7 6 



SCIENCE. 



hour, somewhat of their aroma in consequence of the in- 

 fluence of the oxygen of the air, the porosity of the 

 roasted berries allowing it to penetrate easily. Liebig 

 recommended a process by which much of this pernicious 

 change can be avoided. " Strew," says he, " ovtr the 

 berries, when the roasting has been completed, and while 

 the vessel in which it has been done is still hot, some 

 powdered white or brown sugar ; half an ounce to one 

 pound of coffee is sufficient." 



The sugar melts immediately, and by well shaking, or 

 turning the roaster quickly, it spreads over all the berries, 

 and gives each one a fine glaze, impervious to the atmos- 

 phere. 



They have then a shining appearance, as though cov- 

 ered with a varnish, and in consequence lose their odor 

 entirely, which, however, returns in a high degree, as 

 soon as they are ground. 



After this operation, they are to be shaken out rapidly 

 from the roaster, and spread on a cold plate of iron, so 

 that they may cool as soon as possible. 



If the hot berries are allowed to remain heaped to- 

 gether, they begin to sweat, and when the quantity is large, 

 the heating process by the influence of the air increases 

 to such a degree, that the coffee is permanently damaged." 



In this city I have often observed that coffee is 

 roasted to too high a color, and filled into sacks too 

 quickly, before the process of cooling is complete. 



The preparation of coffee as a beverage is accomplished 

 by three processes : first, by filtration ; second, by infu- 

 sion ; and third, by boiling. 



Liebig states that filtration gives often, but not always, a 

 good cup of coffee. When pouring the boiling water over 

 the ground coffee is done slowly, the drops in passing 

 come in contact with too much air, whose oxygen works 

 a change in the aromatic particles, and often destroys 

 them entirely. 



The extraction moreover is incomplete ; instead of 20 

 to 21 per cent., the water dissolves only 1 1 to 1 5 per cent., 

 and 7 to 10 per cent, is lost. 



Infusion is accomplished by making the water boil and 

 then putting in the ground coffee, the vessel being imme- 

 diately taken off the fire and allowed to stand quietly for 

 about 10 minutes. 



This method gives a very aromatic coffee, but one con- 

 ta ning very little extract. 



Boiling is the custom in the East, and yields excellent 

 coffee. The powder is added to the water when cold, and 

 then placed over the fire and merely allowed to boil a few 

 seconds. The fine particles of coffee are drunk with the 

 beverage. It boiled long, the aromatic parts are volatil- 

 ized and the coffee is then rich in extract, but poor in 

 aroma. 



Further, Liebig gives what he calls the best method ; 

 th s I produce, not because I think the plan will make a 

 coffee acceptable to most palates, but because Liebig 

 speaks highly in its praise, and states that it is without 

 those heating properties, common to most preparations, 

 causing it to be rejected by many in delicate health. 



" My method," said Leibig,"is the union of the second 

 and third. The usual quantities of coffee and water are to 

 be retained ; a tin measure containing half an ounce of 

 green berries, when filled with roasted ones, is generally 

 sufficient for two small cups of moderate strength, or 

 one so-called breakfast cup ; one pound of green ber- 

 ries, equal to 16 ounces, yielding after roasting 24 tin 

 measures (of y z ounce each) lor 48 small cups of coffee. 



With three-fourths of the coffee to be employed, 

 (after being ground), the water is made to boil lor io or 

 15 minutes. 



The one-quarter of the coffee which has been kept 

 back, is then flung in, and the vessel immediately with- 

 drawn from the fire, covered ovei and allowed to stand 

 from five to six minutes. 



In order that the powder on the surface may fall to 

 the bottom, it is stirred around, the deposit then takes 

 place, and the coffee poured off ready for use. In order 

 to separate the dregs more completely, the coffee may 

 be passed through a clean cloth, but generally this is not 

 necessary and often prejudicial to the pure flavor of the 

 beverage. 



The first boiling gives the strength, the second addi- 

 tion the flavor. The water does not dissolve more than 

 the fourth part of the aromatic substances contained in 

 the roasted coffee. 



The beverage when ready ought to be of a brown black 

 color, somewhat like chocolate thinned with water; this 

 want of clearness in coffee thus prepared, does not come 

 from the fine grounds, but from a peculiar fat resembling 

 butter, about 12 per cent, of the amount the berries 

 contain, and which, if over roasted, is partly destroyed. 



In the other methods of making coffee, more than 

 half of the valuable parts of the berries remain in the 

 grounds, and is lost. 



"Judging," said Liebig, " as favorably of my coffee as I 

 do myself, its taste is not to be compared with that of 

 the ordinary beverage, but the good effects which my 

 coffee has on the organism should be taken into con- 

 sideration. 



Many persons who connect the idea of strength or con- 

 centration, w^th a dark color, fancy my coffee to be thin 

 and weak, but these were at once more favorably in- 

 clined, when I gave it a dark color by means of burnt 

 sugar." 



Adulteration of coffee sold in a ground state, is largely 

 carried on, especially of that sold to the poorer classes 

 — out of 34 sample-; purchased by an English analytical 

 chemist in London, 31 contained chickory, chickory 

 itself being adulterated with all manner of compounds. 



There is no falling back, says Dr. Hopall, upon tea and 

 chocolate, as these seem rather worse off than the coffee. 

 Tea is not only adulterated here, but in China, while as 

 to chocolate, the processes employed in corrupting that 

 manufacture, are described as "diabolical." It is often 

 mixed with brick dust to the amount of 10 per cent., 

 ochre 12 percent., and peroxide of iron 22 per cent., and 

 animal fats of the worst description, while the names 

 "Flake," "Rock," "Granulated," "Soluble," "Dietetic," 

 are merely employed as disguises to cover the fact that 

 they are compounds of sugar, starch and other sub- 

 stances. 



The microscope is the most effective instrument in the 

 work of detecting adulterations, the microscopic ap- 

 pearance of coffee and chickory being very distinctive, 

 while the presence of starch granules discovers the par 

 ticular cereal employed in adulterations. 



The adulteration of coffee by the addition of chicory 

 is fraudulent but harmless, chickory containing little that 

 is injurious to the system; coffee indeed is the more 

 active substance of the two ; its effects on some delicate 

 constitutions being so strongly manifested, that without 

 a violation of language, it may almost be designated a 

 weak poison. 



Sonic persons positively like the flavor of chickory, 

 others deest it; its presence, however, can be at once 

 detected by its peculiar odor, and if thrown into cold 

 water it imparts a deep tint, which coffee does not. 



In conclusion, I offer a useful receipt of Leibig's for 

 preparing coffee in a ground form for special cases, such 

 as marches and journeys, where it is inconvenient to be 

 burdened with the necessary machines for roasting and 

 grinding ; by this process its aromatic properties can be 

 preserved. 



One pound of the roasted berries is reduced to powder, 

 and immediately wetted with a syrup of sugar, obtained 

 by pouring on three ounces of sugar, two ounces of 

 water, and letting them stand a few minutes. 



When the coffee powder is thoroughly wetted with the 



