Root celery, parsley, onions, carrots, asparagus and potatoes are the best vegetables to add to the soup stock. Never use celery leaves for beef soup. You may use celery leaves in potato soup, but sparingly, with chopped parsley leaves.
Vegetables, spices and salt should always be added the last hour of cooking. Strain into an earthen bowl and let cool uncovered, by so doing stock is less apt to ferment.
A cake of fat forms on the stock when cold, which excludes air and should not be removed until stock is used. To remove fat run a knife around edge of bowl and carefully remove the same. A small quantity will remain, which should be removed by passing a cloth, wrung out of hot water, around edge and over top of stock. This fat should be clarified and used for drippings. If time cannot be allowed for stock to cool before using, take off as much fat as possible with a spoon, and remove the remainder by passing tissue or any absorbent paper over the surface.
Bouillon should always be thickened with yolks of eggs, beat up with a spoon of cold water. Ordinary beef soup or tomato soup may be thickened with flour. To do this properly heat a scant spoon of soup drippings, stir in briskly a spoon of flour, and add gradually a large quantity of soup to prevent it becoming lumpy.
WHITE STOCK
Veal, turkey, chicken and fish are used.
BROWN STOCK
Follow directions given for bouillon, adding a slice of beef and browning some of the meat in the marrow from the bone.
BEET SOUP—RUSSIAN STYLE (FLEISCHIG)
Cut one large beet and one-half pound of onion in thick pieces and put in kettle with one pound of fat brisket of beef; cover with water and let cook slowly two hours; add three-fourths of a cup of sugar and a little citric acid to make it sweet and sour and let cook another hour; season and serve hot.