Wine Clarification & Stabilization

Wine is a complex product constantly evolving from the moment the fermentation is complete right up to the time the cork is pulled. This complexity enables winemakers to deliver the individual appeal of each wine, however, this evolution can also lead to the formation of sediments and hazes that are not desirable in the finished product. 

Winemakers use wine stabilization and clarification techniques to improve the visual appearance and shelf stability of their wines.

1. Post fermentation – Which is composed mostly of dead yeast cells (lees), bacteria, grape skins, grape seeds and tartrate crystals.
2. During ageing – The proteins, phenolics, tannins and polysaccharides combine in various ways depending on the nature of the wine, leading to amorphous hazes and/or deposits. 
3. At low temperature – The Bitartrate instability at low temperatures, can lead to significant deposits of tartrate crystals, which are harmless but can have an appearance similar to glass in white wines.

Winemakers have several filtration methods available when clarifying wine, each has its own pros and cons which are further explained below.

Sheet filters have been used for wine clarification for over 130 years and continue to be used in smaller wineries throughout the world. 

For smaller wineries that need the flexibility to produce a variety of small batches, sheet filtration in plate and frame format can demonstrate advantages from both an economic and operational standpoint.

Lenticular modules, a modern adaptation of sheet filters assembled in an enclosed housing, avoid drip losses and provide additional flexibility, hygiene and ease of use.

Diatomaceous Earth (DE) filtration, also known as Kieselguhr filtration, was once the most common method for wine clarification on the larger scale. More recently DE has commonly been replaced by crossflow filtration equipment in all of the world’s winemaking regions.

Crossflow membrane systems enable cost savings by reducing wine loss, consumables and labor typically associated with filter aid based technologies. Furthermore, with a DE - free process and no solid waste for landfill, both environmental and operator safety are improved. 

Wine clarification using centrifugation is typically used at the larger wineries and is generally followed by a crossflow filtration system in order to achieve the clarity needed prior to bottling.

Settling by gravity combined with the addition of fining agents may also used but requires a significant amount of time that many modern wineries do not consider to be efficient.