ROASTING is necessary to develop the aroma and goodness of coffee. This delicate operation changes its chemical composition and develops the caffeine and volatile oil. If roasted too little the coffee retains a raw taste; if too much, a part is changed to charcoal and much aroma lost. The outside may be burned and the inside left raw, or some grains may be half raw and others burned. Coffee loses in weight from 15 to 20 and even 25 per cent., and gains in bulk from 30 to 60 per cent., according as it is roasted to a reddish, chestnut, or dark brown. The best roasting is that which reduces the weight about sixteen per cent., or to a light chestnut brown.
Tea yields, weight for weight, twice as much caffeine (or theine) as coffee; but as we use more in weight of the latter, a cup of coffee contains about as much caffeine as a cup of tea. The composition of roasted coffee and the tea leaf are given as follows, although the proportions are variable:
One pound of the properly roasted bean or berry should make 55 or 60 cups of good coffee. Coffee may be made too bitter, but it is impossible to make it too fragrant. Coffee is much the best when freshly ground. The French and many Americans merely steep or infuse their coffee at a temperature just below the boiling point, claiming that boiling dissipates the aroma; others bring it only to a boil; while others still, hold that boiling it a little is more economical, as giving an increased quantity of the soluble, exhilarating and bitter principles. Soft water is best for coffee, and coffee is better cold than warmed over, as it then loses its fragrance.
Rye, beans, peas, acorns, carrots, turnips, dandelion root, burned bread, and many similar substances have at times been used as substitutes or adulterants for coffee. But as none of them contain caffeine or the volatile aromatic oil, they cannot serve the same physiological principle. Ground coffee is extensively adulterated, and mainly with the much cheaper
Roasting develops in this root an empyreumatic, volatile oil which exercises upon the system some of the nerve-soothing, hunger-staying effects of tea and coffee. A little chicory gives as dark a color and as bitter a taste as a great deal of coffee. It is not unwholesome unless taken in excess, when its effects are bad. It is a poor substitute for coffee, but some people seem actually to prefer coffee which contains chicory.