You may not realise it, but you’ve probably eaten fermented food this week. Maybe it was curd with lunch, dosa for breakfast, or pickle alongside dinner. Fermentation sounds like something from a science textbook — a process done in a lab with safety goggles and gloves. But it's actually one of the oldest food practices in the world, and plays a big part in everyday Indian cooking.
The last 10 years or so have seen an increased interest in the technique, with kombucha and kimchis making their way into kitchens. Despite its current trend, fermentation has been a staple in many kitchens. The technique is as old as time. It's found naturally in nature, with humans discovering its benefits — both health and taste-wise.
Payal Shah, the founder of Kōbo Fermentary, has been fermenting for almost 25 years. What started as an interest in making ginger beer at home eventually transformed into Kōbo - a lab for all things fermentation. Dubbed the Shephard of Microbes for her immense knowledge of the process, she also works as a guide for anyone curious about fermentation. Among her workshops and masterclasses, Shah also hosts a weekly AMA (Ask Me Anything) on her Instagram, where she addresses questions about fermentation. Now, in its sixth year, her questions range from the technicalities of the process to examining home ferments and the ever-pressing question “Has this gone bad?”
What Is Fermentation?
When asked for a simple explanation of what fermentation is, Shah’s responds that “Fermentation is magic. It's microbes doing magical things to our food to make it delicious. It also does other things like improving nutrition and shelf life. But very importantly, it adds flavour.”
The more technical explanation is that fermentation is what happens when tiny microorganisms (usually bacteria or yeast) work on the sugars and starches in food. These microbes break them down, and in the process, create something new. This process takes place without oxygen, usually in a sealed jar or a covered bowl.
No lab, no special equipment — it just comes down to time and the right environment.
These microbes have been doing this for thousands of years, long before anyone had a name for it.
Fermentation is perhaps more common than most people realise. Shah lists the common examples of idli, dosa, pickles, and curd; everyday food things that we’ve been eating for decades. Fermentation is what gives these foods their sourness and airy texture. She also points to food like sandige (also known as vadam or vadiyalu), sun-dried pickles, and curd-soaked vegetables. Recent years have seen a spotlight on how widespread fermentation is in India.
Fermentation has been deeply ingrained not just into Indian culture, but across the world. According to Shah, it's a process that has been happening naturally for millions of years. There are many stories of how animals like elephants, squirrels, and monkeys get “drunk” on fermented fruits.
As humans, the discovery only came about 12000 years ago. She shares an ongoing joke that fermentation was discovered by “some brave person who decided to try something that looked interesting, smelled interesting, and didn't die.” The discovery was about how microbes work on food naturally, and the understanding that if the environment is right, it ferments. And if it isn’t, it rots. The discovery also led to playing around with flavour, as the technique developed alongside agriculture — and things like bread and beer were then created.
In addition to the flavour, fermentation was also a way of preserving things in times before refrigeration. Eventually, the nutritional benefits were also observed.
Fermentation FAQs
As a part of Shah’s weekly AMA, she has had every possible question about fermentation. She helps us tackle some of the most common ones:
1. How can someone tell the difference between food that's fermented well and food that's just gone bad? How do I know if it is fermenting properly?
“When food goes bad, it will
smell bad. We say in fermentation to use your senses. So, if something looks
bad, for example if it's growing mould or looks fuzzy, then that's not a good
sign. But as you ferment more, you will see patterns of different ways these
microbes show. And if something looks okay, then you smell it, and if it smells
good, then it is also likely to taste good. Fermentation is older than any
best-by dates or lab testing. This is how our ancestors have done it for
thousands of years - trust your senses.
If it's bubbling, if it smells
good, and especially if it tastes good, then you know that your ferment has
been successful. The biggest indicator to look out for is mould.”2. What's the most common myth or misconception about fermentation?
“Maybe all the health claims
attached to it. There definitely are benefits, but it requires a lot of
research to understand the nutritional and lifestyle effects. There’s a lot
that needs to be taken into consideration, and there's no cookie-cutter answer,
because all our guts are very different from each other's.
Another myth is that
fermentation is dangerous and not safe. It is safe. You just have to do it
right to get to know your microbes. It’s extremely exciting and very, very
rewarding. I hope I've been doing a good job at trying to educate around that.”3. Is there anything people get unnecessarily anxious or scared about fermented foods/the fermentation process?
“I think it's all the
nutritional effects, which need a lot more research. Especially for gut health,
it is something people get anxious about, but that’s something they should talk
to a doctor about.
Another common anxiety is about
the fermentation process. I think one thing that people should be careful
about, not necessarily anxious though, is just remembering to burp your
bottles. Especially in warm temperatures if there's a lot of wild yeast activity
going on, burp your bottles because you don't want bottle bombs.”Note: Burping your bottle means releasing the carbon dioxide naturally produced by microbes. It involves carefully unsealing the lid to hear the gas escaping, and then immediately sealing it back up. This is essential to prevent the pressure buildup, which can lead to a messy opening or glass breaking. Think of it like shaking a fizzy soda versus gently opening the lid.
4. Why does fermented food smell different?
“It smells different because
it's the microbes doing their work - fermenting the things that are in your
jar. They are eating that up and producing these compounds. The smell is from
the acids that are released, which we also refer to as like postbiotics.
These compounds and nutrients,
like B vitamins and dead yeasts, are the things that are good for us - for our
neurotransmitters, for our guts, for our hormones, et cetera - the chemical
balance that goes on in our bodies for them to function well. So the microbes
in our jars are doing the same things that they are doing in our guts.
They are almost pre-digesting
the foods that they are fermenting. We are smelling these strong-smelling
compounds, like lactic acid or acetic acid or other things that are being
produced.”5. Are all fermented foods supposed to taste sour?
“No, not necessarily. Fermented
foods can range from mildly tangy to quite sour. It depends on the fruit or
vegetable you start with; some might be naturally more sour than others.
Fermentation happens in two
stages. One stage is where the microbes break down the sugars in the food that
you're fermenting. In the second stage, all those sugars are converted into
acids - that's lacto-fermentation. The sourness increases in this second half
of the fermentation.
So, there is some amount of
sourness that increases as the fermentation happens. This is also true for
yeast-based fermentation. You start with something that's quite sweet, and as
it ferments, it becomes more and more sour, going all the way to vinegar, which
is really, really sour.
Take sour dahi (curd), for
example. The sourness doesn’t mean that the dahi has gone bad; it just means
that the microbes have used up all the sugars they feed on, and they’ve run out
of their food. When you use a little of that curd to make a fresh batch with
milk, the microbes get a new food source - and it won’t be as sour.
Sourness is like a scale; it
changes during fermentation. How sour a food tastes will depend on when you eat
it."6. Can fermented food go bad?
“Yes, it can.
The long answer is that
fermentation itself is a method of preservation. So one of the things that it
does is extend the shelf life of whatever you are fermenting. But some things
have a shorter shelf life, while other things have a much longer shelf life.
Like vinegar, wine, or soy sauce, it never goes bad; it just keeps getting
better as it ages. But some things like idli and dosa batter, or dahi, don't
have a very long shelf life- it will last maybe a week.
You can see mould on your dahi,
or your dosa batter will start smelling funky after a certain point. So yes,
your ferments can go off. It's just about using them at the right stage of
fermentation for that particular dish.”7. Can I make fermented foods at home?
“Yes, absolutely - you can make
fermented foods at home. People have been doing this all over the world for
thousands of years.
And, in fact, you absolutely
should be fermenting because it does so much to our food in terms of flavour,
in terms of nutrition, and in terms of extending its shelf life. Everyone
should be fermenting whatever they can. You can get excited about the magic
that microbes can do.”8. Do I need special equipment?
"No, not at all. All you need is
a few empty jars and any ingredients that you already have in your kitchen.
Fermentation existed long before any sort of special equipment or any
technology or any refrigeration.
Just start with whatever you
have in your kitchen, and you can see as you go.”Shah called fermentation magic — and in a way, it is. It's an ancient process, one that's been making food last longer and taste better for far longer than we've understood why. It might sound like a complicated technique, but really, it's something that happens every day, in foods most of us eat without a second thought.
