HOT sauces are popular all over the world. Many are produced by fermentation, using microorganisms to add depth of flavour and create sauces offering more than just a kick of chilli heat.
The burning sensation comes from capsaicin, a molecule that activates heat receptors. As Clare Wilson explained in her science of gardening column a fortnight ago, Capsicum plants may have evolved the ability to produce capsaicin to deter mammals from eating them, but our species has developed a perverse taste for the pain it brings.
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If you are following Clare鈥檚 tips for growing chillies at home, you might have a bumper crop ready for turning into fermented hot sauce. If not, making it with shop-bought chillies is just as rewarding.
The basic idea when fermenting any kind of food is that you add salt to encourage certain microbes to grow and produce acid. The salt and the acid inhibit the growth of bacteria that cause food to spoil, so fermented foods tend to keep for many months.
In fermented cabbage dishes like kimchi, bacteria that produce lactic acid, such as Lactobacillus and Leuconostoc, are key players in the process. But this isn鈥檛 the case when fermenting chillies, . They found that acetic acid and malic acid were the main acids in chilli fermentation.
The researchers found over 100 volatile compounds 鈥� those that are easily vaporised and reach our noses 鈥� in the fermented chillies. These included 43 esters, a class of molecules known for their fruity aromas, that became dramatically more concentrated during the fermentation process.
Through genomic analysis, the researchers then identified Rosenbergiella and Staphylococcus as the most dominant types of bacteria in the fermented samples, but little is known about how they contribute to flavour. They also found a diverse range of fungi, including the yeasts Hyphopichia, Kodamaea, Meyerozyma and Debaryomyces, which are found in other fermented foods such as sourdoughs and cider vinegar.
To make your own fermented hot sauce, you can use any kind of chillies you like 鈥� ideally ones that haven鈥檛 been treated with pesticides. It is a good idea to taste them first rather than spend two weeks fermenting only to discover that your sauce is too hot.
After removing the stalks from your chillies, pack them into a sterilised jar with the garlic. Dissolve the salt in the water, then pour this into the jar too, making sure the chillies are submerged. Now, seal the jar and leave it at room temperature for one to two weeks, opening it every few days to let gas escape.
When the chillies taste sour, your ferment is ready. Strain it, reserving the liquid, then blend the solids while adding enough liquid back in to make a smooth sauce. Add sugar and vinegar to taste 鈥� then store in the fridge.
What you need
300g red chillies, stalks removed
50g garlic, peeled
500ml water
25g salt
1 tbsp sugar
1 tbsp cider vinegar
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