1) Mix starter ingredients together and let sit about 14 hours at room temperature.
2) Combine yeast and water for dough and then add starter.
3) Stir in flour. Once you form a dough ball, you will either want to mix this with your dough hook or if you are old school (poor) like me, you want to knead it until you have a smooth ball of dough that passes the windowpane test. For me this was about 15 minutes of serious kneading.
4) Lightly oil the dough and let it rise for 3 hours. After one hour, deflate it and give it a turn. Then let it rise for 2 more hours.
5) Cut the dough into thirds. I recommend weighing it and not just going by sight.
6) Take each of your thirds and flatten it out into about an 8 by 5 inch rectangle. Then fold it over but leave about 1/2 an inch on the bottom. Where the two halves meet, press lightly to seal it. Flatten it out again and fold it one more time.
7) Roll up the baguette, sealing the edge and lightly roll your baguette back and forth until you have your 18 inch baguette. Proof the baguettes for 30 minutes in a few towels dusted with flour.
8) Put baguettes on a baking sheet and spritz with warm water.
9) Score baguettes on the diagonal with a bread knife (serrated knife).
10) Bake for 25-30 minutes at 450. Check them at 20 minutes though. Cool them immediately on a rack. Let them cool well before slicing and serving.