Yogurt and Fermented Foods Explained: How They Are Made

What fermentation means

Fermentation is one of the oldest food techniques in the world. In simple terms, tiny living organisms, usually bacteria or yeast, go to work on the natural sugars in a food. As they do, the food changes. It may turn tangy, fizzy, savory or sour, and its texture often shifts too. Bread, cheese, vinegar, chocolate and coffee all rely on some kind of fermentation along the way.

People discovered the technique long before anyone could see microbes. Cooks noticed that milk left in a warm place thickened, that shredded cabbage packed with salt turned sour and that soybeans could become a rich paste. Those discoveries gave rise to food traditions on nearly every continent, and many of them are still alive in family kitchens today.

How yogurt is made

Yogurt begins with milk. The milk is warmed, then mixed with a small amount of live cultures, which are specific kinds of bacteria chosen for the job. The mixture is held at a gentle, steady warmth for several hours. During that time the cultures turn some of the milk sugar into lactic acid, which makes the milk thicken and gives yogurt its pleasant tang.

• Plain yogurt: just milk and cultures, with a tart, creamy taste.
• Greek-style yogurt: strained to remove some of the liquid whey, which makes it thicker.
• Drinkable yogurt: thinner and sold in bottles for easy sipping.
• Plant-based yogurt: made by culturing nut, oat, soy or coconut bases.

At home, cooks use a yogurt maker, a warm oven with the light on or an insulated pot to hold the temperature. The result is fresh, mild yogurt that you can flavor however you like.

Lactobacillus acidophilus as a food term

If you read a yogurt label closely, you may see a list of cultures. Lactobacillus acidophilus is one of the names that sometimes appears. The word Lactobacillus refers to a large group of rod-shaped bacteria that make lactic acid, and acidophilus means acid-loving. Food makers add certain cultures to yogurt, kefir and other dairy foods because of the flavor and texture they create.

This is simply a general explanation of a food term. Different brands use different cultures, and the label tells you what a particular product contains. The SodaMelt label also lists Lactobacillus acidophilus among the ingredients in its proprietary blend, and you can see the full Supplement Facts panel on the bottle. We cover the whole list on our SodaMelt ingredients page.

Homemade yogurt is a rewarding weekend project. Heat the milk, let it cool until it is comfortably warm to the touch, whisk in a spoonful of plain yogurt that contains live cultures, and keep the mixture warm and undisturbed. Resist the urge to stir. After several hours it will set, and a night in the refrigerator firms it up and mellows the tang. Save a spoonful of the batch to start the next one, and you have a small kitchen tradition of your own.

Flavor is where personal taste takes over. A longer culture time makes a tarter yogurt, while a shorter one tastes milder. Fresh fruit, a drizzle of honey, toasted nuts or a pinch of cinnamon can change the same tub into a dozen different snacks.

A tour of fermented foods around the world

Once you start looking, fermented foods are everywhere. Here is a short tour of popular examples.

• Kefir: a tangy, drinkable cultured milk with a thin, pourable texture.
• Sauerkraut: shredded cabbage fermented in salt, popular in Central and Eastern Europe.
• Kimchi: a Korean staple of vegetables such as napa cabbage, seasoned with chili, garlic and ginger.
• Miso: a Japanese paste of fermented soybeans, often used in soups and glazes.
• Tempeh: a firm Indonesian cake of cultured soybeans, sliced and pan-fried.
• Sourdough: bread leavened with a fermented starter of flour and water.
• Pickles: cucumbers soaked in brine, though vinegar pickles are made differently.

When shopping, read the label. Some jars and pouches are refrigerated and list live cultures, while others are shelf-stable and have been through a process that stops fermentation. Neither is right or wrong; it just depends on what you want in the kitchen.

Enjoying the flavors

Fermented foods are flavor builders. A spoonful of kimchi lifts a bowl of rice, miso gives soup a savory depth and plain yogurt is a flexible base for sauces and snacks. Here are a few easy ideas.

• Swirl plain yogurt with fruit and a sprinkle of oats for breakfast.
• Blend kefir into a smoothie with banana and berries.
• Stir yogurt with herbs, lemon and garlic for a cooling sauce.
• Add sauerkraut to a sandwich for crunch and tang.
• Whisk miso into warm broth just before serving.

For help building balanced plates, the USDA MyPlate site lists dairy and dairy alternatives among its food groups and offers plenty of everyday ideas. Our weekly meal plan guide shows how a tub of yogurt can anchor several breakfasts and snacks in a single week.

Keeping it fresh at home

Cultured foods keep best with a little care. Keep them in tightly closed containers, store them in the refrigerator unless the label says otherwise, and check the date. Use a clean spoon each time rather than double-dipping, which keeps the next serving tasting fresh. If you ferment at home, follow a trusted recipe and use clean jars and utensils. The U.S. FDA Dietary Supplements page offers general background on how supplements are regulated, and it is a useful companion if you like to understand labels in the pantry and in the supplement cabinet alike.

SodaMelt is a dietary supplement in capsule form, and the bottle directions are one capsule daily with about 8 oz of water, alongside healthy eating, hydration and regular activity. Our how to take SodaMelt guide explains the daily routine in more detail.

Fermented foods show how patience and a little warmth can turn simple ingredients into something wonderful. Whether you stir a jar of yogurt or open a crock of kimchi, you are taking part in a very old tradition. When you are ready to see the current price and offer, Check today's offer on the order page.