane filter, while whites demand a finer 0.45 micron filter. But it's not just about removing contaminants; it's about preserving wine essence. Membrane filters undergo rigorous validation to ensure they retain spoilage organisms while preserving essential characteristics like sweetness, acidity, and tannin levels.
Key spoilage organisms, including Saccharomyces and Brettanomyces, are targeted for removal, with membrane filters made of materials like PES and PVDF offering reliable retention.
Moreover, these filters meet stringent criteria, ensuring integrity, high flow rates, and compatibility with sterilisation methods, guaranteeing cleanliness and safety.
In essence, sterile filtration safeguards the essence of wine, ensuring every sip is as delightful as the first. So, as you raise your glass, toast to the meticulous process preserving perfection in every pour. Cheers!
If you'd like more information on wine filtration or more broadly around food & beverage filtration or spirit filtration, then get in touch with us HERE or via our contact form. We'd love to her from you.
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