The ingredients must be very well mixed otherwise, the xanthan gum or psyllium will not be evenly distributed and your loaves will be inconsistent. 

* Do not substitute with sweet white rice flour.

** Do not substitute with potato flour.

If you’re measuring by U.S. cup-measures, be sure to pack the flour tightly into the cup, as if you were measuring brown sugar.

In a 5 to 6-quart 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 the paddle attachment of mixer until mixture is very smooth, for about one minute. Alternatively, using a spoon or spatula, mix well by hand for one to two minutes. Kneading is not necessary. 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-hour 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-pound (grapefruit-size) piece of dough, then place it on a pizza peel prepared with plenty of cornmeal or on a large piece of parchment paper. Gently press the dough into an elongated oval of a 3/4-inch thickness measuring about 9-inches by 5-inches.  Use wet fingers to smooth the surface. Dust the top with rice flour and cover loosely with plastic wrap or an overturned bowl.  

Allow it to rest at room temperature for 30 minutes. The dough will not look as though it has risen much after the 30 minutes — this is normal.  Remove the plastic wrap and dust with more flour if most of it has come off or has been absorbed.

While the dough is resting, preheat a baking stone or baking steel near the middle of your oven set at 450ºF for 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.

Shimmy the loaf onto the preheated stone. 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 are using parchment paper on the steel or stone, remove it after 20 minutes. Bake loaf for a total of 35 minutes. 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. No need for a steam bath with the dutch oven. If you are using the preheated vessel, remove the lid after 30 minutes, and bake for 5 minutes longer uncovered or until the crust is richly browned. 

Allow bread to cool completely, about 2 hours, on a wire rack.  Gluten-free bread needs a full two hours of cooling to set completely.

Store remaining dough in the refrigerator in your lidded or loosely plastic-wrapped container and use it over the next 10 days. If your container isn't vented, allow gasses to escape by leaving the cover open a crack for the first couple of days in the fridge. After that, it can be closed.