Capturing Microbes from the Air? The Magic of Sourdough Fermentation

Have you ever tried sourdough?

Commercial sourdough often uses isolated, high-purity yeast, which speeds up production and ensures more consistent quality. However, these advantages come at the cost of the more distinctive flavours, textures, and mouthfeel provided by traditional mixed microbial cultures.

In reality, yeast is omnipresent in our environment. By simply creating the right conditions for them to thrive, we can “capture” the microorganisms needed to ferment and bake sourdough bread.

In this episode of *The Alchemy of Food*, we have invited Yi Jian, the founder of Jane & Lucy, to demonstrate how to make a sourdough starter and the bread itself. To begin, we will need 50g each of wholemeal flour and water.

Mix equal parts water and wholemeal flour (1:1) until well combined, then cover and place in a cool, well-ventilated area.

Every day, discard half of the mixture and replenish it with another 50g of wholemeal flour and 50g of water. After about 3 to 5 days, you should start to see bubbles forming in the jar.

Next, you can continue cultivating the starter with ordinary flour, adjusting the water-to-flour ratio to 1.25:1. After another 3 days or so, once the jar is full of bubbles, the starter is active enough to be used for baking.

It is best to feed your starter daily to keep it active. A higher feeding ratio reduces the acidity of the environment, giving the yeast a competitive advantage.

Specifically, leave a small amount of the old starter in the jar, add water and flour at a 1.25:1 ratio, stir well, cover, and let it ferment in a cool, ventilated spot overnight (12 hours) before storing it in the fridge.

If you don’t plan to use it for a while, you can freeze or dry a portion of the starter to use as a seed for next time, so you don’t have to start from scratch.

Natural starter is a complex culture containing yeast, lactic acid bacteria, and acetic acid bacteria. Both the acetic and lactic acid bacteria produce acidic substances, resulting in bread with a characteristic tang and complex layers of flavour—hence the name “sourdough”.

To bake sourdough using your homemade starter, you will need: