In baking bread we usually consider the water content of a recipe as a percentage of the over-all amount of flour used. A high water content, or high-hydration, dough is usually 65% plus. So what does it mean both in terms of making the bread and the final result?
The dough will be wetter and harder to handle. Kneading the dough can be very difficult and, therefore, we don’t do it. Instead we use the folding method for developing the gluten that will provide the structure of the loaf. Folding takes more time.
When it comes to weighing the dough (scaling) and shaping, high-hydration takes courage and a bit of technique. You can have quite a pile of gloop on the bench but the resulting bread should have more of the large bubbles of air in the crumb.