xamination is usually sufficient to show the presence of
excessive amounts of black and blighted coffee beans, coffee hulls,
stones, and other foreign matter. These can be separated by hand-picking
and determined gravi-metrically.

2. _Coloring Matters--Tentative_

Shake vigorously 100 grams or more of the sample with cold water or 70
percent alcohol by volume. Strain through a coarse sieve and allow to
settle. Identify soluble colors in the solution and insoluble pigments
in the sediment.

ROASTED COFFEE

3. _Macroscopic Examination--Tentative_

Artificial coffee beans are apparent from their exact regularity of
form. Roasted legumes and lumps of chicory, when present in whole
roasted coffee, can be picked out and identified microscopically. In the
case of ground coffee, sprinkle some of the sample on cold water and
stir lightly. Fragments of pure coffee, if not over-roasted, will float;
while fragments of chicory, legumes, cereals, etc., will sink
immediately, chicory coloring the water a decided brown. In all cases
identify the particles that sink by microscopical examination.

4. _Preparation of Sample--Official_

Grind the sample to pass through a sieve having holes 0.5 mm. in
diameter and preserve in a tightly stoppered bottle.

5. _Moisture--Tentative_

Dry 5 grams of the sample at 105 deg.--110 deg. C. for 5 hours and
subsequent periods of an hour each until constant weight is obtained. The
same procedure may be used, drying _in vacuo_ at the temperature of boiling
water. In the case of whole coffee, grind rapidly to a coarse powder and
weigh at once portions for the determination without sifting and without
unnecessary exposure to the air.

6. _Soluble Solids--Tentative_

Place 4 grams of the sample in a 200-cc. flask, add water to the mark,
and allow the mass to infuse for eight hours, with occasional shaking;
let stand 16 hours longer without shaking, filter, evaporate 50 cc. of
filtrate to dryness in a flat-bottomed dish, dry at 100 deg. C., cool and
weigh.

7. _Ash--Official_

Char a quantity of the substance, representing about 2 grams of the dry
material, and burn until free of carbon at a low heat, not to exceed
dull redness. If a carbon-free ash can not be obtained in this manner,
exhaust the charred mass with hot water, collect the insoluble residue
on a filter, burn till the ash is white or nearly so, and then add the
filtrate to the ash and evaporate to dryness. Heat to low redness