Everything you need to know about Sourdough Starters
13 August 2021

What is a Sourdough Starter

What are sourdough starters? Well sourdough differs from a more conventional bread in that it is not leavened by manufactured yeast. Instead it relies on a natural yeast introduced to the bread dough via what we call a starter.

When we talk about a starter what we mean is a fermented mixture of flour and water. This contains the natural yeast and bacteria that causes the bread to rise. 

The process of fermenting the starter makes use of the natural microbes within the flour and the air. These microbes are key to the production of the leavening agent within a sourdough starter. Below we will look at how this process actually works.

The Science

Sourdough relies on the existence of two types of microbes in the flour and air. In this case it is yeast and lactic acid bacteria.

The relationship between these two is symbiotic. The yeast cannot digest the maltose sugar that is formed by enzymes breaking down the starch in the flour. Whereas the lactic acid bacteria can break this maltose down into a simpler glucose that the yeast is then able to digest.

This process of yeast digesting the glucose in the mixture is the fermentation that produces the carbon dioxide and ethanol. These give the bread its rise.

Sourdough starter does take longer to produce a desirable rise than a baker’s yeast. Under some circumstances though, sourdough can produce a significant amount more carbon dioxide, which is the key component in producing the finished rise.

This is the reason why you often see large open air bubbles inside sourdough loaves. I should also mention that sourdough starter has a more acidic pH level. This can slightly weaken the gluten strands in a loaf and can end up producing a denser bread. 

Sourdough starter differs from using a refined yeast, as the sourdough starter is much more delicate than the baker’s yeasts.

A baker’s yeast can be very simply added directly into a dough. A sourdough starter needs a lot more care and attention. This is mainly because a sourdough starter is a living system, so needs to be fed and maintained. Baker’s yeast is normally dried or treated so it is more stable and easier to use. 

Making Your Starter

Making a sourdough starter is a very simple thing, and relies on very little in the way of ingredients. You can amend any recipes for sourdough starter to produce the amount of yield you need depending on how much you can store and what level of baking you will be doing.

For me, when it comes to home baking I usually use a standard 250g of strong white bread flour to produce my starter. Below I will put the specific recipe that I use whenever I make a sourdough starter for myself at home:

Firstly, I take 50g of the flour and mix it with 50g of tepid water in a plastic container or jar. Make sure to mix in all of the flour and leave it partially covered at room temperature for 24 hours.

Repeat the same process of mixing 50g of flour with tepid water. Then combine this with the original flour mixture over the following few days until all of the flour has been incorporated into the initial mix. After 4 days you should begin to see some activity. After the fifth day the activity level should be significant. You should notice a yoghurt-like smell when the starter is ready to use.

Once the sourdough starter is ready, you can store it ready for use in whatever way makes the most sense according to your usage.

We will look into the best way of storing and maintaining your new sourdough starter below.

Maintaining the Starter

The ongoing maintenance of your sourdough starter is arguably as important as the initial production of the starter. A sourdough starter differs from lots of other products used in a bakery as it is a living entity. It is a lot more fickle and delicate than almost any other bakery ingredient.

When it comes to looking after our own sourdoughs at home, there are several key things to remember. Perhaps the most known is the need to feed your starter.

As I said above a sourdough starter is a living thing, and therefore it is important to feed it according to its specific needs. The feeding schedule needed depends on how you choose to store your starter.

For those less frequent bakers, it will be a lot easier to store the starter in the fridge, whereas if you are baking daily you may choose to store the starter at room temperature instead.

If you are storing your starter in the fridge then you will need to feed it around once per week, and if it is stored at room temperature you will want to be feeding the starter once per day.

When feeding the starter, consider the time in which you will want to use it. Under normal room temperature I usually find that the starter is ready for use about 5-6 hours after it has been fed, but it can depend on the room temperature and dough temperature. Once the starter has doubled in volume it is ready to use.

You can simply remove the amount needed for the baking you plan to do and then store the starter at room temperature for three to four hours before replacing it into the fridge for storage again. 

You can repeat this process over and over again as required, and continue to store the sourdough starter in the fridge.

Does the Starter make Sourdough more healthy?

There have been many questions about whether or not it presents a healthier option than a more conventional bread.

There are two main considerations to take into account when answering this question. The first of which is simply to do with the production of the breads you are comparing.

When compared to a mass produced loaf there are added components that reduce the nutritional benefits. It is fairer to compare a homemade loaf of sourdough to an equivalent made with a conventional bakers yeast.

The findings so far seem to confirm that sourdough bread does have a lower glycemic index, which means that sourdough has a lower increase on blood sugar levels. The sugars also enter the bloodstream slower than they do with a conventional bread. 

Sourdough is also easier to digest for many people, and this is because sourdough starter has both probiotic and prebiotic-like properties. This means that it contains non-digestible fibres that feed the good bacteria in your gut. Making it beneficial to those who normally suffer from digestive issues when eating bread. 

To watch the ultimate sourdough starter guide, see the video here: https://www.youtube.com/watch?v=sTAiDki7AQA

For more information and other recipes on breads check out The Online Pastry School courses and sign up for 30 days free: https://becomeapastrychef.co.uk/login-register/


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