Sourdough typically undergoes two main proofing stages: the first, long bulk fermentation (with folds), and the second, shorter final proof after shaping, often done cold in the fridge overnight for flavor and rise. While the exact timing varies with temperature and starter, you're looking for the dough to nearly double in bulk fermentation and then become puffy and spring back slowly (the poke test) for the final proof before baking.
To proof them, let them sit, covered, at room temperature for up to 3–4 hours, or let them proof for a little while at room temperature and then place in the refrigerator for 12–15 hours. Or you can speed the process by using a proof box, warm cooler, or slightly warm oven to speed things up.
The dough is ready when it looks slightly puffy and passes the poke test--press a finger in gently, and it should spring back slowly. If it stays deep, it's overproofed. If it bounces back too fast, it needs more time.
The biggest mistake beginners make with sourdough is impatience, specifically baking with a starter that isn't strong enough or rushing fermentation, leading to flat, dense bread; they often try to bake too soon, don't let dough proof long enough, and fail to develop dough strength or learn to "read the dough" (look/feel) rather than just the clock, plus starting with overly high hydration is a common pitfall.
The dough should be left to expand enough to give us a nicely textured crumb and a loaf that “springs” in the oven. Leave it too long and you run the risk of over proofing resulting in the dough deflating.
This is the second proofing stage which can take anywhere between 12-48 hours. The longer you proof the dough, the more acidic it will become, and the more the gluten will be broken down.
High starter quantities speed up fermentation and lower quantities slow down fermentation. For example, a recipe with 20% starter may finish bulk fermentation in 5 hours and at 10% starter, it may take 8 hours.
While your sourdough is proofing during bulk fermentation the acidity level slowly rises. While this imparts your bread with its typical sourdough flavor, it also has a strengthening effect on your sourdough. So if you're doing too many sets of stretch and folds that acidity will over-strengthen your dough!
The 1:1:1 method for sourdough starter is a feeding ratio using equal weights of starter, flour, and water, such as 50g starter, 50g flour, and 50g water, measured by a kitchen scale. This ratio is common for maintenance, keeps acidity low by providing abundant food, and helps maintain a balanced, active starter ready for baking, often doubling in 4-12 hours at room temperature, depending on warmth.
An overfed starter can be too diluted and it will be very watery. Your workers are there, they are just overwhelmed with too much food and water.
There are many indicators but the most reliable is to accurately measure the percentage rise in the dough. However, in my experience, the percent rise is temperature dependent. When bulk fermenting at a dough temperature of 80F/28C, I look for a 30-35% rise in the dough.
Proofing (aka final fermentation, final rise, second rise, or blooming) is the dough's final rise that happens after shaping and just before baking. The entire dough fermentation process is sometimes referred to as the proofing process.
In order to get the best texture and flavor that is typical of leavened bread, dough should be given a second proof before baking. ... The second rise helps develop a lighter, chewier texture, and a more complex flavor.
If your kitchen is warm enough, leave it on the counter overnight. If you have a colder kitchen consider placing it in the TURNED OFF oven with the light on (this provides a steady ambient temperature, so long as it's not too hot). Or, if you have another warm area you prefer, use that instead.
Method
The biggest mistake with a sourdough starter is impatience, primarily by using it before it's strong enough (weak starter) or discarding too much/feeding inefficiently, which weakens it further, leading to flat bread; you must give a new starter weeks to mature and consistently feed it at its peak for proper leavening power. Other common errors include using chlorinated water, incorrect water temperature, or ignoring temperature for sluggish activity.
Your sourdough starter should be bubbling and rising up the sides of its container within 4 hours of feeding (always keep your starter in a container that has plenty of room for expansion!).
Dense sourdough almost always points to under fermentation or starter issues. When the yeast cannot produce enough gas, or the gluten network is not strong enough to hold that gas, the loaf bakes tight and heavy. Signs of dense or under fermented sourdough: Tight crumb with gumminess.
The first way to check is to simply poke the dough with your finger. If the dough bounces back without sticking to your finger, it's been kneaded enough. If it doesn't, you need to keep kneading.
Here are some signs that bulk fermentation is complete: Volume: your dough should increase by about 50% in size. Shape: the dough should have a dome shaped surface. Bubbles: you should see visible bubbles on the top and the sides of the dough.
Ideal temperature for sourdough
While your starter can handle some warmth, I don't recommend letting it go over 85°F—and definitely not above 90°F. The hotter it gets, the more acidic it becomes, which can weaken the gluten structure and cause your dough to overproof too quickly.
Sure! Either a cold location or use less starter; both methods will work. Instead of 100g of starter try a test-bake using 25g and see how long it takes. The flavor is usually enhanced with a long fermentation.