What Causes Sourdough Bread to be Raw and Undercooked?

There are 4 reasons why your sourdough is undercooked and raw in the middle

1. Insufficient baking time when baking a heavier loaf

Sourdough bread is fully baked when its internal temperature reaches 88 Celcius, which applies to any loaf size. However, it takes a longer time for a larger and heavier loaf to reach this internal temperature of 88 Celcius as there is more mass that needs to be heated up.

Most home bakers do not bake with a digital thermometer, and we often rely on the color of the crust and baking time to help us determine when the loaf is fully baked.

When baking heavier loaves of bread, we should increase the baking time to ensure that the internal temperature of the bread has reached 88 Celcius when we remove it from the oven, otherwise we will get bread that is undercooked and raw in the middle.

The table below shows the appropriate baking time in relation to the weight of the loaf.

Weight of Loaf (grams)Baking Time (minutes)Baking Temperature (Celcius)

2. Excessively high oven temperature

We typically rely on the coloration of the crust as an indicator of when the loaf has finished baking; when the crust has taken on a sufficiently dark coloration, we say that the loaf has finished baking and that works most of the time. However, this method does not work if we are baking at a higher temperature.

The high temperature causes the crust to brown and darken very rapidly, however too little time has passed for the centre of the loaf to be fully cooked.

Hence, lower the oven temperature if you find that your crust is browning or darkening too quickly, to allow the loaf to achieve a full bake (reaching an internal temperature of 88 Celcius) without burning the crust.

3. Not preheating the oven

We should always preheat our oven to the desired temperature before loading the dough. As it takes 10-15 minutes for the oven to rise in temperature, loading the loaf into a cold oven can easily cause it to be undercooked as the internal temperature in the loaf rises much more slowly and does not reach the required 88 Celcius at the end of the bake.

If you have loaded a loaf into an oven that is not preheated, you can ensure the loaf is fully cooked by adding an additional 10-15 minutes to the baking time.

4. Insufficient cooling

Insufficient cooling causes sourdough bread to be rock hard on the outside, but feels raw in the middle.

During baking, starch molecules are swollen with water through a process known as starch gelatinization. Cooling allows the moisture in the starch molecules to dissipate and be absorbed by the dry crumb. The movement of moisture out of the starch molecules (starch retrogradation) and into the crust prevents the crumb from becoming gummy and allows the dry crust to moisten and soften.

If we slice open a hot sourdough bread immediately after it leaves the oven, moisture in the starch molecules does not have time to dissipate, the starch molecules exists in a gelatinized state, which causes the crumb to be gummy and gooey in texture. No moisture is absorbed by the crust, and it remains dry and hard.

We typically allow sourdough bread to cool for at least 4 hours before slicing open to ensure that all the moisture in the starch has been allowed to dissipate, leaving us with a moist but not gummy crumb.

How to know when my sourdough bread has finished baking?

1. Measure the internal temperature

The most consistent and accurate method for determining if your sourdough bread has finished baking is through the use of a cooking digital thermometer. Your sourdough has finished baking when the centre of the loaf registers 88 Celcius on the thermometer.

There are two kinds of cooking thermometer used in baking.

  • Instant read thermometer – temperature probe is inserted into the centre of the dough and removed once temperature is taken; it gives you a temperature reading at one instance of time, it does not track changes in temperature over a length of time.
  • Digital thermometer – temperature probe is left in the centre of the dough throughout the bake to give you a live temperature reading which tracks the changes of temperature over a length of time.
Instant Read Thermometer
Digital Thermometer

A digital thermometer is the recommended choice as it allows you to leave the oven door shut throughout the baking process, but you are still able to get a temperature reading throughout the baking process.

With an instant thermometer, you have to open the oven door, causing the oven temperature to fall every time you want to take a reading. It is more hassle, and can unnecessarily prolong the baking time, resulting in a drier loaf.

2. Knock test

If you do not own a thermometer, another common method to determine when your sourdough bread has finished baking is to lightly tap the bottom of the loaf. When it sounds hollow, it has finished baking.

Can you save an undercooked bread?

You can load the undercooked bread back into the oven and continue baking, this will finish cooking the parts of the bread that is still raw. If you have not sliced open the loaf, the effects of reloading the undercooked loaf into the oven will be minimal.

However, if you have sliced open the loaf, reloading the undercooked loaf into the oven will cause your loaf to be significantly dried out, as the porous crumb structure of the loaf allows moisture to easily dissipate out of the loaf and into the environment. It is still better to eat dry bread than to throw away bread that is undercooked.

Can you get sick from eating undercooked sourdough bread?

My recommendation is to not do it. It taste awful, and undercooked sourdough bread contains a ton of microbial organisms which can be detrimental to your health if eaten. It is better to reload the undercooked loaf into the oven and be satisfied with a drier loaf.


Hey there! I'm Sam, your go-to pal for all things sourdough. I've been baking and kneading for 10 fun-filled years, and I can't wait to share the joy of turning simple ingredients into heavenly sourdough bread with you. Grab your apron and let's dive into this amazing world of sourdough bread together on this blog.

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