Sourdough is crusty on the outside and chewy in the middle.
Millions of people attempted to perfect the loaf during the coronavirus lockdown, including many celebrities like actor Jake Gyllenhaal and reality star Khloe Kardashian.
And while the bread is made with just three ingredients – flour, water and a little bit of salt – there are compounds behind its complex flavor and unique smell.
A team at the Technical University of Munich in Germany has now used science to uncover the 21 essential chemical compounds that give the bread its tangy taste and sweet, mild vinegar smell.
These include salt and lactic acid for taste and molecules that smell like butter and fresh-cut grass for the unique aroma.
The researchers believe it could also help artisan bakers create more consistent sourdoughs for customers to enjoy.
![A team at the Technical University of Munich in Germany has now used science to uncover the 21 essential chemical compounds that give the bread its tangy taste and the sweet, mild vinegar smell](https://i.dailymail.co.uk/1s/2023/08/16/21/74399119-12414545-image-a-11_1692218268823.jpg)
A team at the Technical University of Munich in Germany has now used science to uncover the 21 essential chemical compounds that give the bread its tangy taste and the sweet, mild vinegar smell
To the uninitiated, traditional sourdough — which can be traced back an astonishing 14,000 years — is made using what’s known as a ‘starter culture.’
This contains flour, water and naturally occurring lactic acid bacteria and yeasts (in the flour), which act as the raising agents and make the loaf grow.
This starter is developed into a dough by adding more flour, water and salt, letting them react with the starter, and repeating this several times over one to three days before baking the loaf.
The new study looked deeper to see what compounds are working in the background and found 10 key ‘tastants’ and 11 key ‘odourants’ combined into a sourdough ‘essence.’
Salt (an ingredient added to the bread mix) and acetic and lactic acid (resulting from fermentation) were the critical components of the unique sourdough taste.
Other taste compounds include potassium to add a bitter flavor, ammonium, chloride, magnesium, calcium, d-fructose and l-glutamic acid.
![Millions of people attempted to perfect the loaf during the coronavirus lockdown, including many celebrities like actor Jake Gyllenhaal](https://i.dailymail.co.uk/1s/2023/08/16/22/74400767-12414545-image-m-21_1692221285146.jpg)
Millions of people attempted to perfect the loaf during the coronavirus lockdown, including many celebrities like actor Jake Gyllenhaal
The odorants include acidic with cheesy smells, acetic acid, butyric acid and 3-methyl butyric acid, and a pungent cheesy smell and vanillin (vanilla).
The team also identified hexanal, which gives off the aroma of fresh cut grass, the buttery-smelling 2,3-butanedione (buttery) and the phenylacetaldehyde, which has a sweet, honey-like scent.
Also among the results were 3-methyl butanal with a fruity or cocoa smell, methional and (E)-2-Nonenal with vegetable or cucumber scents and decadienal for the nutty aroma.
To uncover these hidden wonders, the team used an updated version of a ‘sensomics’ technique to sourdough bread crumbs – the soft inside part of a loaf.
Sensomics is considered the cutting-edge science concept to molecularize flavor entities of nature
Laura Eckrich, a graduate student in Prof Hofmann’s lab, said: ‘With sensomics, you can take just a few key compounds and completely recreate the characteristic taste of a food.’
She said the approach involves chromatography, mass spectrometry and similar methods, allowing them to isolate, identify and quantify the flavor compounds in sourdough bread crumbs, then determine which ones were the most important.
![Kloeh Kardashian also baked sourdough bread during the lockdown](https://i.dailymail.co.uk/1s/2023/08/16/22/74400819-12414545-image-a-20_1692221278611.jpg)
![And while the bread is made with just three ingredients - flour, water and a little bit of salt - there are compounds behind its complex flavor and unique smell](https://i.dailymail.co.uk/1s/2023/08/16/22/74400765-12414545-image-m-19_1692221272917.jpg)
And while the bread is made with just three ingredients – flour, water and a little bit of salt – there are compounds behind its complex flavor and unique smell.
The research team then applied a technique known as ‘unified flavor quantitation,’ previously developed by Hofmann’s team, to the sourdough bread.
The process allowed them to analyze the unique taste and aroma compounds simultaneously.
They then used the method in brand-new studies to quantify the concentrations of the compounds in different types of bread.
The researchers also analyzed the best way to reduce bread’s salt content.
They addressed the issue by unevenly distributing saltier doughs throughout a dough mixture.
Since bread, especially sourdoughs can contribute significantly to a person’s daily salt intake, the team said the method could help reduce the amount of sodium while maintaining the bread’s unique taste.
The researchers say their findings should be welcome news for the baking industry.
‘This was the first time bread crumb’s key taste and aroma compounds were elucidated using the sensomics approach,’ said Eckrich added.
‘We hope what we learned will help bakers create the best sourdough bread they can.’