# 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 Note 3:

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

A stable colourless solution of potassium hydroxide (or sodium hydroxide) may be prepared as follows. Bring to the boil 1 000 ml of ethanol or water with 8 g of potassium hydroxide (or sodium hydroxide) and 0,5 g of aluminium shavings and continue boiling under reflux for one hour. Distil immediately. Dissolve in the distillate the required quantity of potassium hydroxide (or sodium hydroxide). Leave for several days and decant the clear supernatant liquid from the precipitate of potassium carbonate (or sodium carbonate).

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Source: https://www.legislation.gov.uk/eur/1991/2568/annex/II/division/3/division/3.2/annotation/Note (the official version)
Page: https://openlegislation.uk/eu-regulation-1991-2568/annex-II/division-3/division-3.2/annotation/Note
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.