Place yeast in large bowl; pour 1/4 cup warm water over yeast. Stir gently and let sit a few minutes until thoroughly dissolved. Add oil, sugar, salt, tarragon, warm water and 4 cups of the flour. Beat until thoroughly combined and smooth. Add remaining flour to make a moderately stiff dough. Knead 10 minutes, until smooth and elastic. Place in greased bowl; cover and allow to rise until double in volume. Turn dough out on lightly floured surface; punch down. Divide dough into two portions. Form each half into an 8-inch long loaf. Place in two greased 9x4-inch loaf pans. If desired, place oval loaves on a greased baking sheet. Cover and let rise until almost double. Bake at 400 degrees for 10 minutes. Reduce heat to 350 degrees and continue baking 25 minutes, until nicely browned and done. Bread will sound hollow when tapped. Remove bread from pan and cool on wire racks. Makes 2 loaves.