In a 5- to 6-qt bowl or stand mixer, whisk together the flour, yeast, salt and sugar.
Add the lukewarm water — lukewarm water (100ºF) will allow the dough to rise to the right point for storage in about 2 hours.
Mix with a spoon or spatula or paddle attachment of mixer until mixture is very smooth — this will take about a minute of good stirring. Kneading is unnecessary. Transfer mixture to lidded (not airtight) food container.
Cover with a lid that fits well to the container but can be cracked open so it’s not completely airtight. Plastic wrap is fine, too. Allow the mixture to rise at room temperature about 2 hours; then refrigerate it and use over the next 10 days. You can use a portion of the dough any time after the 2-hr rise. Fully refrigerated wet dough is less sticky and easier to work with than dough at room temperature, but whatever you do, do not punch down the dough — this is unnecessary with gluten-free bread baking.
On baking day: pull off a 1-lb (grapefruit-size) piece of dough, then place it on a pizza peel prepared with plenty of cornmeal or parchment paper. Gently press the dough into a ball and use wet fingers to smooth the surface. Allow to rest at room temperature for 60 minutes loosely covered with plastic wrap or a roomy overturned bowl. The dough will not look as though it has risen much after the 60 minutes — this is normal.
Preheat a baking stone or Baking Steel near the middle of your oven set at 450ºF for at least 30 minutes. Alternatively, preheat a lidded Dutch oven for 45 minutes at 450ºF. If you are using the stone or Steel, place an empty metal broiler tray for holding water on the shelf below the stone or Steel.
Dust the top of the dough liberally with flour. Slash a ½-inch-deep cross or scallop using a wet serrated bread knife.
Shimmy the loaf onto the preheated stone. Alternatively, use the piece of parchment paper as handles and carefully lower the dough-topped parchment paper into the preheated pot. Cover and place in the oven. Quickly and carefully pour 1 cup of hot water from the tap into the metal broiler tray and close the oven door to trap the steam. If you used parchment paper on the steel or Stone, remove it after 20 minutes. Bake loaf for 45 minutes. If you are using the preheated vessel, remove the lid after 30 minutes, and bake for 15 minutes longer uncovered or until the crust is richly browned. Allow bread to cool completely, about 2 hours, on a wire rack.
Store remaining dough in the refrigerator in your lidded or loosely plastic-wrapped container and use it over the next 10 days.