Crockpot Yogurt--More than you ever wanted to know

It's my turn to join the chorus of blogs about making yogurt in your crockpot all referencing this blog. It was really funny. I started out to look up making yogurt in your crockpot because I heard about it somewhere and that was the top of the Google list. I checked it out and even tried it. Then I went back to the internet to find more information and the next 5 links I looked at were all someone else's blog pretty much directing you to the first one. I did finally find some helpful notes on how it actually worked for someone else on this blog, and then I found this non-blog article with some more technical information which really helped my yogurt making skills.

Some people are afraid of plain yogurt because it is not actually yummy all by itself. But just mix in a spoonful of your favorite jam, or some frozen berries and a little sugar, or just have it with fresh fruit and it is delicious. You can also use it as a substitute for sour cream or to give something you would normally put milk in a little zip. It is versitile and healthful. For my figuring of the nutrition information and cost comparison of home made yogurt, see the bottom of this post.

Without further ado, here are my chronicles (and ultimate triumph) of home made yogurt (and also I've been wanting to make bulleted lists on my blog for a while, so I am seizing the opportunity):

Attempt # 1:
I was so excited to try this when I finally got around to looking it up and it looked so simple that I was impatient and didn't want to wait til we went to the store and I could buy some plain yogurt. I tried to talk myself out of it, but I finally succumbed and decided to use what I could scrape off the top of the one last fruit-on-bottom Greek yogurt cup my sister had bought from Costco.

The Procedure:

• 2 quarts (Costco) non-fat milk, heated it in the crockpot on low for 2.5 hours.
• Turned off the crock pot and let it sit, covered, for 3 hours.
• Stirred 2 packets of Knox unflavored gelatin into cold yogurt scrapings.
• Stirred 2 c. lukewarm milk into yogurt.
• Stirred yogurt mixture into the rest of the lukewarm milk.
• Wrapped the crock in a thick towel and let it sit overnight.

The Results:
It was minimally successful and I have since learned that my milk did not get hot enough to start with and didn't stay warm enough during the culture process and so it was very thin and sort of gloopy. After refrigerating, the gelatin congealed and it was a little bit disturbingly like goopy milk-jello (2 packets for 2 quarts is too much). This would have lead my sister to completely bag the idea of homemade yogurt, but I persevered. Attempt #2:
I looked up other blogs to see if I could find more tips. I decided to try full fat yogurt, as I was sure it would be easier to get it thick without added ingredients. I figured the cultures in the yogurt I made would still be good, even if the yogurt was gross, so I used it as starter for my next attempt.

The Procedure:

• 2 quarts whole (Costco) milk, heated in the crockpot for 2.5 hours
• Turned off crockpot, cooled, covered, for 3 hours.
• Stirred about 1.5 c. milk into about 3/4 c. funky homemade yogurt-jello-gloop.
• Stirred back into milk.
• Put into an oven heated at 145 deg. for 15 minutes then turned off.
• Left the light on in the oven for a little added warmth during the night.
• Left in the closed oven til morning.

The Results:

OK. It was thicker and richer, but still not incredibly thick. We ate it. The kids loved it, and I saved 1 c. for starter next time.

Attempt # 3

This was the point where I learned about the actual temperatures that the milk is supposed to get to. This made a huge difference. I used a meat-probe type thermometer, the kind you are supposed to jab deep into your roast, or turkey, or what-have-you. I dangled it in the milk covering as much of the shaft as I could to get the reading. I discovered that 2.5 hours on low was way not enough to get the milk up to the 180 degrees it is supposed to get to to begin with. Also that it can cold down to the 110 degrees it needs to be not to kill the yogurt cultures a lot faster than 3 hours. So I made some adjustments to the original method.

The Procedure:

• 2 quarts fat-free milk heated in crockpot on high for 4 hours to 180 degrees
• Removed crock from cradle, cooled, uncovered, 1 hour to 110 degrees
• Made the mistake of trying to mix the skin that had formed back in.
• Forgot and mixed 1 c. starter yogurt directly into the milk without tempering it.
• Heated the oven to the lowest setting of warm--145 degrees--for about 15 minutes.
• Checked the temp. of the milk--about 100 degrees
• Turned off the oven and put the crockpot, covered, in side
• After 1 hour, checked the temp of culturing milk--less than 110 degrees
• Turned on the oven to 145 again for 15 minutes (with the crock inside)
• Turned off the oven, checked temp--about 120 degrees
• Waited 1 hour, checked yogurt temp--I can't remember what it was.
• Noticed that the yogurt definitely looked like it was congealing in the middle with clear-ish liquid around it. When I stuck the thermometer in, I was definitely sticking it into something--I couldn't swish it around easily.
• Let it sit one more hour, checked temp.
• Reheated oven for 15 minutes, then turned off
• Let sit another 2 hours

The Results:

This was the most set up I had yet achieved. In my checking of the temperature I remember it being as low as 100 and as high as 135, mostly in the higher range. I decided to drain the yogurt through a coffee-filter lined wire mesh strainer (actually several strainers--you can't fill any of them too full or they don't drain completely). about 5 cups drained out in whey--a clear, thickish, yellowish liquid that is as sour as yogurt. 3 cups was left of thick, creamy, beautiful, delicious fat free yogurt. It was very sour and I realized that the yogurt was probably done at least 2 hours before I took it out. It cultured very quickly when it was kept warm enough. There were also small papery pieces throught it, I believed to be remnants of the skin formed while cooling that I tried to mix back in. I have not had this problem since I started removing the skin.

Attempt #4:

I wanted to see if, having successfully kept it warm in the oven, I could actually just leave the oven on warm and it would culture just as well.

The Proceedure:

• 1 quart fat free milk, heated in crockpot 4 hours to 180 degrees
• Removed crock, cooled 1 hour, uncovered, to 110 degrees
• Removed the skin from the top and discarded.
• Mixed 1/2 c starter yogurt into the milk.
• Preheated the oven to 145 degrees
• Put in the crock, left the oven on
• Periodically checked temp. It got to 145 degrees after maybe 45 minutes.
• Cultured for 3 hours--the length of time it was actually done in last time
• Removed from the yogurt from the oven, spooned it into coffee filters to drain
• Noticed the yogurt was not smooth--sort of grainy.
• Thought, "Oops. I think I cooked it."
• Lots of whey drained off.
• Transfered the "yogurt" to cheesecloth instead of coffee filter so I could press it out.

The Results:

What was left was sort of rubbery and squeaky, like new cheese. It was a little sour, but not as sour as yogurt usually is. But since it was not salted, it wasn't very tasty. It may be worth experimenting with in the future to make cheese on purpose. It was not good yogurt. Luckily, I still had some starter yogurt left.

Attempt #5:

I was fairly confident in my yogurt making skills by this point, even though the last time was a fail. I decided to go for mass production so I wouldn't have to make it so often.

The Procedure:

• 1 gallon fat free milk, heated in the crock pot for 4.5 hours
• Cooled for about 1 hour
• Mixed in about 1 c. yogurt
• Heated oven for 15 minutes, turned off and put in crock
• After 1 hour, turned on oven for 15 minutes.
• Let culture for 2 more hours, then--done!
• Drained the yogurt through coffee filters in strainers and collanders.

The Results:

After draining for a couple of hours, I was ultimately left with 10 c of whey and 6 c of Greek-style (thick) yogurt. It was perfect and wonderful and now I am a yogurt making master. Thank you.

Attempt # 6:

This was made exactly like #5 except that I ended up using cheese cloth to drain it instead of coffee filters and I was able to put it all in one strainer instead of lots of them and it drained just fine. I was tired of the counter full of bowls and strainers and all of the used up coffee filters that got thrown away. I tiny amount of yogurt was lost in being stuck in the cloth, but not much more than stuck to the filters. I rinced the cloth and it dried very quickly. It should be able to use it over and over again. I like this plan.

I found lots of advice on what to do with the whey. I haven't actually tried any of these except using it in a little bit of baking:

• Use it to culture your next batch of yogurt instead of the yogurt itself.
• Put in a little sugar and drink it (like lemondade).
• Water your plants with it.
• Feed it to your pets.
• Use it in place of buttermilk in recipes (or in place of milk+vinegar in recipes, but not in place of fresh milk alone--it will make things sour).
• Wash your face with it--like a yogurt scrub spa treatment.
• Make bread with it (because of the sugars in it, you might be able to cut down on the sugar you add to feed the yeast).

For most of the suggestions that use it as a replacement for milk, I personally wouldn't want to because it is lower in protein than regular milk but has the same amount of carbohydrates. But that's just me. Others may not care.

Summary of tips:

• In figuring out how to make it in your crock pot, go off of temperature, not time--your individual crock as well as the volume of milk will all make a difference in how long it takes.
• If you don't have a thermometer, 180 degrees is when it starts to look frothy and like it is moving without being stirred, but not boiling. It has a distinct "cooked milk" smell that fresh milk does not have. 110 degrees feels like a hot tub--initially very hot, but you get used to it. You would not put a baby in it.
• The starter yogurt does not actually need to be tempered by mixing a little hot milk into it before mixing it back into the whole body of milk. If it is hot enough to kill the yogurt it is too hot period. If it is not, tempering it won't make a difference. I don't temper any more.
• The more starter you use the faster it will culture.
• The warmer the better (faster) for culturing, as long as it does not exceed 140 degrees.
• If you want a thinner, drink style yogurt, check periodically during the culture process and stop (refrigerate it) once the desired consistency is achieved. It is not necessary to culutre it completely if you don't want to.
• There is no need to continue culturing it once it is gelled. It will only get more sour and not less watery.
• The more fat in the milk, the thicker the yogurt will naturally be.
• You can add thickeners to low or fat free yogurt if you don't want to drain it. Some suggestions are unflavored gelatin, powdered milk
• The yogurt will thicken in the refrigerater, so don't despair if you don't want to drain it and it isn't quite thick enough for you to begin with.
• I started taking out the starter before I drain it and putting it in a separate container in the fridge so it doesn't get used by accident--1 cup per gallon.
• If draining off the whey with coffee filters, only do a thin layer at a time. Otherwise what is next to the filter thickens and creates a barrier so the whey on the top/in the middle is blocked in and won't drain out no matter how long you let it sit. This doesn't seem to be a problem when using cheesecloth.
• If you still like the flavor variety available in commercial yogurt, try mixing commercial yogurt half and half with homemade plain yogurt. The commercial stuff is so extra sweet that I actually like it better once it is dilluted, and it makes the more expensive stuff last twice as long!

Funny story for those of you who persevered all the way to the end:

While this last batch I made was left to cool uncovered, my brother in law stopped by to look at it. "Um, Carol? Your milk is breathing." I came over to look and sure enough, it had formed a skin on top, but was still hot enough that the milk underneath was swirling and roiling and making the skin wave and pucker and shimmy. It was really facinating to watch.

And now the promised nutrition info:

Undrained: The nutrition info for 1 cup is the same as for 1 cup of whatever milk you used. This will vary with the fat content, but for fat free milk is 0 grams fat, 13 grams carbohydrates, 9 grams protein.

Drained (removing 2 quarts from 1 gallon): I read that the nutrition content of the whey is o grams fat, 13 grams carbs, and 2 grams protein. If draining off the whey you are losing the entire amount of carbohydrates for every cup of whey drained off, but only 2 of the 9 grams of protein, which means 7 grams of protein are left for each cup of whey drained off. This means each remaining cup of Greek-style thickened fat free yogurt has 13 grams carbohydrates and about 20 grams of protein.

Cost Comparison:

The other blogs I read all used expensive products for price comparisons. I buy cheap stuff (not organic milk or yo-baby), so that's what my price comparison reflects. About the absolute cheapest you can find yogurt is $1.50 for 1 quart--$0.375 per cup, when it is on super sale. One gallon of fat free milk regularly costs about $1.90 at Costco, which is what we always get. This works out to $0.119 per cup of undrained yogurt (disregarding the cost of starter, which fades out after the first couple batches and any thickener you may choose to put in it), or $0.473 per quart. Even when drained, it comes out to $0.317 per cup of Greek style yogurt. That's crazy savings, especially when you figure that greek style yogurt actually sells for at least $1 for 6 oz, even on sale.

So the moral of the story is: Everyone should make their own yogurt. It is easy and so, so cheap.

(For additional insight, some of which supercedes what I thought I knew at the time of this writing, please see An Addendum on Yogurt and More (Concrete) Yogurt Insights.)