When yogurt and (increasingly) kefir are available at health food stores and grocery stores, some people wonder why one would want to make these things at home. But there are many reasons! Firstly, it’s gratifying to create something that not many people know how to make. You form a new connection to your food and to the ancient cultures that have been making them for generations. Many people like the challenge of getting the tartness, texture, etc. just to their liking, while others get excited about the surprise of what happens when less oversight is used to create something that is otherwise so consistent. Making yogurt and kefir from scratch can greatly reduce your grocery bill. Many DIY-ers (Do-It-Yourselfers) like the control over ingredients that’s possible when making things from scratch. Health-conscious people are interested in the fact that the biodiversity in homemade yogurt and kefir to be superior to store-bought. It’s also fun to share these edible bacteria and yeast cultures with friends and family. Whatever the reason, transforming a common ingredient like milk into something tart, fizzy, biodiverse, thick, digestible, and most importantly, delicious, is a powerful feeling. If you only want to dedicate time and refrigerator space to either kefir or yogurt, it’s beneficial to understand the differences between the two.
There’s a multitude of differences between yogurt and kefir, but I’m just going to keep it simple for the sake of space. The main differences between making yogurt and kefir at home come from the organisms that transform the milk. Yogurt is made using only bacteria, which can be mesophilic (ambient temperature-loving) or thermophilic (warm temperature-loving). New batches of yogurt can be made by using a bit from the last batch (with commercial yogurts, these cultures weaken over time and only last through two to three batches). That being said, yogurt cultures vary greatly on the particular style (Greek, Caspian, Icelandic, etc.) and each culture has a preferred temperature. Most common yogurt cultures prefer thermophilic conditions but some prefer mesophilic. Early human cultures made whatever yogurts thrived in their environment, so it makes sense that Indian yogurts are thermophilic and Icelandic yogurts are mesophilic.
Kefir is made from a symbiotic community of bacteria and yeast (SCOBY, which is similar to what kombucha is made from) that is mesophilic. The SCOBY grows larger during every batch, and pieces of it can be given to friends and family so they can start their own. Many commercially available kefir starters are bacteria-only and do not form the charming little blobs that are characteristic of SCOBYs shared among friends.
The main things to consider if you want to try making one of these at home are ease and texture. Kefir has a slightly more yeasty flavor, but the flavor between yogurt and kefir are otherwise pretty similar. By far, kefir is easier to make because all you need to do is put the kefir SCOBY in pasteurized milk, stir occasionally, and wait about 24 hours. Kefir’s texture is thin and drinkable, and can even be slightly fizzy. Milk soda! Some people prefer the thickness of yogurt, but it needs to be incubated for 8-12 hours at 105-115 degrees F (except for mesophilic strains, which take 12 to 24 hours at room temperature). Mesophilic strains tend to be runnier than thermophilic ones, so there’s no way to get around heating the milk and incubating it if you want the thickness. Both yogurt and kefir can be strained to create a thicker texture (that’s how Greek yogurt gets its extra thickness).
Now that you know the key differences between the two, try making them both and see which one you like more!