When done correctly, stretching and folding sourdough will strengthen the gluten and gently incorporate air into the dough without the need for kneading. It will also give your sourdough loaf a lofty high rise and more open interior crumb.
If you peter out and don't knead your dough enough by hand, or if you don't allow it enough time in your mixer, the dough will lack strength. It is a tell-tale sign of not enough kneading if your bread dough cannot hold its shape or acts listless and fails to inflate. Instead of rising, the dough will spread out flat.
As with the experiment described above, one dough was autolysed and stretched and folded four times; the other was mixed all at once and left untouched until the end of the bulk fermentation. In this experiment, the No Knead loaf was by far the winner.
Stretching and folding is what replaces kneading in many sourdough recipes. Stretching and folding helps activate the gluten in wheat flour, making it easier to work with and shape. If you skip stretching and folding, chances are you will end up with soggy dough that doesn't hold its shape before or during baking.
In short, to “activate” each, you simply add flour and water, stir, and wait — that's all there is to feeding a sourdough starter.
INSTRUCTIONS FOR ACTIVATING A SOURDOUGH STARTER
Cover the jar with a coffee filter or breathable material secured with rubber band and culture the starter in a warm place (70-80°F) for 12-24 hours. After 12-24 hours, feed the starter with an additional 2 Tbsp. of flour and 2 tbsp water. Stir thoroughly.
Most sourdough bakers appear to prefer using 'stretch and fold' techniques to work their dough. But traditionally, many bakers knead.
FIRST TWO WEEKS - a paper towel or light cotton cloth (secured with an elastic band) when first establishing your sourdough starter. WHEN PUTTING IN THE FRIDGE - a tight fitting lid (as long as the jar is large enough) is perfect when storing your sourdough starter in the fridge.
Once the gluten network has formed, over handling the dough can cause this network to break down. You really only need to handle sourdough minimally. Each set of stretch and folds should consist of 4 stretches and folds. You should aim to do around 4 to 6 sets, but you may need less depending on the dough strength.
Knead dough by hand for 15-20 minutes: Knead 5-10 minutes at a time, taking breaks in between. Avoid using a mixer for the kneading process, which can heat up the dough too much and may not activate the gluten in the flour effectively. If using a mixer, always knead the last five minutes by hand.
Just know that the result will be a bit different than you expected. Bread Loaves made with over-kneaded dough commonly end up with a hard crust and dry interior. Often upon cutting, slices will crumble.
A starter stored in the fridge can be fed once a week. If you plan to use it often, you can store it for up to two months without feeding. When you want to use the starter again, remove it from the fridge for a few hours, then feed it every 12 hours for 36 hours before you make bread with it.
Things that WILL kill your sourdough starter
It's best to maintain your starter at comfortable room temperature (around 70°F), though a little higher or lower won't hurt anything. SEVERE NEGLECT: If you neglect your starter long enough, it will develop mold or signs of being overtaken by bad bacteria.
The longer you leave your dough in the refrigerator, the more sour and complex flavors it will develop. You can easily leave a loaf in the refrigerator for 3 days before baking. I've gone as long as 5 days, but you will see some deterioration of the loaf after Day 3.
Oxygen: Fermenting sourdough starters will produce carbon dioxide. The starter should be loosely covered in order to safely release the gas, but the culture does not require oxygen.
Things that Will Kill A Sourdough Starter
Starvation - if you don't feed your starter for a long period of time it will develop harmful bacteria and mold. This will smell terrible and look orange, pink or fuzzy and green.
If you see hooch on top of your starter, you can simply stir it straight into the starter, and feed your starter the way you normally would. There is no need to drain the hooch out. (This can complicate your hydration levels).
Kneading is all about getting energy into dough to enhance its elasticity. It doesn't matter that much how you do it. I agree with this sentence about half-way: if you are just getting started with bread making, don't let not knowing the “best” kneading technique become an obstacle that keeps you from baking.
The slap and fold technique is a method of building strength in high hydration doughs. Doughs with a very high percentage of water are notoriously sticky and difficult to work with, but the slap and fold technique uses that stickiness to its advantage to build gluten strength in the dough.
Overkneaded dough will be tough and make tough, chewy bread. If you've kneaded by hand, you don't need to be too worried about overworked dough—you'll start to notice it getting difficult to manage. It takes a lot of elbow grease to knead bread dough; you'll likely tire yourself out before you can over-knead.
The very short answer is, your sourdough starter generally will be at its peak anything between 4 and 12 hours after feeding.
Getting ready to bake
Let it rest at room temperature for about 8 to 12 hours, until bubbly. Repeat as necessary, every 12 hours, until you notice the starter doubling or tripling in volume in 6 to 8 hours. That means it's strong enough to leaven bread.