Many bakeries who post on YouTube, for example Proof Bread out of Phoenix, scale and portion out their dough and set it to the side to sit for 15 or 20 minutes. After the 15 or 20 minutes rest, they go directly into the final shaping. I can see no actual shape to their preshape process.
For me, the preshape is the most confusing aspect to bread baking. I just don't know what I am doing, what shape I'm trying to achieve when preshaping?
For boules, what shape should my preshape be?
For oval loafs, what shape should my preshape be?
Preshaping can have several purposes. If the dough is slack, it can build elasticity. It can even out irregular shapes that came from dividing and scaling the dough. In a bakery setting, it can help all the loaves move through the process at a more consistent rate, since each handling step (pre-shaping then final shaping) takes less time than working up the final shape.
Right after that preshape, the dough can be too elastic to form easily into the final loaf shape. A rest lets the dough relax and get more extensible again.
Preshapes are usually a ball, but they can be made oblong if the goal is a batarde or other longish shape.
If the dough is tight and elastic at the end of bulk ferment then it can probably be shaped directly without a pre-shape. At least, that's how I do it.
TomP
Since it's a pre shape - should it have a shape? It does if you want it to. As long as the bread is what you want - it doesn't matter. Enjoy!
I always pre-shape into rounds after weighing and dividing the bulk. I let the pre-shaped pieces relax for about 20 minutes as it makes the final shaping much easier. I also look at this time as added fermentation time. I can then make all types of final shapes.
Gavin