Some confusion may exist at times in the use of the word "Coffee," which is applied alike both to the bean roasted or unroasted and also to the decoction thereof. Both green and roasted coffee contain large quantities of soluble material, the green bean, as has already been stated, yielding a larger percentage of soluble material than the roasted article. This is probably due to the fact that the sugar is converted not only into caramel but into lower forms of decomposition which are more or less insoluble. The extracted matter from the roasted coffee is determined in two ways: one, a short extractive period of two or three minutes; and second, a complete extractive period. From 3 to 4 percent more extracted matter will be obtained by complete extraction than is obtained by the ordinary method of making coffee.

For a general description it may be assumed that fully 20 percent of the coffee used will appear in the extract when made in the ordinary way. There are two ordinary methods of making coffee decoction. One is boiling for a short period with the proper amount of water, and the other consists in passing the boiling water over the finely powdered coffee, thus securing its soluble constitutents by percolation. This latter method makes a finer flavored coffee to most tastes but not so strong for the amount of coffee used as the three- or four-minute boiling. In the United States, at least, most people prefer a perfectly limpid, clear coffee without any sediment. This is obtained either by mixing white of egg with the coffee before extraction, or by enclosing the coffee in a linen bag or a very fine gauze which prevents the fine particles of coffee from passing into the decoction. There is little to say regarding the preference between the two methods of extraction. Where economy is desired and at the same time a coffee which is of fine quality, the boiling method is preferred. Where larger quantities of coffee can be used for a given amount, the percolation method is to be preferred.