In all the trials a higher yield of quality free-run juice was obtained when compared with standard processes. In general, the yield obtained from the decanter (only one fraction instead of two as in standard processing) exceeded 700 ℓ/tonne for dry-land grapes and 800 ℓ/tonne for irrigated vines. The free-run juice yield for standard processing was between 350 and 550 ℓ/tonne of grapes crushed, depending on the cultivar and the cellar infrastructure.
The differences in degrees Balling, TA, pH and YAN (yeast assimilable nitrogen) between normal and decanter juice were insignificant. The decanter did not alter the juice composition for these parameters. Juice processed with the decanter had lower potassium and total phenol concentrations than standard processing. However, higher potassium and total phenol concentrations were observed in juice kept for longer than 30 minutes and at higher temperatures for both decanter and control juice.
The wines made from the first decanter trials done at Groote Post with Sauvignon Blanc and Chardonnay grapes were used for the same blends as the standard processed wine. No negative quality effects were thus observed.
The 2013 trials with Sauvignon Blanc at Boschendal were judged by 14 experienced winemakers using the triangular taste method and ranking:
- The judges were unable, with the triangular tasting, to indicate significant differences between the Hiller decanter and the control wines.
- The ranking results of the wines were insignificant, with no preferred wine.
Wines (MCC base) were made from grapes processed at Graham Beck in Robertson:
- On Chardonnay base wines the judges indicated with the triangular tests a slight difference between the Hiller decanter and the control wines.
- The Hiller wines were preferred and showed more citrus and fresh fruit than the control Chardonnay wines.
- The Pinot Noir MCC base wine from the Hiller decanter had less red colour than the control wine. The MCC wine made from decanter processing was as good as the control wine.
The way forward
Decanter technology allows for rapid juice processing in cellars, without the need for large and expensive equipment such as drainers and presses. The combination of high quality and high yield makes the system attractive for quality and bulk-wine producers alike.
We thank the following winemakers that helped with the development of the Hiller grape process by providing their cellar facilities and grapes:
- Lukas Wentzel, Groote Post.
- Len Knoetze and Renier van Greunen, Namaqua Wines.
- Abé Beukes, Darling Cellars.
- Kallie van Niekerk and Kobus Gerber, Distell.
- JC Bekker, Lizelle Gerber and Bertho van der Westhuizen, Boschendal.
- Bowen Botha and his team and Francois Weich, Robertson Wines.
- Pieter Ferreira, Graham Beck Wines.
For further information, contact Hans Perabo or Brett Rightford at firstname.lastname@example.org.