Efficient separation equipment for effective wine production

Wine is a cultural asset. The grape vine is one of the oldest cultivated plants in the world, and its success story continues to advance. Lifestyle and consumption habits are changing all over the world and with the adoption of wines, wine making and viniculture to an expanding base of both consumers and producers globally, it represents great potential for the industry. However, even while rising to embrace these positive developments, we must address the most basic of challenges in its crafting. 

During the growth and development of the crop over a season, the resultant juice yield and fruit quality are subject to many factors, including those of grape varietal choice and vineyard cultivation practices, as well as the effect of increasingly varying climatic conditions. Even with the best crop and field management techniques employed we are often left at the whims of nature. Following the successful harvest of a crop acknowledging these unique characteristics of that particular harvest, and with its initial processing at the winery, the path to a finished wine has only just begun.

At this stage the winery is tasked with the effort to obtain higher juice yields and premier quality juice while operating under the most efficient methods. The course of production choices that are implemented are critical to achieving that goal of producing the highest volume of wine, preserving the highest product standards and enjoying reduced production costs.

The wine production process invariably depends on aggressive management and crafting of the juice during this relatively short period of production. When it really matters, the modern winemaker needs the most reliable and efficient equipment to achieve such success. To this aim the winemaker’s choice of the appropriate clarification processes plays an essential role.

It cannot be overstated that choosing the right separation technology is absolutely critical in the crafting of high quality/world-class wines. In answer to this task, wineries increasingly look to decanter centrifuges and disc stack centrifuge technology to achieve these goals. 

Whether it is utilized in pre-fermentation must clarification, post-fermentation tank bottom/lees processing or finished wine/fine clarification, it is essential for winemakers to understand the contribution that cecanter and disc stack centrifugal technology affords in the efficient and cost-efficient production of great wines. 

Decanter technology application: Must processing/pre-clarification and lees

Modern winemakers require greater economic and quality advantages in must and lees processing to assure premium juice, high yields and efficient recovery from their crop. Decanter centrifuges are the best option when liquids containing a high solids content need to be clarified. The decanter provides the winery a critical contribution in must processing/pre-fermentation clarification.

The solids content in the must results largely from the grapes' pre-treatment conditions. Crop harvesting methods as well as the grape transport greatly impact the composition of the resultant must. In regions with high temperatures (such as Australia, South Africa and California), mechanical harvesting is increasingly implemented in order to mitigate sun-exposure of laborers, address the harvesting demands of extensive land tracts, and to facilitate the picking of grapes for rapid transport to the winery. 

Mechanically harvested grapes typically have a higher solids content than manually/hand harvested grapes, due to the mechanical picking action and higher mechanical loading during transport. 

Adding to this factor, is the winery’s selection of the press system that is utilized. Pressing methods may contribute significant solids generation in the must. An example to consider is the utilization of screw presses which tend to generate considerably higher solids content than do the softer pneumatic membrane presses.

It follows, therefore, that efficient must clarification is a critical need for the further fermentation processes.

Decanter clarification offers several key advantages compared to traditional must clarification methods:

1. Increased juice quality

Decanters separate high levels of solids particles from must within seconds — significantly reducing the residual pomace or solids contact time. Extended contact with these materials is undesirable due to their high phenol content. These solids particulates will have negative impacts on the resulting juice quality, as typified when extremely long contact times result, as observed in a static sedimentation process. 

The processed must is discharged from the decanter as clarified juice, in a gentle way via an adjustable impeller. Due to this specialized discharge system, the valued liquid is discharged free of foam and under pressure. The solids are conveyed from the machine in a continuous process of elimination. These removed solids are then available for disposal, filed spread or composting.

The result of such processing efficiency is recognized in minimized solids contact time, and minimal oxygen pickup during processing. This presents an optimal process profile for must handling and quality juice production, allowing for those conditions essential to a successful fermentation.

2. Optimum clarification, high yield

The heart of the decanter is the high-speed rotating bowl complemented with the conveyor scroll, which has been specifically engineered for efficient must and wine lees clarification. 

Thanks to the adjustable impeller, the separation zone within the decanter can be optimally adjusted to obtain the cleanest possible juice product. Even in the event of fluctuating solids content present in the grape must (different kinds of grapes, harvest season, harvest method, etc.), the best clarification result can be obtained. In general, the discharged juice typically contains a desired solids content level of <2% and can be maintained during operation.

The decanter’s conveyor scroll efficiently removes those solids forming during the continuous operation of the machine. Self regulation via the PLC/control logic center of the operating torque and solids loading conditions internal to the machine provide adaptability to changing solids level conditions and provide for a stable operating condition. This supports an appropriate removal of solids and maintains consistency in the clarification of the juice

Thanks to the Simp Drive System, the differential speed of scroll and decanter bowl can be optimally adjusted, optimizing the solids residence time (pressing of the solids within the bowl conical section). The yield of the now clarified must is considerably increased by maintaining these steady operational conditions 

Decanter technology affords the winery great flexibility, supporting clarification at several stages in the wine-making process. It distinguishes itself as a valuable multi-function tool with adaptable clarification capabilities and satisfies the need for efficient solids management.

Disc stack clarifier fine clarification: Must juice/young wine/finished wine

Acknowledging the benefit to the must clarification/pre-fermentation process by the decanter, further clarification technology may be employed in the development of a high-quality wine, this is is found the disk stack clarifier. This further treatment in fine clarification will bear significant impact in preserving the full taste profile of juices, polishing of young wines and maintaining brilliance in the finished wine adding to its market value.

Due to the nature of wine solids, be they residual pomace fines present in the must processing phase or decomposed solids present in the accumulated lees, some fine particles cannot be separated from the liquid by simply using a decanter centrifuge. This is due to their low-density difference and resultant resistance to separation. This is where disc stack centrifuges are used. 

These machines operate with a significantly higher centrifugal force due to internal design and engineering refinements. In the Flottweg Disc Stack clarifier even the very fine particles can be separated to clarify juice and young wine efficiently, with clarity at or near bottle-ready condition.

Disc stack technology offers these distinct advantages:

1. Improved quality

Early clarification using disc stack centrifuges helps to remove very fine solids particles, which could have a negative impact on the taste profile of the developing wine.

As it is applied to clarification of juice prior to fermentation, these fermentations are noted to be more consistent and can be better controlled, thus optimizing the development of the wine.

2. Economic advantages

Disc stack-treated juice can be stabilized more easily and in a more economical way through its utilization. 

In the case of post-fermentation polish filtration, the filter media lifetime is extended by providing cleaner product to the polishing unit. This results in significant savings for costly filter aids. 

Separation of solids particles in the must phase reduces the amount of sulfur dioxide to be added to the wine in additional production stages, thus providing reduced potential for negatively affecting taste or coloration due to SO₂ additions.  

Advantages of centrifugal separation technology for the wine industry

Centrifuge decanters and disc stack technologies are critical to the wine industry. Additional to its contribution to those aspects of quality and volume, these continuous operation separation technologies minimize the need for hands-on attention in the cellar. This results in a reduction of labor hours and personnel required to maintain the production process. Through automatic self regulation, a decanter or disc stack centrifuge can be programmed to operate under conditions of low personnel attendance and automatic process control. 

Decanter and disk stack technology can replace expensive filtration and clarification media that presents handling and/or health hazards at the winery.

Diatomaceous Earth (DE) has been used as the standard in the wine and beer industries for a long time and has been an extremely effective and economical filtration media to facilitate liquid-solid separation. Its uniquely strong cylindrical geometry shape, high-pore volume and low resistance to flow make it a highly productive and performing filter medium. However, it is a silica-based lung irritant and is implicated as a safety consideration, and its misuse may result in chronic illness. Given the expensive nature of the media, health considerations to plant personnel and associated hazardous waste disposal costs, decanter and disk stack centrifugal separation technologies are proving to be an essential replacement to this method.

Decanter and disk stack clarification in summation 

Decanter centrifuges for must clarification offer the quick processing of must and must residues, even in the case of high solids content. The closed discharge of the clarified must reduces oxygen pick-up/oxidation. In addition, the hygienic design and complete clean-in-place (CIP) capability of decanters produce high product quality. An adjustable impeller provides optimum adjustment of the separation zone to produce continuously high yields, especially in the case of varying grape quality. 

Decanters provide a technological advantage to the traditional wine press or other clarification strategies in providing solids removal for must or lees materials. 

For the difficult fine solids removal, disc stack technology makes a positive impact on product quality, thanks to its ability in achieving optimum clarification of the juice or wines. It enjoys reduced product losses by advantage of the soft shot discharge system, and partial and total discharges reduce losses.

Both centrifuge technologies provide winemakers with a highly effective solids separation and fine solids separation technology for enhanced and efficient winemaking processes. Compact machine footprint, sturdy design, high wear resistance, low operating costs and winery specific design enhancements are critical for efficient wine processing.