The most common reasons are:
Weak, not enough active leaven.
- If the sourdough not strong enough, it will not be able to ferment the dough properly, so it will not be airy enough and will flatten during baking. The mature sourdough should be bubbly and have a slightly sour smell, and should at least double in size in a few hours in a warm place (20-25 °C).
- The leaven needs to be fed and refreshed every day, twice a day in the summer when it is hot, because it works faster. It is important to feed with quality flour, I advise feeding with at least BL80 Bread Flour, but for me mixed with wholemeal flour or higher protein flour works best.
- In my experience, the best results are achieved if you feed your sourdough 4-6 hours before baking, depending on whether it is winter or summer. In winter you can allow 8 hours. In summer, I usually use 4-6 hours. I like to feed my sourdough harder like this: 50 g sourdough + 80 g lukewarm water + 100 g flour. (This is my basic recipe.)
Too long or too short access.
- If the dough over rises, the gluten structure weakens and the bread collapses.
- If it does not rise enough, it cannot rise properly during baking.
- Optimally risen dough is elastic and, if you press it gently, it slowly returns to its original shape.
Inappropriate flour.
- For good sourdough bread, a high protein (12-16%) flour is best, and I mix this with BL80 bread flour or other wholemeal flours.
Too high hydration.
- That is, when the proportion of water in the dough is too high compared to the flour. In this case, the dough is very soft, difficult to shape and cannot hold its shape, so it spreads out and flattens during baking.
- For beginners, it is recommended to work with a hydration of around 65-70%, i.e. 65-70 g of water per 100 g of flour.
- Higher (above 75%) hydration can only be achieved with strong, high-protein flour and appropriate technique (longer kneading, Folding service, firm shaping) is worth using, otherwise the dough will not hold together.
- If the dough is too moist, it will easily run out in the oven, stay flat and make it harder to form an airy structure.
Formatting error.
- If you don't shape the dough tightly enough, it won't hold its shape and will spread and flatten during baking. I usually pre-shape first, let it rest for 15 minutes and then do the final shaping.
Improper baking technique.
- If the oven is not hot enough at the beginning or there is not enough steam, the bread will not rise suddenly but will remain flat. Steam is needed in the first stage of baking to prevent a hard crust from rising immediately, which would prevent the dough from expanding.
- For beginners I recommend baking bread in a cast iron pan, it was the easiest for me when I started baking bread, later I switched to baking on a pizza stone. Both baking techniques give very nice results, but it's important to make sure you have the right steam in both cases.
Kept on the counter sourdough is ideal if you bake with it regularly, as it keeps your sourdough active.
The advantage is that it is always easy to use and powerful, so it produces consistently good quality breads.
The disadvantage is that it requires daily feeding (up to twice or three times a day in summer), especially in hot weather. This can be more time consuming, and if feeding is not sourdough can quickly weaken or over-age.
It can be kept in small quantities, so less surplus is produced.
I prefer it this way, I only put my sourdough in the fridge if we are going on holiday or I know I won't be able to feed it for days.
Keeping sourdough in the fridge is recommended especially if you bake less frequently (once a week or less).
The advantage is that activity slows down, feeding once or twice a week is sufficient. This means little time is needed to care for them and no need to worry about over-ripening sourdough because of.
The disadvantage is that the leaven needs to be "strengthened" again before use - this means more feeding and a few days at room temperature to regain its original strength.
The refrigerator should not be colder than 5-6°C, as this can damage the leaven.
