After Mike Smolyansky, 40, and Edward Puccosi, 43, emigrated from the Soviet Union, one of the things they missed most was kefir. A cultured-milk product similar to yogurt but slightly effervescent, kefir (pronounced kuh-fear in Russian) is more popular in the Soviet Union and Eastern Europe than Coca-Cola is in America. So two years ago, the men, now in Chicago, set up a company called Lifeway to make and distribute kefir.
Made by fermenting milk with grain from the kefir bushes that grow in the Middle East and southern Balkans, the drink until recently was available in the U.S. only in...