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When wine has a thirst for research. © FOTOLIA, Fotolia

When wine has a thirst for research

Dynamic grape crushing: a new technological concept in winemaking

Developed by the company PELLENC in partnership with INRA, this new crusher operates by splitting open grapes rather than crushing them.  Trials carried out at the INRA Pech Rouge Experimental Unit (Gruissan, Aude) have demonstrated the advantages of this process which achieves better yields and an optimum extraction of total polyphenols after maceration.

Updated on 12/30/2013
Published on 12/26/2013

Splitting open grapes but without touching the pips and any plant debris (leaves or stems, etc.) is the difficult mission of a successful crushing operation.  Indeed, it is only contact between the juice and the yeasts naturally present on grape skins that guarantees the optimum initiation of alcoholic fermentation.

Traditionally, a crusher comprises a hopper containing the grapes, under which two finely notched rollers turn in order to split the berries open.  The art of crushing therefore consists in adapting the gap between the rollers to the size of grapes from each variety.

PELLENC has developed a crusher that is capable of operating continuously according to a new principle: the harvest is poured into a hopper that feeds a wheel which, once it starts turning, throws the grapes against the wall of the crusher, thus splitting them open.  The velocity of the wheel can be adjusted, and the opened berries fall by gravity under the crusher.  The result is that crushing no longer depends on the size of grapes but also on their ripeness, so that neither unripe green berries, nor pips, nor any other plant waste, are crushed.  Crushing capacities can then reach up to 24 tons an hour, without any loss of quality.

Pinot noir grapes. © INRA, WEBER Jean
Pinot noir grapes © INRA, WEBER Jean
Working in partnership with PELLENC, INRA has evaluated the performance of this crusher on destemmed  grapes for red wine production.  The berries thus obtained were much more open, and larger quantities of pulp and juice were extracted, enabling an increase in the exchange surfaces between the skins and the juice during the maceration step.  Furthermore, and unlike roller crushers - the principle of which is to press down on the berries in order to eject the pulp - this new crusher opens the berries and thus exposes a much larger contact surface between the skins and the juice.  This specificity means a better destructuring of the impermeable skin of the grapes during maceration and an increase in the release of polyphenols, which in turn leads to a stronger purple and darker wine colour, as well as the more rapid stabilisation of its colour in the bottle during ageing.
In 2013, this crusher moved to industrial production under the brand name of Extractiv’.

Depending on the technology employed, it is thus possible to better drive the extraction of polyphenolic compounds during the maceration stage, with major consequences for the sensory qualities of the finished product.  It thus constitutes a basic tool for precision oenology.

Contact(s)
Scientific contact(s):

  • Jean-Michel SALMON Pech Rouge Experimental Unit, 11430 GRUISSAN
Associated Division(s):
Science for Food and Bioproduct Engineering

FOR FURTHER INFORMATION

  • Bellenc R., Bes M., Samson A., Salmon J.M. (2011). Procédé et dispositif de  foulage dynamique des fruits. French patent filed on 30 August 2011, EP no. 1102629.