Q. I have a kind neighbor who recalls spinach pancakes made by his Los Angeles grandmother. He cannot find the recipe and wants to give it to his new wife, who promises to perform pancake magic. Help, please! For some reason, he feels that, as a librarian, I must know all!

A. You can prepare spinach pancakes with any pancake recipe (providing it's not too sweet). Blanch the spinach leaves and, after they cool, chop them. Mix them into the finished batter. Compensate for the water contained in the spinach by cutting back on the recipe's liquid: reduce by 1/2 cup for every 4 ounces ( 1/2 cup) of cooked spinach.

Here's a slightly more complicated recipe: SPINACH PANCAKES 2 tablespoons butter 1 medium onion, diced finely 1/2 clove garlic, minced 10-ounce bag fresh spinach, washed and chopped finely 2 eggs 1 teaspoon salt 2 teaspoons baking powder 1/2 teaspoon baking soda 1/4 teaspoon grated nutmeg 1/4 teaspoon ground black pepper 1/2 cup sour cream 2 cups all-purpose flour Clarified butter or vegetable oil

Fry onion and garlic in butter over low heat until onion is translucent. Add spinach, cover with lid and steam for 2 minutes. The spinach will shrink to a fraction of its original volume. It should not exceed 1 1/2 cups.

Beat eggs on high speed for a minute, add salt, baking powder and soda, nutmeg and black pepper. Blend 10 seconds. Add a third of the flour and the sour cream. Blend briefly. Then add another third of flour and half the cooked spinach mixture. Blend briefly. Finally, add the rest of the flour and spinach, blend and then mix on high speed for 10 seconds. The mixture should be fairly thick and smooth (except for the pieces of spinach.) Do not overbeat this batter as the pancakes will be tough. For thinner pancakes, add an extra beaten egg.

Fry on medium heat in a cast-iron skillet or griddle. As an accompaniment to a meat, these pancakes are most attractive prepared "silver dollar" size.

Q. Why are ripe olives canned in tin cans, not in glass jars as are green olives? Also, they seem to have less vinegar than the green olives. How long will black olives keep in the refrigerator after opening? Is it wise to transfer them to a sterile glass jar after they have been opened?

A. Ripe olives are canned in metal because of the rigors of the sterilization process--240 degrees for 1 hour at 10 pounds of pressure. Glass jars capable of withstanding this would be too expensive.

The tang of green olives is not vinegar but lactic acid, the end product of their fermentation in brine. Black olives are not fermented but undergo four to eight lye soaks for a period of one to five days. The lye, which is very basic (alkaline), turns them black, removes bitterness and makes their flesh neutral--neither acidic or basic.

A neutral environment is ideal for the growth of Clostridium botulinum, the bacteria which produces botulism toxin. The spores, which would otherwise germinate in the cans, must be killed by rigorous heating. This is not necessary for acidic foods like green olives: Generally, only molds and yeasts can withstand that level of acidity.

Black olives should be removed from the can after opening and stored in a covered glass or plastic container. Kept covered in their own brine and refrigerated, they will not begin to spoil for several weeks.