Why Does My Sourdough Burn on the Bottom?

Sourdough develops a deeply coloured crust during baking. The base may naturally be darker than the top because it touches a hot baking surface.

A well-baked bottom can be dark brown and firm without tasting bitter. It becomes a problem when the crust turns black, smells burnt, tastes unpleasantly bitter, or becomes so hard that it is difficult to cut.

Look at the entire loaf. If only the base burns while the sides and top have a good colour, the problem is almost certainly excessive heat from below. If the whole loaf becomes too dark, the overall temperature or baking time may be too high.

Home ovens do not always distribute heat evenly.

In many electric ovens, the lower heating element sends intense radiant heat directly toward the baking vessel. Gas ovens can also be much hotter near the bottom, especially when the burner cycles on repeatedly to maintain a high temperature.

The temperature shown on the control panel is only the average temperature inside the oven. The area near the lower element may be considerably hotter.

This is why two bakers can follow the same recipe and get completely different results. One oven produces a golden base, while another burns it at the same stated temperature and baking time.

An inexpensive oven thermometer can help reveal whether the oven is hotter than the setting suggests. However, even an accurate thermometer may not show how strongly the bottom element heats the base of the loaf.

A cast-iron Dutch oven is excellent for sourdough because it traps steam and supports strong oven spring. It also stores a great deal of heat.

During a long preheat, the thick base becomes extremely hot. When cold dough is placed inside, the bottom of the loaf immediately receives intense contact heat. The top remains protected by steam, while the base continues browning against the hot metal.

This does not mean you should stop preheating the Dutch oven. A properly heated vessel helps the loaf rise and prevents sticking. Instead, the heat reaching the bottom needs to be softened.

Parchment paper makes transferring the dough easier, but one thin sheet provides very little insulation. Adding several layers may help slightly, although it will not correct severe heat from below.

A reusable silicone bread sling offers a little more protection, but it is still not a complete solution when the Dutch oven sits close to a powerful lower element.

Rack position can make a surprisingly large difference.

If the Dutch oven is placed on the lowest rack, move it to the middle or slightly above the middle of the oven. Increasing the distance from the heating element reduces the direct radiant heat reaching the base.

Make sure there is still enough space above the pot for air to circulate. The lid should not sit very close to the upper element.

If moving the rack is not enough, place an empty heavy baking sheet on the rack below the Dutch oven. The sheet acts as a heat shield by blocking part of the direct radiation from the lower element.

The shield should normally remain on a separate rack rather than touching the Dutch oven. This allows it to protect the base without interfering too much with the heat surrounding the loaf.

A baking stone can also diffuse heat in some ovens, but placing a Dutch oven directly on a very hot stone may make burning worse. Baking steel transfers heat even more aggressively and is rarely the best surface beneath a cast-iron pot when the bottom already burns.

Sourdough needs strong heat at the beginning of baking, but it does not always need the same temperature until the end.

The initial heat creates steam, expands the gases in the dough, and produces oven spring. Once the loaf has expanded and the crust has begun setting, the temperature can often be reduced.

For example, an oven may be preheated to 240–250°C, but the temperature can be lowered after the loaf is loaded. Depending on the oven and recipe, the covered stage may continue at approximately 230°C, followed by an uncovered stage at 210–220°C.

These are starting points rather than fixed rules. An oven that runs hot from below may need a reduction of another 10–20 degrees.

Do not lower the temperature so much that the loaf dries slowly for a very long time. A moderate reduction combined with a heat shield usually works better than baking at a very low temperature from the beginning.

Another option is to remove the loaf from the Dutch oven during the final 10–15 minutes and finish it directly on the oven rack. Once the bread is removed from the hot cast-iron base, the bottom stops receiving such intense contact heat.

A lean sourdough made from flour, water, salt, and starter tolerates high temperatures well. Dough containing sugar, honey, malt, milk, butter, or other fats browns much faster.

Even a small quantity of active malt can greatly increase crust colour. Seeds on the bottom of the loaf can also become bitter before the bread finishes baking.
If an enriched or malted sourdough burns underneath, it may need a lower temperature than a basic country loaf. The same baking schedule cannot always be used for both.

Check the flour as well. Some bread flours already contain malted barley flour or added enzymes. Adding more malt without considering what is already present can cause unusually rapid browning.

A thick layer of flour beneath the loaf may scorch and create a burnt smell even when the actual crust is not badly burned.

Before placing the dough into the Dutch oven, gently brush away heavy accumulations of flour from the base. Rice flour is useful in proofing baskets because it prevents sticking, but a thick loose layer can still darken and taste unpleasant after a long bake.

The same applies to bran, seeds, and coarse grains. Use enough to prevent sticking or add flavour, but avoid leaving a heavy pile directly beneath the loaf.

Trying to save the bottom by removing the bread too early can create a new problem: a gummy or damp crumb.

The loaf should feel light for its size, the crust should be well set, and the internal temperature of a lean wheat sourdough is often around 96–99°C when fully baked.

Internal temperature is helpful, but it should be considered together with the colour and firmness of the crust. A very wet loaf may need a little more time for moisture to escape even after the centre reaches a high temperature.
Once baking is finished, cool the bread on a rack. Leaving it on a hot tray or inside the Dutch oven allows the bottom to continue darkening and can trap moisture in the crust.

Allow the loaf to cool completely before deciding how badly it is burned.

A thin black layer can often be removed with a fine grater, bread knife, or serrated scraper. If the bitter flavour has not penetrated the crumb, the rest of the loaf will still be good.

For a severely burned base, cut away the darkest section and use the remaining bread for toast, croutons, or breadcrumbs.

The important part is to change the heat arrangement before the next bake. Simply shortening the baking time may hide the symptom while creating an underbaked centre.

A burned bottom usually does not mean the entire baking method is wrong. More often, the loaf is simply receiving too much concentrated heat from below.

Move the Dutch oven higher, place a baking sheet on the rack beneath it, reduce the temperature after the initial oven spring, or finish the loaf outside the pot. Also consider whether sugar, malt, seeds, or excess flour are making the crust darken faster.

The goal is not a pale base. A good sourdough should have a deeply baked, flavourful crust. It simply needs balanced heat so the bottom becomes crisp and brown without burning before the centre is ready.