The origins of kefir are lost in time; however we know it comes from the Caucasus where people have used it for centuries. The word kefir comes from the Turkish word keif which means good feeling or feeling good.
Kefir grains were a valuable and well protected treasure kept by the Caucasus Mountains’ natives, which is why it was unknown to the rest of the world until the beginning of the 20th century.
Kefir is a drink obtained by fermenting soy, cow, goat or sheep's milk. It thrives in temperatures ranging from 10ºC to 25ºC. A culture of lactobacilli and yeasts, known as kefir grains (white or yellowish gelly-like grains) feeds on milk. It is also known as yoghurt plant, yoghurt mushroom or yoghurt flower.
Because kefir grains don't stop growing due to constant fermentation, traditionally they were passed on from one person to another as an offer. Maintaining the grains for several years demands that kefir is prepared almost daily or that special care is taken regarding its conservation while away on holidays or if you just want to stop taking it for a while. Kefir can be frozen for a certain amount of time, but needs to be brought back to life after a few weeks. Due to these reasons, dehydrated kefir cultures are now for available with all the benefits of the traditional fresh grains and more practical for the modern consumer, therefore providing an interesting option for any busy person of the 21st century.
Kefir cultures contain healthy bacteria for the human organism, which is why it is considered a probiotic food like yoghurt (although each of them contains different bacteria, kefir bacteria are also able to colonize the intestinal tract). According to the World Health Organization, “probiotics are living organisms that, when taken in adequate quantities, are beneficial to the host's health.”
The value of kefir lies in its aminoacid quality and quantity as well as in its effect on regenerating the intestinal flora, stimulating natural defenses. It contains healthy digestive bacteria which inhibit the development of other pathogenic intestinal microorganisms, therefore preventing infections (particularly, intestinal ones).
Comparing several scientific studies on kefir, some authors from Allama Iqbal Open University in Paquistan conclude that the regular intake of kefir is beneficial for the antimicrobial activity, intestinal health and anti-cancer activity, controlling glucose and cholesterol levels and strengthening the immune system. 
How to prepare kefir
1. Bring 1 litre of milk to a boil or use freshly made milk from your soy milk maker and let it cool until it reaches room temperature. As an alternative, open a new milk carton.
2. Sterilize a glass bowl and a spoon. Run them under boiling water, thus destroying bacteria that could interfere with the reproduction of lactobacilli.
3. Pour the milk into the bowl and add a whole sachet of kefir culture (or kefir grains) to it. Stir well.
4. Cover the bowl with a lid or cloth but allow air to circulate in order to free the gas produced during the process.
5. Let the culture grow at room temperature for 24 hours.
6. Keep the drink in the refrigerator for a maximum of 12 days. Kefir which is prepared with kefir culture has a low acid level at low temperatures (if you use the fresh grains, the drink becomes a bit tarter after a couple of days).
7. To make a new batch, just use 4 tablespoons of the kefir you already made (no more than 3 days old) with a litre of milk. You can repeat the process up to 10 times before using a new sachet of kefir culture. If you use the grains, you should drain them from the liquid and add them to more milk. Always repeat the process. Do not wash the grains, because the balance of the bacteria colonies can be affected.
How to use kefir
Kefir can be taken by anyone (except lactose or soy intolerants in case you use animal milk or soy milk to prepare kefir) and is very useful for athletes and children.
The beverage prepared with kefir grains or kefir culture has a creamy, thick and uniform texture with a light tart taste similar to yoghurt.
Kefir can be taken plain, added to smoothies or used like yoghurts, for example mixed with muesli, goji berries, chia seeds or fresh fruit.
You can also prepare a pate (like cream cheese) and use as a spread for bread. Just add a pinch of salt and herbs (oregano, for example) and drain the kefir’s serum for a few hours using, for example a tofu kit coated with a cheesecloth.
To benefit from kefir’s healthy properties, use it only in cold recipes because high temperatures destroy lactobacilli.
Insert date: 2013-03-10 Last update: 2013-06-21
Authors > Contributor writers > Cristina Rodrigues
Authors > Translators > Ana Soares