The STS system, supplied by Separator Technology Solutions, is a superior method for winery solids management and eliminates the need for racking juices and wines and the consequent product losses and quality or value downgrades. 

Central to the system is the STS series, a disk-type centrifuge with the capability to both process entire tanks of juice and wine, including the lees, and eject the solids at such a thickness (e g 95% v/v) that no further product recovery is necessary (e g via Lees Filter or RDV Filter).

A major South African wine group, Distell (Bergkelder), based in Stellenbosch, has successfully validated financial paybacks of less than one year for the STS 200 system. Senior winemakers of the wine division oversaw these validations and can confirm the winemaking and cellar operations benefits and business case for integrating the STS 200 technology into South African wineries.

The principal sources of financial payback for the STS 200 are:

• Reducing juice and wine losses associated with racking or desludge from older centrifuges. This occurs in two parts, firstly where lees are sent to distillation, (e g to Brenn-O-Kem) and secondly, the reduced number of lees transfers leads to a dilution of yield losses. 
• Reduced juice and wine quality/value downgrades. This is where existing lees handling processes lead to loss of quality and value, by loss of freshness and oxidation, loss of varietal or regional integrity and character, or finally anoxic/reductive taints from prolonged exposure to high concentrations of yeasts and bacteria in the lees. 
• Eliminating DE filtration, principally the Lees Filter and Rotary Drum Vacuum (RDV) filter. The direct hard savings in reduced DE consumption are typically modest in the financial justification of the STS 200. However, the Occupational Health, Safety & Environment considerations of DE and the ability to proactively demonstrate a major reduction in DE usage in the cellar is an intangible benefit of the STS 200.

A key advance of the system over older centrifuges is very low oxygen pick-up as low as 0.02 mg of oxygen per liter of wine. This means the same wine can be centrifuged multiple times during its maturation cycle. The low oxygen pick-up allows South African cellars to maximize the financial benefits of the STS 200's broad spectrum of juice and wine solids removal capabilities.

The STS 200 system has been developed to handle a broad range of winery products, to ensure clients maximize the financial benefits of the technology. Key applications include clarification of:

• Whole white juice
• Cold-settled juice lees
• White wine ex-primary ferment (including yeast lees)
• White wine ex bentonite (including bentonite lees)
• Bentonite lees
• Red wine ex-primary ferment (including gross lees)
• Gross red lees
• Red wine ex malolactic ferment
• Wines ex-cold stabilization
• Coarse polishing (prior to cross-flow)