One of the principal objections to coffee drinking is the tendency which is produced in many instances to create caffein dyspepsia or poisoning. It cannot be doubted that the excessive use of coffee, or its too frequent use, or its use in infancy or childhood, are all attended with some danger and frequently with serious and permanent, injury. The chief objectionable ingredient of the coffee bean is the alkaloid, caffein. The average quantity of caffein in the raw bean is a little over 1 percent. The percentage quantity in the roasted bean is somewhat increased, because of the loss of moisture and other volatile substances during the process of roasting. The roasted coffee will contain perhaps an average of 1.2 percent of caffein, whereas the unroasted will be a little less than 1.1 percent.

1 Good Housekeeping, October, 1917, page 144.

Method Of Extraction

Many attempts have been made, and by various agents, to remove practically the whole of the caffein from the coffee bean. The coffee bean, as is well known, is an extremely resistant substance; it is very tough; it is almost impossible to powder it or disintegrate it by pounding, and hence it is quite impracticable to attempt to grind or reduce to a powder the green coffee bean before extraction. If this could take place, the actual labor of extracting the caffein would be very much decreased, and the degree of extraction increased. Since this, however, is not practicable in commercial transactions, other methods of proceeding have been studied and adopted to a greater or less extent. The more common one is to soften the bean first by subjecting it to the action of steam under pressure. This method of procedure softens the bean to a greater or less extent and opens up its pores so that an extracting medium can penetrate into the interior of the bean. Any of the common solvents of caffein may be used, but benzol, or trichlorethylene are generally employed. These bodies have very little effect upon the other constituents of the bean. After the extraction has been completed, any residue of the solvent remaining in the bean may be expelled by a re-application of the superheated steam, or by distilling in a current of steam.

Degree Of Extraction

The quantity of caffein which is left in coffee after it is thoroughly treated in the manner above described, may be placed at about 0.2 of 1 percent. In some instances, almost complete extraction is secured, as for instance 0.02 of 1 percent, while in others a comparatively large quantity, amounting to over 0.25 of 1 percent may be left. It is evident that the phrase caffeinless cannot be properly applied to a body which has been treated in this way, because to be caffeinless all of the caffein must have been abstracted.