What is Sourdough

We are big fans of sourdough at Vicky’s Bread and use it in almost all of our products. It has become hugely trendy in the last decade, and probably rightly so, but the frequency with which the term is thrown about can leave us feeling a bit confused. Why is this sourdough stuff so amazing? Is sourdough better for me? Does bread have to be a sourdough to be good? Will all sourdoughs taste the same? And what is a bloody sourdough anyway?!

What is sourdough?

A sourdough culture is a mix of flour, water and natural yeast cells living in the flour and in the air. This mixture is left to ferment, and when it is sufficiently active and filled with bubbles of gas, it can be used to leaven (rise) bread. Bread made with a sourdough culture to leaven it instead of commercially produced yeast is called a sourdough loaf, or just a sourdough. 

So when someone says ‘sourdough’, it is not always clear whether they are talking about the culture or the finished bread. The French say “levain” when they’re talking about the sourdough culture, and “pain au levain” when they mean sourdough bread, which is more helpful. 

Most people name their sourdough cultures, as they can feel rather like owning a pet; ours is called “twelve”, and we have several different twelves made with different flours. Our spelt sourdough culture is used for the spelt sourdough bread, and we use a wholewheat sourdough culture for our wholewheat sourdough loaf. Mostly, we use a sourdough culture made with organic white flour, and we have three large vats of it bubbling away in the bakery every day. 

It is entirely possible to use both a sourdough culture and commercially produced yeast in the same bread, and sometimes it’s a very helpful thing to do. We do this a lot. We make our multigrain bread with quite a large amount of sourdough culture and a small amount of commercial yeast as well. The dough contains so many seeds that the loaf needs some extra leavening help from the commercial yeast. Using the extra commercial yeast allows us to make the loaf much more seedy and therefore nutritious than if we relied on a sourdough culture alone to rise the bread. Sourdough culture is a more dilute form of yeast, and so in some circumstances it might be necessary to add commercial yeast to achieve the result you want, and in my book that is absolutely fine, as long as you are honest about it of course! 

What is so great about sourdough?

Using a sourdough culture to leaven bread has some fantastic advantages. A sourdough culture is naturally acidic, as it produces organic acids and ethers as it ferments. This increases the acidity of the final loaf, and this has a number of effects. Firstly, it naturally lengthens the shelf life of the bread without using artificial preservatives. Secondly, it strengthens the gluten structure, allowing us to make a wetter, looser dough, resulting in a dough that is more moist. Thirdly, the acidity developed during a long fermentation and proof improves the flavour of the dough. 

The use of a sourdough culture encourages our body to extract more of the minerals and goodness from the flour as we digest the bread. Phytic acid, which is found in wheat bran, interferes with our body’s ability to absorb all the lovely nutrients in the wheat, in particular calcium and iron. Brilliantly, a sourdough environment neutralizes almost all the phytic acid, leaving us able to absorb all the nutrients we can.

A lot of people find slowly fermented breads easier to digest and much kinder to the tummy. As a sourdough culture is a more dilute form of yeast, it forces the baker to slow down and wait several hours or overnight for the dough to rise and ferment. I often liken the fermentation of a bread dough to cooking a white sauce; it is important to properly cook the flour in a white sauce, or it is raw and hard to eat, and so it is with a bread dough; without a lengthy fermentation, the finished loaf can feel cakey and hard to digest. 

So, in conclusion, I think we can say that sourdoughs live up to the hype and really are great!

Does bread have to be a sourdough to be good?

No. There are other ways to make a flavourful, slow-rise loaf, such as using a biga or poolish, which is just using a bit of commercial yeast and mixing with some of the flour and water from your recipe and leaving this to ferment for a few hours. Sometimes, we don’t want that tangy sourdough flavour, and there are lots of lovely breads that aren’t sourdoughs. 

However, using a sourdough is arguably the best way to deepen flavour, naturally lengthen shelf life and help our bodies to get the most nutrition from the bread. A sourdough culture forces us to slow down and let the dough properly ferment, so it is generally a better product…. BUT, it does still have to be made with good quality flour, mixed lightly, moulded gently and by hand, and given the time it deserves to be a great bread. It is possible to find a bad sourdough, so beware!

Is a sourdough bread better for me?

Generally, yes. But the benefits of a sourdough culture need to be weighed up against the other attributes of that particular loaf. Does the bread contain added sugar or fat? Are there wholegrains or seeds to boost the nutritional and fibre content? What about the quality of the flour? And has it been made slowly with no shortcuts? Using a sourdough culture is an important element of a loaf, but it’s not the only thing to consider. A beautifully made artisan loaf does not have to be a sourdough to be delicious and healthy.

Will all sourdoughs taste the same?

A big no. 

Firstly, the sourdough culture itself varies hugely in flavour. Both location and the type of flour used will affect the culture. 

Each microbial community produces its own flavour profile, so sourdough cultures will be different all over the world. Some produce more lactic acid, giving a more creamy, yogurty flavour, and in others there may be more acetic acid which results in a tangy-er, more vinegary taste. 

I find our wholewheat sourdough loaf, made with a wholewheat flour sourdough culture, is tangier and wheatier than our gentler Bordelais sourdough loaf, which is made with a white flour sourdough culture. Our spelt flour sourdough culture is even more lemony, verging on the vinegary, and our rye culture is deep, nutty and super tangy as well.

The finished loaf will therefore taste unique to the place it was made and the flour it was made with, which I think is rather exciting. The bad news is that if you want to taste a genuine San Francisco sourdough, you are going to have to get on a plane!