Choosing the best baking stone is usually a matter of understanding the differences between your options and having at least some idea of how you want to use the product. Baking stones come in a wide variety of sizes, shapes, and styles. The most complex baking stones are designed to be permanent oven fixtures and are usually only installed on commercial ovens. Most of the more commonly available stones are much smaller and are meant to handle a single loaf of bread or but one pizza. Prices, as well as material composition and heat distribution characteristics, tend to vary, as well.
The first thing you should discern is why you want a baking stone. If your main goal is to make pizzas that taste like they have just come out of a traditional Mediterranean stone oven, a specifically pizza stone may be for you. Specifically pizza baking stones are usually round, and are often designed to support the shape of the dough as it rises and browns.
Pizza is only one of the things that can be made with a baking stone, however. Virtually any baked good can be cooked on a stone instead of, or in addition to, a more modern pan. Many cooks praise the ability of the baking stone to seal in moisture and produce a crispy, perfectly golden crust not easily attained in metal or glass bake ware. Stones are often optimized for certain temperatures and crust conditions.
Baking stones primarily intended for free-formed loaves are typically square or rectangular in shape. Of course, pizza can be baked on a square stone, and bread cooked on a circle rarely turns out any different on a circular slab. Most of the difference between the stones is owning to their composition and thickness, not their shape.
In general, the thicker the stone, the more likely it is that your baked goods will carry the taste of a traditional brick oven. A baking stone works by absorbing the heat from your oven, then evenly distributing it directly over the surface of the rising dough. Thick oven baking stones can capture more heat than thin ones, which lends more of the even browning so prized by brick oven enthusiasts.
A thick stone that is made of a low quality composite stone is an exception. The final thing to look for as you consider different bread stone options is the integrity of the stone. A thick baking stone at a remarkably low cost may indicate low quality. The best stones are made of high-grade ceramic and have been kiln fired and certified to conduct temperatures up to a certain level.
Finally, you will need to make sure that your chosen stone will fit inside of your oven. In most cases, you will need at least an inch (about 2.5 cm) on each side of the stone to ensure proper air flow. This is particularly true if your oven is gas powered. Stones should never cause baked goods to come into close contact with your oven’s heating elements, either.