Two Questions - Hydration and Bulk Fermentation

Hi slowriser!

1) it is not so much hydration as dough consistency that matters. Some goodies require soft dough, others - stiff dough. It affects everything, how it ferments, how fluffy it gets, how it bakes and how it tastes when you bite and chew it.

Baguette dough is usually baked until it loses anywhere from 25% to 50% of its original weight, a lot of water is lost as it bakes, water evaporates, so it is a bit moister originally. Pizzas are usually baked quickly and have moist toppings so the dough stays moist and doesn't lose as much water as it bakes, therefore it doesn't need as much water initially inside it.

2) the point of bulk fermentation is fermentation. In other words, it makes freshly mixed dough into a mature, ripe, ready to use dough that is tasty and fragrant and could be used in the kitchen or in a bakery for any other purpose: to sell it as 'bread dough' or 'pizza dough' to the customers, to fry it, to steam it, to boil it, to bake it and then to serve it and to eat it. 

If you make rolls or pitas you can mix 100 portions of dough, each from 30 g of flour and 20g of water and let them 100 portions ferment until ready to be used and use each to prepare one roll or one pita. As you wish. It doesn't matter. Or you can mix 3000g of flour and 2000g of water into dough and let it ferment until ripe and mature, fragrant and tastes delicious and divide it into 100 portions and bake them into pitas or rolls. As you wish. 

If you look how bread machine works, for example, it mixes enough dough exactly for one loaf of bread or for one roll or one pita and once dough is ready, well fermented, it shapes it into a ball and gives you a signal. After that you can continue with the bread machine program and let it bake it into a loaf or take it out and do with it whatever you want at home: freeze it, refrigerate it for future use as needed, or bake it, fry it, etc. into whatever you want right away. 

best wishes, 

m. 

As always Mariana’s answer is comprehensive!  I’ll just add with baguettes you need a dough that is extensible enough to elongate to the final shape but not too wet to make the shaping too difficult.  If the hydration is too low, then the dough will be harder to extend to the wanted length.  If it is too wet, it might be more challenging to deal with during shaping.

Benny

If I can add to these already great answers, there is also the mechanical actions and physical shape of the dough to consider, as well as the composition and dispersion of ingresient.

The mechanical and practical side

As your dough ferments, two competing forces are at play. The fermentation lowers the pH of the dough which works to strengthen the gluten network. However, the various enzymes are also hard at work weakening the dough. The positive of this action is that it generates extensibility, however you will notice that, as you leave a mass of dough to ferment - whether in bulk or divided - the dough will tend to spread out and 'relax'. This spreading increases as time goes on, thus, the longer a dough is fermenting, the more it is spreading.

As a purely practical matter, dividing your dough early means you have multiple masses of dough, each spreading and thus each requiring its own dedicated space to relax and ferment. This is annoying enough in a home setting; it would be at best unweildy in a commercial bakery but likely nearly impossible to manage and uneccesarily increase the work required.

At the simplest level, the least inefficient way to do this would be to have the individually-portioned doughs fermenting directly on a bench, covered. If you are a home baker, whipping up a half-dozen dinner rolls for the family, that's fairly do-able but, again, in a commercial setting - where you are making an order of magnitude more rolls - it's just not feasible.

Now, ff you're making two loaves, that's fine and might even be a good thing, as you can put one batch in the fridge sooner or experiment with different add-ins of processes. For pita or rolls, I am going to assume at least 4 and likely 6 or more and, further, that you are likely after uniform results throughout, so the potential benefits of individual fermentation is likely not there for that situation, even if the negatives are manageable.

Once they've fermented, you then need to shape the dough pieces - most usually with an initial pre-shape and then a final shaping, where the nearly-ready dough pieces are placed in their final proofing forms.

Let's say you're making a dozen small dinner rolls with commercial yeast with a quick process (~3 hours' fermentation).

When performing a standard bulk-ferment, it all goes in one container and is tucked away for a few hours. Once, say, 2 hours is up, it's tipped out in one mass, scaled into 12 pieces and each piece is pre-shaped and left for 30 mins on the bench.

After 30 mins, those balls will have spread out a little and so they undergo another, final shaping and are placed in their proofing forms - whether thats a tray or pan or couche or banneton to whatever. This final shaping will put a tight skin on the dough that, in combination with the proofing form, will encourage the dough to rise in the desired direction (usually up!).

This series of relaxations that occur after each step is one good reason why it just causes extra pain to divide the dough at the start and ferment each portion individually.

Now, all this assumes that you are fully- developing your dough from at the start (e.g. in a mixer). If you are planning on performing any strengthening steps while the ferment is in process - most typically in the form of 'folds', if you have already divided your dough, thats multiplying your work for no real benefit. A bulk ferment allows you to perform one set of folds on one mass of dough.

The dispersion of ingredients.

To wrap this up quickly (as I am really getting tired,) when you mix your dough, you start with a very small amount of yeast that is hopefully dispersed evenly. During the fermentation, this small amount of yeast reproduces and multiples through the dough.

If you mix your portions one-by one, you can be sure there is the same quantity of yeast in each portion; if you mix it as one and then divide straight away, there is a much higher liklihood that the portions will contain different quantities of yeast, which may affect fermentation time, giving inconsistent results.

d.