Sprinkle the yeast and sugar into 1/2 cup of the water in a small bowl. Leave for 5 minutes and then stir to dissolve. In a large bowl, mix the flour and salt together. Form a well in the center and pour in the dissolved yeast.
Pour half of the remaining water into the well. Mix in the flour and stir in the reserved water as needed, forming a firm and moist dough. Turn out onto a floured surface and knead until smooth and elastic, about 10 minutes. Gradually work in as much additional flour as possible while comfortably kneading to form a stiff and firm dough.
Put the dough in a lightly oiled bowl, turning the dough to coat it. Cover with a towel and let rise for 1 hour or until doubled in size. Punch down and let the dough rest 10 minutes.
Divide the dough into 8 pieces. Shape each piece into a ball – cup between your hands and press the bottoms together between your palms. Press down to get rid of air bubbles and roll the dough between your palm and the work surface to form a smooth ball. Coat a finger in flour and press it through each ball to form a ring.
Work the rest of your fingers into the hole, stretching the ring and widening the hole to about 1/3 of the bagel’s diameter. Place the bagels on a lightly oiled baking sheet and cover with a damp towel. Let rest for 10 minutes and preheat the oven to 425 degrees F.
Bring a large pan of water to a boil and then reduce to a simmer. Use a perforated skimmer to lowel the bagels into the water in batches of 2-3. Boil, uncovered, until they rise to the surface, about 1 minute. Turn them over once. Then remove from the pan, letting the water drain, and transfer to a lightly oiled baking sheet. Bake 20 minutes, until golden, and cool on a wire rack.