I’ve been making yogurt for a few months now, from a batch that one of my (wonderful) Indian co-workers brought me of her strain from India. Just today, my best friend Sally took home some of my yogurt so she could start making it, too. So, I’m writing down directions.
Here’s how I make yogurt:
- I make sure to keep at least a tablespoon of the previous batch of yogurt. The instructions I was given were that one tablespoon is enough to make the next batch of yogurt, no matter how much you’re making. I haven’t tried this too closely, I’ve been making 1-2 cups with one tablespoon of yogurt.
- I’ve been using a glass container, but you could use plastic or stainless steel (I hear Indian stores have fabulous stainless steel containers, but I haven’t managed to go look yet).
- Put the tablespoon of yogurt into the container, then fill the container with milk. If I make two containers of yogurt, I use one tablespoon of yogurt per container. I’ve been pouring the milk in cold, straight out of the refrigerator, but see my notes below about the proper Indian method.
- Put the container with the yogurt in a warm place. I’ve been putting it in the oven with the oven light turned on. I’ve also been using a thermometer to gauge the temperature in the oven (not in the milk/yogurt), and have found that it’ll go above 100°F. I’m not very scientific about it, so I leave it in the oven with the light on for several hours, until it’s above 100°, then turn it off for several hours until it’s at 80° or lower, and then turn it on again, etc., until it acts like yogurt. I after I turn the light off the second time, I’ll usually leave it in overnight.
- Once it’s wobbly like yogurt, take it out, put a lid on, and stick it in the fridge. I haven’t been worrying about leaving it in the oven too long, and if I’m not sure it’s ready I’ll leave it in a bit longer.
My theory (and I haven’t done any research about this) is that yogurt bacteria like to be pretty warm to grow quickly. It could be that getting the milk even warmer than that would be helpful, and then you might not need to leave it out part of the day and all night.
Proper Indian directions, per my coworkers who looked at my like I was crazy when I described how I’d made yogurt (I haven’t ever followed these directions*):
- Heat up milk in a pot until boiling.
- Take it off the heat, and let it cool off until it’s just warm.
- Pour the milk into containers, with a tablespoon of yogurt per container. Put in the oven with the light on only if your home is fairly cold. (I’m not sure about the technical definition of that, but I’d guess 70° is nearing too cold.)
- Let it sit for about 8 hours.
- Cover and refrigerate.
My theory about why my method is working just as well: Milk bought in the U.S. (>99% of it, anyway) is already pasteurized. Boiling it is like pasteurizing it. So here in the U.S. it’s an unnecessary step. Therefore, the only actual need is to warm up the milk. Maybe warming it on the stove or in a microwave would work better than putting it in cold, but it would take more steps before I could move on to the next thing in my day. I’ll let you know if I ever try it.
What’s the difference between Indian** yogurt (or any kind of home-made) and store-bought? Many things. First, home-made yogurt is made up of hundreds of bacteria that are good for your digestion, whereas store-bought uses just a few strains that each company has decided are the “best”, or maybe patentable. Even the brands that advertise that they have live cultures only have a few very specific live cultures… and the strains may have been added in after the yogurt became yogurt. Indian, or any kind of home-made, yogurt is yogurt because it was made with all of the strains of bacteria that were in the culture to start with. (By the way, you probably could start yogurt from store-bought, as long as it’s the kind that has live cultures, but then it wouldn’t have very many strains of bacteria. If you can find someone who has their own yogurt, that would probably would best.)
Second, home-made yogurt can vary quite widely in flavor, depending on what bacteria are in it. The strain I have is a bit sweet, even when left plain. Others can be very sour.
Third, because the beneficial bacteria in home-made yogurt are still alive and active, they don’t leave room for harmful bacteria to grow. This doesn’t mean it can’t spoil, and I’ve been told to keep it in the refrigerator once it’s made (this also keeps it from getting more sour-flavored), but it’s less likely to go bad.
* I don’t follow directions well. Also, I was given yogurt before I was given instructions. And then I decided to try it, based on what I know about kefir and what I’d heard about yogurt. I guessed wrong, but it worked anyway.
** Other cultures make yogurt, too. Only my Indian coworkers have told me about it, though, so that’s my point of reference.