# Commission Regulation (EEC) No 2568/91 of 11 July 1991 on the characteristics of olive oil and olive-residue oil and on the relevant methods of analysis, Division 2.7: Second extraction

Extent: E+W+S+N.I.

Tip the contents of the thimble into the micro-grinder and grind as finely as possible. Return the ground mixture to the thimble without loss and place it back in the extraction apparatus.
Continue the extraction for a further two hours using the same round-bottomed flask containing the initial extract.
The resultant solution in the extraction flask must be clear. If not, filter it through a filter paper and wash the original flask and the filter paper several times with hexane. Collect the filtrate and the washing solvent in a second round-bottomed flask which has been dried and tared to the nearest 1 mg.

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Source: https://www.legislation.gov.uk/eur/1991/2568/annex/XV/division/2/division/2.7 (the official version)
Page: https://openlegislation.uk/eu-regulation-1991-2568/annex-XV/division-2/division-2.7
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.