Having a healthy and well-balanced Sourdough is essential for succeeding in your recipes.
However, it’s not always easy to check when the Sourdough is correctly acidic. We have to consider 2 acidities: Lactic and acetic, and both are essential for the correct balance of the starter.
Let’s see how to read the Sourdough’s primary signals and eventually try to fix them quickly.
Sourdough is a unique environment made of lactic bacteria and yeasts; both these organisms live in symbiosis and are needed by each other.
Sourdough’s acidity is determined by this balance.
Lactic bacteria are responsible for the production of Lactic Acid. In contrast, Yeasts produce Acetic Acid due to their metabolism, contributing to determine Acetic acidity.
The ratio between the number of lactic bacteria and yeasts must also be balanced.
It all seems very logical and immediate theoretically, but how can we handle this at home?
Although this may seem quite complicated, in reality, the best way to manage it is to:
- Check the status of your Sourdough acidity during every refreshment: is it too acidic or too weak?
- Distinguish the cause of the excessive acidity: Does it come from an excessive lactic or acetic acidity?
- Appropriately feed the Sourdough to restore a balanced acidity.
Let’s see how to do it!
HOW TO REBALANCE THE OVER ACIDITY IN SOURDOUGH
An over acidic Sourdough has specific characteristics:
- A Sticky or excessively stiff consistency
- Sour taste (you will feel it in the back of the tongue) or strongly metallic flavor
- During the bath at 38°C (100°F) in slightly sweetened water, the starter remains at the bottom of the bowl.
In case you recognize these characteristics, your Sourdough is definitely too acidic. Now, let’s see how to distinguish the nature of it.
EXCESSIVE LACTIC ACIDITY
The most visible symptom of excessive lactic acidity is:
- Sticky consistency: Excessive acidity deteriorates the gluten and tends to make the dough sticky
- Bitter taste (you will feel it in the back of the tongue)
Using Sourdough with an excess of lactic acidity will cause many problems during the kneading process, especially when you add fats. Therefore I suggest you pay particular attention to this aspect.
For fixing this problem, it will be necessary to promote the development of yeasts and at the same time to keep under control the proliferation of lactic acid bacteria.
To do this, first, soak the Sourdough in 38°C (100°F) water, added with 4gr/l of sugar or fructose, and leave it for 20 minutes.
Once ready, squeeze the starter and feed it with a starter-to-flour ratio of 1:1.2 (1kg yeast to 1.2kg flour), using fresh water at 22°C (71°F) to 24°C (75°F) in the following proportion:
- Hydrate at 30% the amount of flour that is equal to the yeast
- Hydrate at 50% the flour that exceeds the amount of yeast
Let’s take an example: If we have 1kg of Sourdough refreshed with a 1:1.2 ratio, I will use 1.2kg of flour.
To get the correct amount of water, I will need to:
Hydrate at 30% the quantity of flour that “covers” the weight of the starter (1kg x 30%): 300gr of water
Hydrate at 50% the amount of flour that exceeds the weight of the starter (1.2gr -1kg of yeast = 200gr x 50%): 100gr of water
The total quantity of water to use for the refreshment will be 300gr + 100gr = 400gr.
After weighing all the ingredients, knead the starter, the flour, and the water. It is essential at this stage not to over-knead the dough.
When the dough is ready, roll it out, form a loaf and finally soak it in cold tap water (about 19°C, 66°F) and leave it at room temperature (20°C, 68°F) for 24 hours.
Suppose the room temperature exceeds 20°C – 22°C (68°F – 71°F). In that case, I recommend waiting for the Sourdough to rise to the surface and then placing it in the fridge at +4°C (39°F) for the remaining time.
Essentially, the factors that allow the starter to develop yeasts better than lactic bacteria are:
- The lower temperature of the water (21-24°C, 69°F -75°F)
- The lower hydration of the dough (30% of water)
- A direct mix of the ingredients (we knead all the ingredients at the same time)
- A Shorter kneading process
EXCESSIVE ACETIC ACIDITY
In contrast to lactic acidity, a starter that has developed too many yeasts will have the following features:
- A quite stiff consistency
- Few gas bubbles (alveoli)
- Spicy taste at the tip of the tongue
- Emphasize sour scent to the nose, close to the vinegar
Very often, when a starter has these characteristics, it’s called (in Italy) “too strong.” However, even in this case, we need to rebalance the two acidities and allow the Sourdough to develop a higher concentration of lactic bacteria.
For this, soak the starter in the water at 38°C (100°F) with 2 grams/liter of sugar or fructose. Leave it up to 15 minutes. After this time, squeeze out the starter and feed it using 35% of water over the yeast’s weight (350g of water for 1kg of starter). Contrary to the previous case, it will be essential to use the correct water temperature to obtain a dough at 28°C (82°F).
For this, you can use this “empirical” formula that I learned from the chef Giambattista Montanari:
Water Temp = 4 x final Temp – Flour Temp – Room Temp – Kneading heating (for a stand mixer use 14°C, 8°C for a twin arm mixer, and 18°C for a spiral mixer) – Yeast Temp
!!! This formula only works with °C. You can apply the formula with °C and covert the result to °F !!!
In the realistic case with a room temperature of 20°C (68°F), a flour temperature of 19°C (66°F), the starter at 18°C (64°F) and using a stand mixer, I can get the final dough at 28°C (82°F), using the water at this temperature:
Temp Water = (4×28) -20 -19 -14-18 = 41°C (105°F)
Contrary to the previous case, after the bath, dissolve the starter into the water using a stand mixer. Then add the flour, keeping the starter to flour ratio of 1:1.2.
Knead the dough a bit longer until it is homogenous and smooth.
Once again, the main factors that promote the development of lactic bacteria are:
- A Higher water temperature to obtain a dough at 28°C (82°F)
- Higher hydration of the dough (35% of water over the starter’s weight)
- Dissolve the starter into the lukewarm water
- A longer kneading process
STRENGTHEN A WEAK SOURDOUGH
The opposite case of acidic Sourdough is when the starter is weak, i.e., with a low proliferation of yeast and bacteria flora.
You can recognize when the starter is too weak by these factors:
- During the bath, it will come to the surface immediately (within 7 – 8 minutes)
- The scent of flour, without any sour note
- Few gas bubbles (alveoli) in the dough
To reinforce the starter do a cycle of 3 refreshments, each one of them with 3 hours of fermentation, and use a starter to flour ratio as explained below:
- Refreshment 1: Mix 1kg of starter with 800gr of flour and 240g of water at 30°C (86°F). Soak it in the water at 26°C (78°F) and ferment for 3 hours at 30°C (86°F)
- Refreshment 2: As above, but use a starter to flour ratio of 1:0.9 (1kg of starter, 900g of flour, and 270g of water at 30°C, 86°F).
- Refreshment 3: As above, but once the dough is ready, soak it in cold water at 19°C (66°F) and let it ferment for 24 hours at room temperature.
For succeeding in homemade bread or an excellent Panettone, it is crucial to have a Sourdough with balanced acidity and fix any excess of it before starting the recipe.
The best way to do this is to check the Sourdough’s status daily and feed it correctly until it is back to the correct acidity.