There are yeast breads that take hours, and there are tea breads that bake in minutes. And all the differences in aroma, texture, taste and keeping quality of the two can be laid to the living organism that leavens one and the chemical cluster that leavens the other.

But there are also yeast breads that are quick to make: the best of both worlds.

Forget the hours-long process of kneading, rising and punching down once again. In just 1 1/2 hours, one of these quick yeast breads can be cooling on a rack in your kitchen. The second bread takes 20 minutes to mix and knead and 20 minutes to rest before it's popped into the refrigerator (yes, refrigerator) where it awaits your whim any time during the next 24 hours. Best of all, the crust, crumb and flavor of both breads compares favorably with any two- or three-hour rising bread in your repertoire.

One main difference between the two recipes is the way the yeast is activated. In Dr. Nespor's Bread, the yeast is first dissolved in warm liquid, as in most bread recipes, but then the lactic acid bacteria in the buttermilk joins forces with the already-growing yeast for the startling burst of speed. In the refrigerator bread, the yeast is mixed dry with more than a third of the dry ingredients before the warm liquid is added. Expansion of the yeast occurs slowly in the refrigerator while you tackle other projects. Both recipes also double the usual quantity of yeast, thereby cutting down the rising time.

I've often started Dr. Nespor's Bread only to discover that I have only half a cup of buttermilk, sometimes none at all. I've used sweet milk and yogurt in varying ratios to make up the buttermilk share, or you can substitute sour milk, too, (easily made by adding one teaspoon of vinegar per quarter-cup of warm milk and letting it stand a few minutes). You can also use only one or two tablespoons of shortening, or none at all if you like a chewy bread.

A word about how to know when you've kneaded in enough flour: "Smooth, nonsticky and elastic" are the criteria most recipes use. But "smooth" compared to what? Rub your earlobe lightly between your thumb and forefinger a few times. When dough feels like that, it's smooth. "Nonsticky"? When you can hold the dough in one hand for 30 seconds and it doesn't stick to your hand when you pull it away, you've met this criterion. How about "elastic"? You can start to stretch it, of course, and watch how quickly it returns to its original shape, but I poke a floured finger into the dough. If the hole fills up quickly, I stop adding flour. (This same test can be used to determine whether the dough has risen sufficiently, only the impression in this case should remain.)

Without these tests, bread-making would be difficult since the amount of moisture absorbed by different flours varies so much: Whole-wheat flour absorbs more moisture than unbleached white flour. And because all flours will draw moisture from the air on a damp day, you may find yourself adding as much as a cup more flour than on a dry day.

For the yeast-bread taste without the hours of fussing, try one or both of these loaves.

REFRIGERATOR BREAD (Makes 2 or 3 loaves) 5 1/2 to 6 1/2 cups unbleached white flour or stone-ground whole-wheat flour

2 packages (or 2 tablespoons) active dry yeast 2 tablespoons sugar 1 tablespoon salt 4 tablespoons butter or margarine, softened 2 1/4 cups warm water (110 to 115 degrees) or 2 1/2 cups warm water if using whole-wheat flour

Mix in large bowl 2 cups flour, yeast, sugar and salt. Add butter or margarine. Add all the water gradually. Beat with electric mixer at medium speed for 2 minutes, scraping bowl occasionally. Add 1 cup flour. Beat at high speed 1 minute.

Stir in rest of flour, using wooden spoon, until dough starts to leave sides of bowl.

Knead on floured board, adding more flour as needed, for about 10 minutes. Cover with plastic wrap, then a towel, or invert bowl over dough. Let rest 15 to 20 minutes.

Punch down. Divide dough in half for two 8-by-4-inch loaves or into thirds for three 7-by-3-inch loaves. Shape portions into loaves to fit buttered pans. Place top side down to grease it, then turn loaf over so that seam side is down. Cover loosely with waxed paper, then plastic wrap. Refrigerate 2 to 24 hours.

When ready to bake, remove from refrigerator and uncover. Let stand at room temperature 10 minutes. Place in cold oven and turn oven to 350 degrees. Bake 35 minutes. Turn oven off. Remove loaves from pans and return to oven rack with door closed 15 more minutes. Remove from oven when loaves sound hollow when tops are rapped. Cool on racks.

Note: The first time you try refrigerator bread, check the rising at the end of an hour or so. The loaves may have already risen above the tops of their pans. Although the loaves should rise in the refrigerator at least 2 hours, I have sometimes baked them sooner if they seem ready to overflow. (You could also remove them, punch them down, reshape them and refrigerate them until you're ready.) At other times, the loaves seem barely to have risen level with the tops of their pans even after an interval of 24 hours.

For an alternate second step, sift 1/3 cup soy flour and 1/3 cup dry milk powder into 1 cup flour in a separate bowl. Stir in 1/4 cup wheat germ. Add this mixture as the 4th and 5th cups of flour. You will then need to stir in only about 1 1/2 cups more flour (instead of about 2 1/2 cups as in the original recipe), using wooden spoon, until dough leaves sides of bowl. You may also incorporate 1/2 cup sunflower seeds before kneading.

DR. NESPOR'S BREAD (Makes 1 or 2 loaves) 2 packages (or 2 tablespoons) active dry yeast 3/4 cup warm water (105 to 115 degrees) 1 1/4 cup buttermilk 4 1/2 to 5 1/2 cups unbleached white flour 4 tablespoons butter or margarine, softened 2 tablespoons sugar 2 teaspoons salt

Dissolve yeast in warm water in large mixing bowl. Add buttermilk, 2 1/2 cups flour, butter or margarine, sugar, and salt. Using an electric mixer, blend 30 seconds on low speed. Beat 2 minutes at medium speed. Stir in remaining flour until dough leaves sides of bowl.

Knead on a floured surface until smooth, nonsticky and elastic, about 5 minutes. Cut dough in half to use for two 7-by-3-inch loaves or leave in one piece for a 9-by-5-inch loaf. Grease pans. With a rolling pin, lightly roll the dough until the width matches the length of the pan. Roll up dough jelly-roll fashion (from the short side), seal seams, place top side down to grease top, then turn loaf over so that seam side is down.

Turn oven to 400 degrees for half a minute, then turn off. Place loaves in oven (don't cover them), close door and let them rise 40 minutes. Loaves will rise a couple of inches above top of pan.

When loaves have risen, leave in oven and turn heat on to 400 degrees. Bake about 35 minutes. Turn oven off. Remove loaves from pans. Return loaves to oven rack with door closed for 10 to 15 more minutes, to brown and to complete baking. Cool on racks.