From the depths of the oceans to the tops of the highest mountains, our planet is thought to be inhabited by as many as 10 million species of bacteria. We are part of this microbial world. Microbes live in us, on us and around us.

Recently there have been reports of a shortage of commercially manufactured yeast in the shops. Sourdough bakers leaven their bread using a culture of a small number of wild yeast and lactic acid bacteria species. These wild yeasts and lactic acid bacteria occur naturally all around us; we simply need to capture them.

My life in sourdough

When I was in my early twenties, my microbial system was massively disrupted by antibiotics. Within a few weeks, I was unable to digest wheat. The very bread that I loved to bake was making me ill. It was only when I returned to the bakery in France where I’d trained that I realised I could digest sourdough.

The balance of my gut microbiota had been so severely disrupted that I had gut dysbiosis. The antibiotics had reduced my levels of beneficial gut microbes to less than two per cent diversity and my digestive system was struggling. I could digest sourdough because the process of breakdown that should have been happening in my gut was actually happening in the dough during the fermentation process.

This process helps to break down the gluten in the dough, making sourdough easier to digest for many people who have non-coeliac gluten sensitivity. Also, because of the way the sugars are broken down, sourdough is often better tolerated than fast-fermented, commercially produced bread by people who have IBS – up to 20 per cent of the population.

The process also increases the bio-availability of nutrients, minerals, vitamins and antioxidants, as well as increasing levels of resistant starch, meaning a slow-fermented bread can help slow down our blood sugar response.

I’m now working towards a PhD focused on sourdough and the gut microbiome, and how this relates to mental health.

The most basic of ingredients

To make sourdough, you simply need flour, water and salt. Using organic ingredients is vital. Just think about our symbiotic relationship with microbes: if we work with ingredients that have been covered with insecticides, we’re hugely reducing the natural microbial load that we want to nurture in our starter.

Sourdough connects us to the planet: to the soil, to the water, and to the people we share it with. Baking sourdough will not just produce a beautiful loaf – it will help you to truly understand this magical, microbial world in which we live.

Vanessa Kimbell is a sourdough specialist, baker, and teacher at the renowned Sourdough School in Northamptonshire.