Subject: 31. How do I get that lofty loaf?
Getting the lofty loaf starts way back with kneading and getting the correct consistency (percent hydration). This is easier to do when you weigh rather than volume-measure ingredients. Next, your fermentation stage (after kneading, before dividing and rounding) should not be excessively long. Sourdoughs do not have to double in bulk in fermentation, as much of their flavor and microbiological vigor is carried from the prefermentation stages-- from the sponge or leaven you have made from your active starter.
The next most critical determinant of a lofty loaf is shaping. Some people shape the finished loaf just after they have divided the dough, which works well for plastic doughs, like high percentage rye flour doughs. But for elastic and extensible doughs, like well hydrated, well kneaded wheat doughs, it is better to divide, round the loaves (pre-shape, pre-stretch the dough structure) and let them rest about 10 minutes on the bench. Then when you finally shape them (means just that, not just making a big lump) you will get the necessary gluten tension to provide the lofty loaf you seek.
If you are in doubt, underproofing is better than overproofing, Of course perfect proofing is best. But any well shaped, well proofed loaf should be able to take slashing by a very sharp knife-- 'been doin' it for years.
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