Homemade Yogurt

Since I have become an evangelist for homemade yogurt in the real world, I've decided to create a blog post for my online world about how easy it is to make yogurt.  We've been making our own yogurt for about 8 months now. We've had mostly successes and a few failures and have learned a few tricks along the way to make it easy for this full time working mother of 3 to make homemade yogurt several times a week.

So the basic procedure:
1)  Bring 1/2 gallon of milk nearly to a boil
2)  Let it cool off
3)  Add a "starter" of previously made yogurt
4)  Let it sit for about 12 hours until you have yogurt

Honestly, it is that easy: (nearly) boil, cool, starter.  People have been making yogurt for nearly 4,000 years.  Seriously. During that time, people have made a lot of mistakes.  (Well, at least I have in my last 8 months) And yet there has never been the great Yogurt Death of 2400 BC. Or 800 AD.  Or 2012. Millions have people have made yogurt, and you can, too!  Plus, call me ethnocentric: you are on the computer, you drive a computer and probably have a smart phone.  Plus, you easily understand what zero is, which at one point was revolutionary among the greatest mathematical minds. You are smarter than the people from 4000 years ago and YOU CAN MAKE YOGURT.

So here is some additional information until this process turns into "(nearly) boil, cool, starter."

1)  We heat our milk in the microwave in a glass bowl covered with a glass plate because the clean up is a boatload easier than doing it on the stove.  Cleaning a pot of milk heated on the stove sucks.  There is no clean up of heating milk in a glass bowl.

Milk in glass Bowl

2)  You want to bring the milk to over 180 degrees to kill any bad stuff and make something good/funky happen to the milk proteins.  (See the history of yogurt)  This really means, get to boiling but not quite.  However, if you step away and/or forget what you are doing and the milk comes to a rolling boil, that is still ok.  You can still make yogurt and you should. It just won't be as smooth.

3)  We microwave our yogurt on high between 12 and 13 minutes depending on which glass bowl we are using.  You can use an instant read thermometer to check the temp to get over 180.

4)  We let the milk cool uncovered for between 50 minutes and a hour to get back down to 110 degrees.  This is cool enough to stick your finger in the milk for 10 seconds so it doesn't hurt but it still feels hot.  I got that trick from Make the Bread, Buy the Butter.

5)  Add between 1/4 and 1/2 cup yogurt with active cultures.  This can be from a previous batch or a batch you've bought from the store of plain yogurt.  The more starter you add, the quicker the current batch thickens up.  I just put in about 1 cup of starter because I want a big batch for tomorrow and there wouldn't be enough leftover for my breakfast yog AND to make the next batch.  So I just added it all.

Starter Yogurt in the other glass bowl we use

6)  Now it's time to let your yogurt, um, yogurt-ize.  In the summer, we just covered it and let it sit on the counter for 12 hours.  In the fall, we started wrapping it in a towel to let it stay warm more easily.  In the winter, after a couple of way-too-water-y yogurts, we started wrapping it in a towel and putting the bowl in the oven, which has been ever so briefly warmed at the lowest temperature we could go.  We turned the oven on the lowest temperature (170) until it preheated and then turned it off.  The whole point was to get it warmer than room temperature before we put the yogurt in.

Wrapping the yogurt in a towel

7)  You can let the yogurt sit longer than 12 hours.  I've seem some advice to let it sit for 18 hours if you want it to be thicker and I accidentally let it sit for 22 hours the other day and we didn't die after we ate it.  Remember:  4000 years of yogurt making.  Mistakes have been made and things still turned out ok.  I think there must be a wide margin of error on yogurt making for it to have survived this long.

8)  For me, I think it's ready when there is some liquid on the top of the yogurt (the whey) and the rest of the yogurt looks solid-ish.  If the yogurt and whey not separated, we let it sit a little longer.  If it's longer than usual, I think it means you're yogurting at a lower temperature or not enough starter, so hang loose and weight a bit more.

12 hours later....

9)  We pour off the whey, save it in the fridge and use it in our next batch of homemade bread.  When we first started making yogurt, it was still a bit more liquid-y than the store but we were ok with that. (Remember, there are stabilizers in store bought yogurt)  Now that I wrap it in the towel and put in the oven, it's pretty solid and has the same thickness as store bought yog.

We've poured off the whey

10)  To make Greek yogurt, drain your yogurt in some cheesecloth for a couple of hours.  You will get a TON of whey and yummy, creamy, tasty, CHEAP Greek yogurt.

11)  We use non-fat yogurt because I am trying to lose weight, but you can use whatever you'd like.

12)  Once, I let it cool too much and there was a skin of milk on the top.  I didn't take it off before I started the yogurtizing process and there were some gross, plastic-y bits in the yummy, creamy bits of the yogurt.  Now I take the skin off if there's a lot of it.

So that is it.  You have all the detailed information that I have gained out of our "(nearly) boil, cool, starter" cycle.  If you have any additional questions, leave them in the comments and I will update this post.  It still feels like magic every time I make yogurt.  If you can boil water, you can make yogurt.  And yet we pay TONS more than we need to by buying all this yogurt in the store!!  I did a little math last night and using 2 quarts/week of yogurt, saving $5/week (at least), we're saving well over $260/year.  Just saying.

I am the yogurt evangelist!  Get thee to the microwave and start your own (nearly) boil, cool, starter cycle now.

UPDATE:  A friend has found that leaving the oven light on keeps the oven temp at 110 degrees, the perfect yogurtizing temperature!!

Updated Update: We have changed  what we do.  Microwave 13 minutes. Cool for 60 to 75 minutes.  Add 1/4 to 1/2 starter.  Put  in oven with light on, no towel for  at  least 16 hours  (usually noon until 6 am next day, so I  can't  really do  math).  No draining and thick, greek yogurt.

Updated Update to the Update: To make the perfect Greek yogurt, we use this strainer: