Book Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 edition. Excerpt: ...raw or unroasted, roasted, and ground. As might be imagined, it is in this last condition that it is liable to the chief sophistications. According to Payen, 100 parts of raw coffee contain 34 parts of cellulose, 12 of water, from 10 to 13 of fat, 15'5 of dextrine, glucose, and an organic acid, 10 of legumen, 3 of indefinite organic nitrogenous substances, and 3'5 to 5. of double caffetannate of caffeine and potash. In addition to the foregoing, Payen describes some 0'8 per cent. of free caffeine, and very small quantities of essential and aromatic oils, amounting to only 0-003 per cent. of the coffee. Payen's determination of the ash of coffee was too high, and need not be quoted. Within the last few months Mr Allen has published some determinations of the ash of coffee (vide Chemical News, vol. 25, p. 140). He finds--Percentage of ash. Specimen 1, 3-86 2, 3-95 3, 4-20 Mean '4-00 and adopting my plan of investigation, he has also determined the ratio of soluble to insoluble ash, and finds that the 4 parts of ash consist of--Soluble in water, 3-24 Insoluble, 076 400 This agrees very well with the analyses of coffee-ash which have been published, and according to which rather more than half of the entire ash consists of potash in combination with carbonic and phosphoric acids; whilst the magnesia amounts to about 8 per cent., and the lime to about 4 per cent. of the entire ash. It is said that soda and silica are absent from coffee-ash, and great stress has been laid on this circumstance. The ash of chicory (which is the main adulterant of coffee), has likewise received attention from Mr Allen. It amounts to 5"06 per cent. of the chicory, and consists of--Soluble in water, 1-74 Insoluble, 3-32 5-06 from which it may be...