Which Acid is Present in Curd? Everything You Need to Know

Published on 06/06/25

(Updated on 06/06/25)

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Which Acid is Present in Curd? Everything You Need to Know

Curd — a staple in almost every Indian household — isn’t just a delicious sidekick to parathas or a soothing addition to a spicy biryani. It’s also a powerhouse of health benefits and curious chemistry. Ever wondered which acid is present in curd that gives it that slightly tangy taste? Or why it’s often recommended during stomach troubles but sometimes avoided by people with acidity? You're not alone. This creamy delight has puzzled and healed generations. Whether you're scooping a spoonful to cool your palate or looking at it as a source of probiotics, there’s a lot going on inside that bowl.

Let’s unravel the science, nutrition, and health facts of curd — and answer the real questions people ask Google every single day.

Introduction to Curd and Its Composition

What is curd?

Curd, known as dahi in Hindi, is a dairy product made by fermenting milk using live bacterial cultures. The process might seem simple — just add a spoon of old curd into warm milk and let it sit — but there's more happening at a microbial level.

Curd isn’t the same as yogurt, by the way. While both are fermented, yogurt is made with specific strains of bacteria and often under controlled conditions, while curd is made at home with naturally occurring bacteria from the environment.

So, no — your grandma's dahi isn't "just yogurt". It's a little more unpredictable and a lot more traditional.

How is curd made?

In Indian kitchens, warm milk is mixed with a bit of pre-made curd, usually from the previous batch. The bacteria — mostly Lactobacillus — begin fermenting the lactose (milk sugar) into lactic acid. This process thickens the milk, curdles the proteins, and gives curd its signature sour flavor.

Here’s the twist: temperature, milk quality, and even the vessel used can affect how the curd turns out. Sometimes it's perfectly creamy, other times, it's watery or too sour. Relatable, right?

Nutritional value of curd

Curd is rich in calcium, protein, vitamin B12, and probiotics (good bacteria). One bowl can help strengthen bones, boost digestion, and even improve mood. Seriously, gut health is linked to mental health — that’s not even a wellness fad anymore, it’s real science.

It’s also low in carbs and can be consumed plain or with rice, sugar, fruits, or spices. In India, people even churn it into buttermilk (chaas) or blend it with fruits for lassi.

Common uses of curd in Indian households

From cooling the stomach in scorching summer heat to applying it on sunburns or even hair — curd does it all. It’s added to curries for a creamy texture, served on the side during meals, or eaten solo with a pinch of sugar or salt.

But curd isn’t just comfort food. It’s been used for centuries in Ayurvedic remedies, digestive aids, and even as a skincare ingredient. Honestly, there’s nothing quite like it.

The Acid Present in Curd

Which acid is found in curd?

The main acid found in curd is lactic acid. That’s the one responsible for its slightly tangy, sour taste and its gut-friendly health benefits. When milk ferments, the lactose (a natural sugar) gets broken down by Lactobacillus bacteria into lactic acid. This acidification process is what transforms plain milk into the soft, creamy, slightly thickened curd we all know and love.

People often search things like which acid is present in curd or name the acid present in curd — and the answer's simple: lactic acid. No need to memorize any long chemical names.

Lactic acid in curd: Formation and function

Lactic acid doesn’t just change the texture and flavor — it plays a huge role in preserving curd naturally. It creates an acidic environment that prevents harmful bacteria from growing, which makes curd relatively safe to consume even in warmer climates (though of course, storing it in a fridge is best).

This acid is gentle on the stomach and actually helps with digestion by encouraging the growth of more beneficial bacteria in the gut. So, yeah — your grandmother was totally right when she said a bowl of curd helps settle the stomach.

Scientific explanation of lactic acid fermentation

Alright, if you like a little nerdy detail, here’s a quick breakdown:

The bacteria used to make curd (mainly Lactobacillus delbrueckii and Streptococcus thermophilus) ferment lactose into lactic acid via a process called homolactic fermentation. This means one molecule of glucose is converted directly into two molecules of lactic acid. It’s a clean and efficient conversion.

This increase in acidity lowers the pH of the milk, causing casein (the main milk protein) to coagulate and form that soft, jelly-like structure — aka, curd. It’s basically edible biochemistry.

Why does curd taste sour?

The sour taste of curd? That's the lactic acid at work. The longer the fermentation, the more lactic acid builds up — and the tangier the curd gets. That’s why curd left out overnight in summer often tastes more sour than one set in cooler weather or refrigerated quickly.

Some folks even prefer this sour curd for making dishes like kadhi or curd rice — it adds depth and zing to the flavor. But for eating plain, fresh curd with just the right tang is perfect.

Health Benefits of Lactic Acid in Curd

Supports gut health and digestion

Lactic acid is more than just a souring agent. It helps increase the number of beneficial bacteria in your gut, which can improve digestion and reduce bloating or constipation. If you’ve ever had stomach trouble and someone offered you curd rice — they knew what they were doing.

Improves nutrient absorption

Probiotics in curd can help the intestines absorb vitamins and minerals more effectively. That means more calcium and iron from your food is actually used by your body.

Boosts immunity

A healthy gut = a stronger immune system. That’s not a typo, it’s fact. And lactic acid bacteria in curd help build that robust microbiome.

Curd and Acidity: Is It Good or Bad?

Is curd good during acidity?

This one’s tricky — and surprisingly, people get confused a lot. You’d think eating curd (which is technically acidic) would worsen acidity, but that’s not always the case. For many people, curd actually helps neutralize stomach acid and soothes the digestive tract. It creates a cooling effect, especially when eaten plain or with rice.

However, not all stomachs react the same. If you already have excess acid production or acid reflux, curd might not be ideal in large amounts. Also, never eat curd at night if you're prone to acidity — it may trigger discomfort or bloating in some folks.

How curd interacts with stomach acid

Curd doesn’t increase stomach acid. Instead, its lactic acid is milder and promotes a healthy gut lining. That said, if it’s too sour or taken in combination with spicy foods, it might irritate an already sensitive stomach.

When to avoid curd during digestive issues

During severe acid reflux or GERD
If curd is very sour or stored too long
If you’re lactose intolerant (though curd is often tolerated better than milk)

In such cases, buttermilk (chaas) is a better choice. It’s lighter, diluted, and less likely to trigger acidity.

Curd in Gastritis and Other Digestive Conditions

Is curd good for gastritis?

In most cases, yes — curd can help soothe an inflamed stomach lining. Its probiotics repair gut flora and its cool texture can relieve burning sensations. Just make sure it's fresh and not too sour. Spiced curd or curd with rice is especially helpful.

Role of probiotics in managing gastritis symptoms

Probiotic-rich curd helps reduce Helicobacter pylori, the bacteria that cause many gastritis cases. Daily consumption (in moderate amounts) may reduce flare-ups and promote healing — just don’t eat it too cold straight from the fridge.

Is Milk Curd Acidic? Understanding pH Levels

pH of milk vs curd

Fresh milk has a pH around 6.5 to 6.7 — pretty neutral. Once it turns into curd, the pH drops to 4.5 to 5.5, making it mildly acidic. Still, it’s not harmful acidic like lemon juice or vinegar. It’s a soft acid that’s generally stomach-friendly.

Does milk become more acidic when turned into curd?

Yes, but it’s part of the fermentation process. The lactic acid formed gives curd its digestive and preservative powers. Ironically, this mild acidity is what makes curd alkaline-forming in the body after digestion. Wild, right?

Common Misconceptions About Curd and Acidity

Does curd help in acidity? Often yes, but depends on the person.
Curd in uric acid patients? Avoid if uric acid levels are very high — talk to a doc first.
Can everyone eat curd daily? Mostly yes, unless you have specific medical restrictions or dairy allergies.

Expert Tips: Best Ways to Consume Curd for Health

Eat curd in the day, not at night.
Pair it with plain rice or make a cooling raita.
Avoid mixing it with fish or very spicy food — causes digestion clashes.
Prefer homemade curd over flavored or packaged ones.

Conclusion

So, now you know which acid is present in curd — it’s lactic acid. But more than that, curd is a humble superfood with deep cultural, culinary, and medicinal roots in India. Whether you’re enjoying it as part of a meal or using it to settle an upset stomach, its benefits go beyond its sourness. Just like every home has its own way of setting curd, each person’s body reacts to it differently. Listen to yours, and don’t be afraid to add a little dahi to your day.