The good news is - it's easy to fix! Five ways to know your sourdough is under fermented are: Cracked scoring and large, over pronounced ears. Uneven crumb - tight crumb surrounding random larger holes.
The crumb structure of an under proofed loaf will be tight and gummy. Because it was not given enough time to develop and trap CO2 gasses, the crumb structure will be very dense, with uneven air bubbles.
Pinch off a piece of dough from your sourdough before you place it into it's fermentation container. Place the small piece of dough into a small shot glass. It will be easy to see when the dough in the glass has doubled. When this happens, the dough in your container should have also finished its fermentation.
An overproofed dough won't expand much during baking, and neither will an underproofed one. Overproofed doughs collapse due to a weakened gluten structure and excessive gas production, while underproofed doughs do not yet have quite enough carbon dioxide production to expand the dough significantly.
Dough made with a young sourdough starter just won't develop. It will stay very wet and sticky, rather than strengthen with each stretch and fold. No matter how long you leave it to ferment, the yeast and bacteria won't actually grow or change.
When the bulk fermentation goes too long — often when the dough more than doubles or triples in volume — the dough can over ferment. You know the dough has over fermented if, when you turn it out to shape it, it is very slack — if it's like a wet puddle — and very sticky and lacking any strength and elasticity.
CAUSE - gummy sourdough can be caused by a starter that's too young or inactive and or under fermentation. More often than not, gumminess is a result of under fermentation (cutting the bulk fermentation time too short).
If your sourdough crust won't brown up in the oven, chances are it is under fermented. Under fermented sourdough will also struggle to brown up in the toaster because of the high moisture content still in the bread.
Over proofed dough has had it's gluten “eaten” or broken down to the point that the strength is gone. The sugars are used up so the crust won't brown properly. The crust is brittle, hard and pale without a beautiful shine. It smells reminiscent of crackers or corn and has a slight flavor that resembles that too.
If: The dough pops back out quickly – This means its under-proofed. The dough stays where it is – This means its over-proofed. The dough pops back out slowly and leaves a slight indentation – Perfect, your dough is ready!
If you suspect your dough is under proofed and you've already pre-shaped it then just give it an extra-long bench rest before you final shape it.
If your sourdough is not rising during bulk fermentation at all, you might need to strengthen your sourdough starter. If you notice the dough is under proofed during preshaping or shaping, simply give it a longer bench rest.
The crumb should be light and fluffy - not wet and gummy. The holes inside the sourdough may seem shiny. This is a sign that the gluten is very well developed.
The gases generated by the yeast have not been enough to inflate the dough. More fermentation or proof time is needed. If baked now, the loaf will rise some as the yeast responds to warmer temperatures, but then they die from the heat. This will be a stunted, perhaps misshapen loaf.
Gently press your finger into the dough on the top. If the dough springs back quickly, it's underproofed. If it springs back very slowly, it's properly proofed and ready to bake. Finally, if it never springs back, the dough is overproofed.
Under- or over-proofed bread will change the "crumb" of the bread but has nothing to do with food safety. If it is baked fully it will be safe even if it's a little dense or too airy.
After kneading, shape your loaf, cover it, and let it proof for 4-24 hours, depending on your specific sourdough starter and ambient temperature. You can manipulate the sourness of the bread with a longer rise time. A 24-hour rise time will produce much more sour bread than a 4-hour rise time.
Dough appearance should no longer be rough after sourdough bulk fermentation. It should be smooth looking and even a bit shiny. If you lift up a section, it should move together. You should see the formation of lines of gluten strands and/or webs of gluten that have formed.
If you leave your bulk fermentation at room temperature overnight it will likely overproof. You can put your dough in the refrigerator to slow things down until morning.
Overproofed sourdough is preventable but also salvageable. Reshape the dough, bake it as a pizza or flatbread dough, or bake it and turn it into breadcrumbs for granola.
Bread too dense? It might be cold dough. One of the most common mistakes is having a dough temperature that's too low for the starter to feed on all the flour in the dough, resulting in a crumb that's dense, with fewer openings. "Starter is happiest and most active at around 75 degrees.
A gummy crumb is a common trait of under or over-proofed sourdough. Learning to tell when the dough is ready for the next stage is key to making perfect sourdough. It occurs where the gluten structure collapses (over-proofing) or remains compact (under-proofing), making it hard for moisture to escape.
The perfect piece of sourdough is chewy and distinctively tangy, more complex in flavor than white bread, and healthier, too. Raw sourdough is home to the same bacteria that are in yogurt, Lactobacilli, which consumes the flour in the same way as yeast, breaking down some of the gluten proteins while the bread rises.