It can take up to four days to make a traditional sourdough loaf, but supermarket versions often contain ingredients that aren't found in traditional sourdough, which speed up the process of making a loaf.
A closer look at the price per kg reveals that supermarket loaves aren't always much better value, either.
We explain what the difference is, and how to make the right choice for you.
Eat well, live better and stay healthy –What's the difference between sourdough and normal bread?
Traditional sourdough is a leavened bread. This means the dough rises naturally as a result of the gases released as the grain ferments. It contains only four ingredients: flour, water, salt and a 'starter'.
A starter is a mix of flour and water that has been allowed to ferment. This introduces naturally occurring yeast and healthy bacteria to the mix.
The presence of bacteria creates lactic and acetic acids, which give the bread the sour, tangy flavour.
This mixture is then added to more flour, water and some salt to create a dough and followed by several stages of resting, stretching and folding before leaving it to prove in the fridge overnight. Finally you bake the loaf.
It's altogether a lengthy process and can take one to four days.
With standard bread, baker's yeast is added to speed up the rising process, meaning it's possible to make a loaf in a few hours.
Supermarket sourdough vs bakery or homemade
Sourdough isn't a protected name, so any bread can technically be called sourdough.
So, while traditional sourdough contains only four ingredients, supermarket versions may contain added extras.
Some contain added yeast, which speeds up the process. But many supermarkets have got better about this and now use fermented flour (a starter) instead of yeast.
But supermarket loaves also contain other ingredients not found in traditional sourdough such as vegetable oils, and rice and soya flours.
Rice flour helps to give the loaf a crunchy outer crust and soya flour contributes to a better crumb.
Vegetable oils make the dough easier to handle and extend the shelf-life of the bread by keeping it moist and soft for longer.
Another frequently added ingredient to supermarket sourdough is ascorbic acid. This increases the speed at which the loaf rises and increases the final volume of the loaf.
This means supermarket sourdough can be made in a few hours in the same way a standard loaf can.
In the past some supermarket sourdoughs have contained vinegar, which has been added to create the sour, tangy flavour found in traditional loaves and which is a result of the longer fermentation processes.
You might still find vinegar used in 'sourdough' products such as sourdough crumpets.
Why is sourdough so expensive?
Traditional sourdough loaves can cost upwards of £4 in a bakery. This is because making it is a time-intensive process.
Chris Young from The Real Bread Campaign told us: 'Crafting genuine sourdough bread is a time and labour intensive business. There are a number of factors behind what a small, independent bakery needs to charge for genuine sourdough and other Real Bread, which include supporting more jobs per loaf than an industrial loaf factory.'
A closer look at unit pricing shows that a bakery sourdough loaf might not be as pricey as it looks compared to its supermarket counterpart.
Sourdough loaves from Tesco, Sainsbury's and Asda cost between £1.70 and £1.95 for a 400g loaf, almost twice as much as a standard farmhouse loaf of the same size (£1).
A waste-less sourdough from Gail's bakery (made with 'porridge' from surplus bread to reduce food waste) is £4.50 for a 750g loaf, but that's almost double the size of the supermarket loaf.
When you work out the cost gram for gram the difference isn't quite so stark: 43p to 48p per 100g for supermarket sourdoughs versus around 60p per 100g for the Gail's version.
The Real Bread Campaign calls out loaves using the term 'sourdough' but which actually contain additional yeast as 'sourfaux'. Here are some supermarket sourdoughs which meet their criteria for traditional sourdough. These include:
Is sourdough healthier?
In terms of calories, fibre, fat, sugar and salt, however, sourdough isn't that different to normal bread.
How to make your own sourdough at home
Making your own sourdough is relatively easy and you don't need any fancy equipment, just patience, a proving basket and a lidded casserole pot.
source https://www.which.co.uk/news/article/supermarket-sourdough-what-you-need-to-know-auKKz0t5cn4r