Nestec S.a.

Klaus Schlecht

Olaf Wehrspann

Geoffrey Margolis

Valerie Leloup

Elke Gerhard-Rieben

Claude Rene Lebet

Alain Mercier

A process for the counter-current extraction of soluble coffee solids. Soluble coffee solids are extracted from roast and ground coffee in a first extraction stage using a primary extraction liquid at a temperature of 80.degree. C. to 160.degree. C. Then soluble coffee solids are extracted from the partially extracted grounds in a second extraction stage using a secondary extraction liquid at a temperature of 160.degree. C. to 190.degree. C., the coffee grounds having at least 25% by weight of soluble coffee solids extracted from them. The coffee grounds obtained from the second extraction stage are drained and thermally hydrolyzed in a hydrolysis stage at a temperature of 160.degree. C. to 220.degree. C. for 1 to 15 minutes. Soluble coffee solids are extracted from the hydrolyzed coffee grounds in a third extraction stage using a tertiary extraction liquid at a temperature of 170.degree. C. to 195.degree. C. to provide extracted coffee grounds and a hydrolyzed coffee extract.

Coffee extraction process

Roast and ground coffee is extracted by a split extraction process to obtain an extract from an atmospheric stage and an extract from a pressure stage. The extract produced by the atmospheric stage is evaporatively concentrated to a dry matter content of above 35% by weight, and the evaporation vapors produced during evaporative concentration are condensed and concentrated. The extract produced by the pressure stage also is evaporatively concentrated to increase its dry matter concentration to a dry matter concentration below 25% by weight. The two concentrated extracts then are mixed, and that mixture is evaporatively concentrated to a dry matter concentration of more than 40% by weight. The condensed and concentrated vapors obtained from evaporative concentration of the atmospheric stage are introduced into the evaporatively concentrated mixture or into a powder obtained from the concentrated mixture.

Treatment of extracts obtained by split extraction of coffee

Coffee oil is separated from a filtered extract produced by counter-current extraction and the separated oil is incorporated into soluble coffee powder.

Obtention and use of coffee oil

To reduce insoluble solids contained in a coffee extract obtained from a countercurrent extraction process, the percolation rate of extraction liquid passing through at least one extraction cell, which is positioned intermediately in the countercurrent cell series between extraction cells containing the least extracted coffee material and the most extracted coffee material, is reduced. The flow of extraction liquid may be increased through an extraction cell in the series downstream from the at least one cell in which the percolation rate is reduced.

Countercurrent extraction of coffee

Two flash evaporation steps are incorporated into a countercurrent extraction process employed to extract coffee. One flash evaporation step is performed upon a first extract obtained from an extraction cell having a temperature of above 150.degree. C., the flash evaporation being performed at a temperature reduced from 150.degree. C. The second flash evaporation step is performed upon a second extract obtained from an extraction cell positioned at least one cell downstream in the series from the cell from which the first extract was obtained, the second flash evaporation being carried out at a temperature higher than the temperature of the first flash evaporation and the product thereof being introduced to a further downstream extraction cell.

Process for countercurrent extraction of coffee

Extraction yield of coffee extracted in a countercurrent extraction system is increased by separating sludge by centrifugation from coffee extract obtained from the system and introducing the sludge into at least one extraction cell of the system so that the sludge may be hydrolyzed during the extraction of the coffee.

Process for increasing coffee extraction yield

Process for extracting roasted and ground coffee characterized in that the coffee, having an average particle size not exceeding 2.0 mm, is wetted in the absence of air with at least twice its weight of an aqueous liquid, and the wetted coffee is transferred, in the absence of air, to an extractor where it is extracted with an aqueous liquid at a temperature of at least 100.degree. C.

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Orbe, Switzerland

Klaus Schlecht