Cocoa : its growth and culture, manufacture, and modes of preparation for the table accompanied by easy methods of analysis, whereby its purity may be ascertained / by Charles Hewett.

  • Hewett, Charles.
Date:
1862
Catalogue details

Licence: Public Domain Mark

Credit: Cocoa : its growth and culture, manufacture, and modes of preparation for the table accompanied by easy methods of analysis, whereby its purity may be ascertained / by Charles Hewett. Source: Wellcome Collection.

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    cold; if it does, starch, or flour is present. The admixture of flour, or of starch, moreover, may be readily detected by the blue colour which is imparted to the decoction after cooling, by solution of iodine. 11 Brick-dust, plaster, or other earthy matters, are detected by incinerating [burning] a given weight of the chocolate or cocoa under examination; the impurities remain among the ashes, and may be easily recognised. This adulteration is also readily detected by grating 500 grains (about ljoz.) of the chocolate in as fine a powder as possible, throwing it into about half a pint of cold water, stirring the whole briskly for about ten minutes, leaving it at rest for about two minutes, and pouring off the supernatal liquor. The earthy matter will then have subsided, and will be left as sediment. “ The presence of animal fats may be detected by the palate, for the chocolate generally has, in that case, a cheesy flavour; or, when common butter or oil has been added, it has a rancid flavour. This is quite characteristic, for butter of cocoa always remains perfectly sweet.” * If the husks have been ground up, a microscope will readily show the sharp spicuhe of which they are composed. We have added a plate shewing this dangerous adulteration. Dr. Hassall also gives the following to decide the presence of animal fat:—“If the droplets of fat or oil on the top of the cocoa be firm, shot-like, and globular, except on the upper surface, which is slightly flattened, and very small, rarely exceeding one-twelfth of an inch in diameter, then there is no doubt but that the globules in question consist of the fat or butter of cocoa. If, however, on the other hand, the globules be large, flat, or disc-like, exceed the