To make the starter: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Combine all of the ingredients and mix until uniform. Cover and let rest at cool room temperature overnight., To make the dough: Combine the starter with the remaining ingredients to form a stiff dough. Knead by hand for 12 minutes, or in a mixer for 9 minutes. The dough will be smooth and elastic, and should not spread much when you stop kneading., Place the dough in a lightly greased bowl, and let rise until puffy but not necessarily doubled in bulk, 1 to 1 1/2 hours. After this rise, transfer the dough to a clean work surface, gently deflating it in the process., To shape and bake the bagels: Divide the dough into eight pieces for large bagels or sixteen pieces for smaller (3 1/2") bagels., Roll each piece into a ball, cover, and let rest for 30 minutes. They'll puff up very slightly., Poke a hole through the center of each ball, then twirl it around on your finger until the hole is 1 1/2" in diameter., Place the shaped bagels on a lightly greased or parchment-lined baking sheet, and allow to rise, covered, for about 45 minutes., While the bagels are rising, place a steamer rack in a wide pan or canning kettle. Put 1" to 2" of water in the bottom and bring it to a simmer., Preheat the oven to 400°F., Place as many bagels as will fit on the steamer with 3/4" of space between them. Cover the pan and steam the bagels for 90 seconds., Using a spatula and your fingers, gently remove the bagels from the steam and return them to the baking sheets. Repeat until all of the bagels are steamed., If you wish to top the bagels with seeds or other toppings, brush with beaten egg wash, and apply the seeds of your choice., Bake the bagels for 20 to 25 minutes, or until deep golden brown., Remove the bagels from the oven, and let cool on a rack., Store in a paper bag on the counter for one day; or slice and freeze for up to two months for longer storage.