Make the biga. Mix water, flour, and yeast together in a large bowl. Cover the bowl and let sit in a warm place for 12-16 hours.
Time for the dough. Add the remaining water into the biga mixture and combine. In a separate bowl, combine the flour, yeast, and salt and then add it to the biga mixture. Mix with a dough hook on low speed for about two minutes. Once the dough comes together, increase the speed and allow the dough to form an elastic-like ball, about 3-4 minutes. If you do not have a dough hook, use a wooden spoon to mix the dough. Allow the mixture to form and then continue to knead the dough until it forms an elastic-like ball. Avoid adding more flour to the mixture if you can, only add it in if the mixture is looking particularity runny.
Cover the dough in the bowl and let it rise for 1 hour in a warm location. After 1 hour, deflate the dough by giving it a good punch! Poking it with a wooden spoon will work too. Cover the dough once again and let it rise for another hour.
After the rise, cover a work surface with flour and turn the dough on top if it. Cut the dough into two equal shaped rectangles, about 4x10 inches each.
Transfer the cut dough on to a piece of parchment, leave a few inches between the two pieces of dough. Cover the dough with a lightly greased piece of plastic wrap. Let the dough sit until it has doubled in size, about 2 hours.
About 15 minutes before the dough looks ready, preheat the oven to 500°. If you are using a baking stone, place the stone in the oven to heat up as well.
Take the dough and drizzle some water on top. Transfer the dough, including the parchment, to the stone. Shut the oven and lower the temperature to 425°.
Bake the ciabatta for about 20-25 minutes. The crust should be a nice golden brown when it is done. Once the crust reaches that color, turn off the oven and let the bread cool with the doors open, about 2 inches. Let cool fully and enjoy!