Now that we have learned how to make Sourdough at home, let’s take another step ahead, and we will learn how to feed sourdough starter.

Feeding the Sourdough Starter means providing yeasts and bacteria with water and the “food” necessary to survive. Refreshment is an easy operation that involves kneading the sourdough starter, flour, and water.

When it comes to feeding Sourdough, we can distinguish 2 different goals:

• Daily Refreshments to maintain and preserve the sourdough day by day. This type of refreshment is intended to keep our starter alive.
• The 3 Refreshments to Prepare the Sourdough for the recipe: The primary purpose is to strengthen the yeast and stabilize its acidities (lactic and acetic).

This distinction is crucial because, as we will see, the two types of refreshments have different proportions of ingredients and procedures.

HOW TO FEED SOURDOUGH DAILY or WEEKLY to maintain it

Daily (or Weekly) refreshments are essential for keeping the Sourdough alive. It will be necessary to refresh it regularly, depending on how you store it. If you own the Sourdough at room temperature (18°C (64°F) to 22°C (71°F)), you will need to refresh it every day, whereas if you store it in the fridge (+4°C, 39°F), you can extend its storage up to 7 days.

A second factor to consider is the storage method: It may be soaked in water or tied up; this is very important because it will impact the Sourdough characteristics and require specific flour and sourdough proportions.

HOW TO REFRESH SOURDOUGH STARTER STORED IN WATER 

The Sourdough is characterized by a lower acidity (absorbed by water and higher humidity when soaked in water.

The first step in refreshing the Sourdough stored this way is to soak it in warm water at 38°C (100°F) and add 2gr/liter of sugar or fructose for 15 – 20 minutes. The water will absorb the exceeding acidity the Sourdough releases during the bath.

Once this time has elapsed, squeeze the Sourdough and knead it with these proportions:

• 1kg of Sourdough Starter
• 1kg of Bread Flour W360 (protein around 14% – 15%)
• 300g of water 30°C (86°F)

The dough should be well-formed, but it will not need to be over-kneaded. Once ready, roll out the Sourdough to about 1cm thick. Roll it tightly and place it in a bowl with cold tap water (19°C or 66°F).

The ideal proportion would be to soak the Sourdough at 3 times its water weight. Now you can keep your Sourdough at room temperature (between 18°C (64°F) and 22°C (71°F)) for 24 hours.

HOW TO FEED TIED-UP SOURDOUGH STARTER

This method is highly used in many bakeries in Italy. It refers to a sourdough stored in a heavy cloth and tied up with a rope.

Following this method, you will have a more acidic Sourdough starter (in particular, richer in lactic acidity and with less acetic acidity). 

In this case, the refreshment begins by soaking the Sourdough in lukewarm water 20°C (68°F) – 22°C (71°F) for 15 – 20 minutes, adding 2gr/liter of sugar or fructose.

I suggest weighing the starter before and after the bath to control better the amount of water used for refreshment. Hence, you know how much water has been absorbed during the bath and adjust the refreshment quantity.

Once squeezed and weighed, you can knead the Sourdough with this proportion:

• 1kg of Sourdough Starter
• 2kg of Bread Flour W360 (protein around 14% – 15%)
• 920 g Water (46% of flour weight) – the water absorbed during the soaking process.

As above, roll out the dough and form a loaf. Then, wrap it in plastic food wrap, roll it up inside a heavy cloth, and tie it up with string or rope.

I recommend leaving the cord slightly loose and allowing the Sourdough starter to “push” during the fermentation. Once ready, you can leave the Sourdough at room temperature (between 18°C (64°F) and 22°C (71°F)) for 16 hours.

THE 3 REFRESHMENTS TO REINFORCE THE SOURDOUGH STARTER BEFORE USING IT

Before using the sourdough starter in the recipes, it must be fed 2 or 3 times to strengthen it (producing more yeasts and lactic acid bacteria) and balance its acidity. Moreover, it promotes substances capable of preserving the product over time (if well packaged).

Big (and fat) leavened products (such as Panettone and Pandoro) need 2 or 3 refreshments, whereas 2 refreshments will be enough for simpler doughs such as croissants, bread, or pizza.

I will say that even for big leavened products, we can stop at the second refreshment in case of time needs, knowing that we may slightly lose a bit in their shelf life.

When starting a recipe with a sourdough starter, the first thing to consider is the amount of Sourdough we need to begin with to have the correct quantity for the recipe AND a reasonable amount to store.

That’s why I’ve developed a simple app that will help you know the exact amount of starter you need to refresh to make your recipe and not run out of Sourdough!

Click here to access the BiancoLievito application.

An essential aspect of refreshing Sourdough is obtaining a dough at a temperature of 24°C (75°F)—28°C (82°F), ideally 26°C (78°F).

For this, we can act on the water temperature and use this empirical formula:

Water Temp = 3 x final temp – room temp – flour temp – heat transmitted by the mixer (for a stand mixer, we can use 14°C).

!! Please note that this formula only works with Celsius degrees. Do the calculation in °C and then convert the result to °F !!

To obtain a dough at 26°C (78°F), imagining to have:

• Room Temp: 20°C (68°F)
• Flour Temp: 18°C (64°F)

The water temperature will be 3×26 – 20 -18 – 14 = 26°C (78°F)

THE 3 REFRESHMENTS FOR THE SOURDOUGH STORED IN WATER – UPDATED VERSION

After several years of feeding Sourdough (with good results) using a ration of Sourdough to flour of 1:0.9 (1kg of Sourdough and 900gr of flour), I experimented with different refreshment techniques. I’ve been inspired (and documented) by reading some texts that sparked my curiosity to put everything I had learned over the years back into play.

This new method of working starts with these primary considerations:

• Sourdough stored in the water has lower lactic acidity precisely because of its storage environment. For this reason, during the 2 or 3 preparatory refreshments, we should try to rebalance this acidity.
• The ratio between Sourdough and flour determines whether or not bacteria can reproduce. Using too much Sourdough and too little flour will result in a limited proliferation of bacteria and an unbalanced Sourdough. In the book “Omnia Fermenta” by G.Battista Montanari, you can read that the best biological conditions (scientifically proved) are obtained when the quantity of Sourdough is between 10%-30% of the total amount of fed dough. Let’s take an example with a 1:2 ratio. If I refresh 100gr of Sourdough + 200gr of flour +80gr of water, I get a total mass of 380gr, of which the Sourdough represents 26% of the total (100gr/380gr)

Here’s what I modified in this new method:

1. I let the Sourdough ferment out of the water between one refreshment and the next one, 
2. I use a sourdough-to-flour ratio of 1:1.5 (instead of 1:0.9)
3. I let the sourdough ferment until it reaches 2 ½ times its initial volume, i.e., initial volume +1.5 times.

Let’s see how to do it.

As a first step, soak the Sourdough in warm water at 38°C (100°F) for 15-20 minutes, adding 2g/l of sugar or fructose. After this time, squeeze the starter and refresh as follows:

FIRST REFRESHMENT

• 1kg of starter
• 1.5kg of Bread Flour (W380 – 14-16% protein)
• 690g of lukewarm water at the correct temperature (see above).

Knead until you have a firm and compact dough, roll out to 1cm thickness, and give 3 folds before forming a ball. Roll the dough tightly, score the surface to facilitate its development, and place it in a large bowl. Cover with a cloth and ferment for 3½ hours at 30°C (86°F) until it has increased 2½ times its volume (initial volume + 1.5). I suggest you place a portion of the dough into a glass, mark the initial level, and use it as an indicator for following the fermentation.

The fermentation time will be long enough for the Sourdough to multiply its microbial flora. The second refreshment is essential when the Sourdough starter is at the peak of its development. Usually, it happens after 3½ hours, at 30°C (86°F).

SECOND REFRESHMENT

• 1kg of Sourdough starter
• 1.5kg of Bread Flour (W380 – 14-16% protein)
• 690g of lukewarm water at the correct temperature (see above).

Once again, knead the ingredients, roll out the dough form a ball, and proceed as above, letting the sourdough ferment for 3½ hours at 30°C (86°F)

THIRD REFRESHMENT

• 1kg of Sourdough starter
• 1.5kg of Bread Flour (W380 – 14-16% protein)
• 690g of lukewarm water at the correct temperature (see above).

Knead the ingredients until they form the dough. Take the portion of Sourdough that you will store and weigh the amount needed for the recipe.

For the part that you will use in the recipe: Roll out the dough from a ball and proceed as above, letting the sourdough ferment for 3½ hours at 30°C (86°F)

For the part that you will be storing: Soak it in cold water (19°C (66°F)) and leave it 24 hours at room temperature (19°C – 20°C or 66°F to 68°F) until refreshed the next day.

After 3½ hours at 30°C, the Sourdough starter will be ready to be used!

THE 3 REFRESHMENTS FOR THE TIED-UP SOURDOUGH STARTER – UPDATED VERSION

In this case, soak the Sourdough in fresh water at 20°C – 22°C (68°F – 71°F) with 2gr/liter of sugar or fructose for 15-20minutes. As mentioned above, weigh the Sourdough before and after to see how much water is absorbed during the bath.

Once ready, do the 3 refreshments using this proportion:

FIRST REFRESHMENT

• 1kg of Sourdough Starter
• 2kg of Bread Flour (W380 – 14-16% protein)
• 920g of lukewarm water at the correct temperature (see above) – the water absorbed during the soaking process

Knead the dough and roll it out to 1cm thick. Form a tight ball, incise a cross-cut on the surface, place the dough in a bowl, and ferment for 3 and a half hours at 30°C (86°F) until it has increased 2½ times its volume (initial volume + 1.5).

SECOND REFRESHMENT

Perform the same procedure as described above, but mix the Sourdough in these proportions:

• 1kg of Sourdough Starter
• 1.5kg of Bread Flour (W380 – 14-16% protein)
• 690g lukewarm water at the correct temperature (see above)

THIRD REFRESHMENT

Follow the same steps as the second refreshment, but use the ingredient in these proportions:

• 1kg Sourdough Starter
• 1kg of Bread Flour (W380 – 14-16% protein)
• 460g of warm water at the correct temperature (see above).

Knead all the ingredients, weigh out the part of Sourdough needed for the recipe, and let it rise again for 3½ hours at 30°C (86°F). Wrap the remaining part in a plastic sheet and then in a heavy cloth, tie it with a string, and store it at room temperature (19°C – 20°C or 66°F to 68°F) for 16 hours.