Exploring the world of kefir, from its health benefits to its unique fermentation process.
Exploring the world of kefir, from its health benefits to its unique fermentation process.
Related links:
https://culturesforhealth.com/
Welcome to the Nutrition Diva Podcast! I'm Monica Reinagel, and today I want to answer some great questions I received from long-time listener Anne Marie, who wanted to know more about making kefir and how its benefits compared to yogurt.
Fermented foods like kefir have been gaining popularity, in large part due to the explosion of research on the human microbiome — the community of microorganisms living in our bodies — and the benefits of probiotic foods.
Probiotic foods contain beneficial microorganisms that can inhibit the growth of harmful pathogens, enhance digestion, and synthesize valuable nutrients such as B12 and vitamin K. There are thousands of different strains of probiotic bacteria, and eating lots of different kinds of fermented foods can give you exposure to a wider array of benefits. Beside kefir, fermented foods include yogurt, sauerkraut, kimchi, miso, tempeh, and kombucha. Each brings its own unique benefits, bacteria, and flavors to our diet.
I also want to distinguish between the bacteria in probiotic foods and the resident bacteria in our gut–because this is often misunderstood. Probiotic foods help maintain a healthy balance in our digestive system, but the bacteria that they contain don't necessarily become permanent residents of our microbiome. Instead, they pass through our system, helping out along the way.
If you’re interested in fostering that resident population of microbes, then your best play is to eat plenty of fiber from a variety of sources–beans, legumes, whole grains, fruits, vegetables, nuts, seeds, and so on. The fiber in these foods provides a food source for those resident bacterial populations, and the better and more varied a diet we feed them, the healthier and more varied they are.
With that context, let’s talk more about kefir.
Kefir is a fermented milk drink that’s believed to have originated in the Caucasus Mountains, where its been part of the traditional diet for hundreds or even thousands of years. It's made using kefir grains, which are a mix of proteins, sugars, bacteria, and yeasts, known as a SCOBY (a symbiotic colony of bacteria and yeasts). These grains likely came about by chance, discovered by nomads who carried milk in animal skins, leading to natural fermentation.
Although it dramatically altered the flavor and texture of fresh milk, fermentation also greatly extended its shelf life without refrigeration. Early kefir consumers learned to strain the grains out of the soured milk and use them to ferment the next batch. These living colonies — gelatinous, walnut-sized blobs resembling cauliflower florets — were carefully nurtured, often passed down through generations.
Like other fermented foods, kefir promotes gut health, boosts the immune system, and helps regulate the body’s inflammatory responses. However, kefir also has some unique benefits that set it apart from other fermented foods:
Kefir offers a more diverse microbial composition than other fermented dairy products like yogurt, thanks to that SCOBY. It also contains a unique polysaccharide called kefiran, which contributes to its anti-inflammatory and antimicrobial properties.
The presence of yeasts in kefir leads to the production of small amounts of alcohol and carbon dioxide, resulting in a slightly fizzy drink. While commercially produced kefir is processed to remove the alcohol, home-brewed kefir can contain anywhere from 0.5% to 2% alcohol, depending on fermentation time. The fizzier it is, the more alcohol it contains.
Full disclosure: Kefir can be an acquired taste. If you enjoy drinking buttermilk, you’ll probably also enjoy unsweetened kefir. For those who find it too sour, it can be flavored with pureed fruit or vanilla extract, or used in smoothies. It can also be used in place of milk or buttermilk in things like muffins and pancakes and to add a sourdough-like tang to breads or pizza crust. Like any probiotic food, however, heating kefir above 110 degrees Fahrenheit or so will kill the beneficial bacteria and yeasts and diminish its probiotic benefits.
Now, how does kefir compare to yogurt? Both kefir and yogurt contain lactobacillus bacteria, which digest lactose in milk and produce lactic acid, giving both products a tart flavor. If you're sensitive to lactose, kefir might be easier to digest, as its fermentation process can break down more lactose than yogurt. But both will contain comparable amounts of protein and calcium.
In terms of texture, yogurt is usually thicker and can be eaten with a spoon, while kefir is more like a drink. So, whether you prefer the spoonable texture of yogurt or the refreshing fizz of kefir, both can be nutritious additions to your diet.
Traditionally produced kefir typically contains dozens of different bacteria and yeasts. Commercial producers, on the other hand, use a limited number of carefully selected species to create a more consistent product. But some health benefits ascribed to kefir may depend on the more varied cultures found in traditionally fermented kefir.
Fortunately, making kefir at home is easier than you might think and can be simpler than making yogurt. Unlike yogurt, which requires heating the milk and maintaining a specific temperature, kefir ferments at room temperature. No special appliance is necessary, making it a convenient option for home fermentation.
To start, you'll need kefir grains–the living mix of bacteria and yeast that ferment the milk. You can find kefir grains online, at health food stores, or sometimes from friends who make their own kefir, as the grains multiply and can be shared.
To make it, you simply add fresh milk to the grains—this can be cow, goat, or sheep milk, non-fat, reduced-fat, or whole. However, because you will not be sterilizing the milk before fermenting it (the way you would if you were making yogurt), use only pasteurized milk. Also be sure that the container you are using to ferment is scrupulously clean.
You’ll cover the jar with a clean cloth or paper towel and secure it with a rubber band. Leave the jar on the counter at room temperature for 24 to 48 hours. The milk will thicken and develop a tangy flavor as it ferments. If you like a milder flavor, opt for a shorter fermentation.
Once the kefir reaches your desired taste and consistency, strain the mixture through a mesh strainer to separate the kefir grains from the liquid. The liquid kefir will keep in the refrigerator for 7 to 10 days. When you’re ready to make your next batch, place the strained grains back into a clean container and add fresh milk.
As long as they have regular access to a fresh food supply (i.e., milk), the grains remain viable indefinitely. In fact, you could end up making the kefir faster than you can consume it. If you’re not ready to make your next batch immediately, you can store the strained grains in a small amount of milk (just enough to cover them) in the refrigerator for up to ten days. When you’re ready to use them again, discard the milk they’ve been stored in and start over with fresh milk. If you need to store them for longer than ten days, pop them in the freezer. To revive them, add a bit of milk for them to snack on while they thaw.
Making kefir at home is straightforward, but there are a few challenges to be aware of. The consistency and flavor of homemade kefir can vary from batch to batch, due to variability in the microbes present in the milk and your kitchen environment. (Even if I share my colony of grains with you, the kefir I ferment on my counter will not be exactly the same as the kefir you brew in your kitchen.)
The diverse population of microorganisms in kefir grains can also change over time and with different conditions. This makes it challenging to quantify the exact probiotic or alcohol content of homemade kefir. But if you’re a frequent kefir consumer, making your own can save you some money and it gives you the satisfaction of nurturing a living culture.
Water kefir is another fermented beverage made with a SCOBY but instead of fermenting milk, you ferment sugar water or fruit juice. You’d need a different SCOBY than the one you’d use for milk because the bacteria in a milk kefir SCOBY specifically like to eat the lactose in milk. Water kefir is obviously dairy-free and has a lighter, more refreshing taste. On the other hand, it does not contain any protein or calcium and it will obviously be higher in sugar.
In the show notes I will include a link to one of my favorite online resources for all things related to fermenting and culturing foods. It’s a good place to get a SCOBY if you don’t have a local source but it’s also a really good source of information, instructions and tips for home fermenters
Thanks to Anne Marie for her question. If you have a question you'd like me to answer, you can email me at nutrition@quickanddirtytips.com. You can also leave me a message at 443-961-6206
I’d also like to invite you to check out my other podcast. It’s called the Change Academy, where we explore the art and science of creating positive behavior change, both in our own lives, and in our workplaces and communities. You can find it on all the major podcast platforms. Just search for Change Academy.
Nutrition Diva is a Quick and Dirty Tips podcast. Our awesome team includes Brannan Goetschius, Nathan Semes, Davina Tomlin, Holly Hutchings, and Morgan Christianson.
That's all for this episode. Thanks for listening! I'll see you next week.