There are corners of Instagram where photos of beautifully scored loaves, crumb shots and the hashtag #sourdough abound. Where discussions revolve around hydration, refreshment schedules and proving times, and tips are swapped for getting the best oven spring. But this fascination with all things sourdough isn’t limited to the internet. While sourdough might once have been a minority interest, viewed by some as a specialist bread, now there is an artisan bakery in almost every town and a phenomenal increase in the number of sourdough starters being carefully nurtured up and down the country.

Sourdough bread has a long, long history. Its origins are uncertain, but the first leavened loaves to be baked would have involved naturally occurring yeasts which somehow found their way into the flour and water mix that was used to make flatbreads thousands of years ago. The process of using a small portion of naturally fermenting dough to produce richly flavoured breads continued until the introduction of commercially produced yeasts in the 19th century. These new yeasts were easier to store, faster acting and produced a more consistent product. They were soon adopted by bakers, and sourdough lost much of its attraction.

But now is sourdough’s time to shine again. Sales of naturally-leavened loaves are pushing the sliced white off the shelves, and home bakers are embracing the challenge of this most natural form of baking. Some people point to the newfound popularity of brunch, and in particular smashed avocado on toast, as the source of this sourdough renaissance. But most bakers are pretty sure that this is not a passing phase, rather a recognition of the nutritional value of sourdough… and the fact that it tastes really good. A good sourdough loaf is crusty and chewy, with a depth of flavour you’ll never get from a mass produced loaf. And all this great flavour comes from just three ingredients… flour, water and salt.

At the heart of every good sourdough loaf is the starter. A mixture of flour and water that, with time and a little care, becomes populated with an active community of wild yeasts and bacteria. The acids and other compounds produced by these microbes during fermentation are what gives sourdough its distinctive tangy flavour. The natural yeasts work more slowly than commercially produced baker’s yeast, so the sourdough fermentation process is slower. Typically it takes 24 hours or more from mixing the ingredients to pulling a freshly baked sourdough loaf from the oven – in contrast, a yeasted loaf can be mixed, baked, sliced and plastic wrapped in a little over three hours.

Even the supermarkets are seeing a sourdough effect, with some reporting demand increasing by almost 40% last year. This means there is now a wider range of sourdough products being offered to shoppers. But the Real Bread Campaign warns bread lovers that not all loaves labelled as sourdough are the genuine article. There’s no legal definition of sourdough, so it’s always good to talk to the baker and ask about the ingredients they use (there should be no yeast, dough improvers or preservatives), and how long the dough is proved for.

Flavour aside, there is a growing body of research suggesting that slow fermented sourdough may be easier to digest and have higher nutritional value. What started out as anecdotal evidence is now being supported through clinical trials. Many people who had excluded bread from their diet due to gluten intolerance have found that they are able to eat sourdough without any of the discomfort associated with industrially produced, yeasted bread. This is thought to be due to the long, slow fermentation, which breaks down the carbohydrates to a form that can be more easily digested. The sourdough fermentation process also helps increase the bioavailability of vitamins and minerals, making them easier to absorb during digestion.

If you’d like to find out more about this amazing, slow bread, there will be workshops and promotions across the country next month for Sourdough September. Organised by the Real Bread Campaign, this now annual event aims to encourage everyone to eat and learn more about sourdough.

Sarah Smith @theworddeli

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