I permanently borrowed my mom's "vintage" Salton Cosmopolitan yogurt maker several years ago. I go in spurts, sometimes making several batches in a row before relegating it to the cabinet. The instructions (dated 1976) say to boil the milk in a saucepan, let it cool to 110°, add starter, pour into the glass cups, and let it do its thing for 10 hours. (Roadblock: Afternoon naptime is not a good time to start this process.)
My friend Elizabeth found a method to use the crock pot to make yogurt, but her batch didn't turn out. I've read that homemade yogurt is sometimes runnier than storebought, but mine historically thickens up, perhaps because I've added powdered milk to make it creamier. Recently I've read opposing viewpoints about the potential heart hazards of oxysterols, so I figured omitting it is easier than becoming an expert.
Heating the milk in a microwave is one way to speed up the prep. (I haven't found a consensus online regarding microwaves and their effect on nutritional value. Some people say you will probably die if you microwave food, others say it's no different than heating on the stovetop. Some say the vitamins are inactivated while the minerals (calcium) are kept. I microwave.) You still have to let the milk cool to 110° before adding starter (I use a spoonful of existing yogurt). The other morning I decided to do a batch of yogurt on account of being ahead of schedule. One thing lead to another and we were then running late to playgroup, so I didn't let it cool properly, added starter at like 150°, and 10 hours later found out I ruined the batch. (Come to find out that is the temperature for vat pasteurization - oops - I killed the necessary bacteria. So maybe a crock pot operates too hot for yogurt, since a typical slow cooker is designed to heat food to 170° on low.)
I was reading online about various ways to make your own yogurt, from the primitive (a bowl in the oven with the pilot light on) to the fancy. One guy with a yogurt maker (which, in my opinion is more like an incubator since you do all the work beforehand) mixed a spoonful of yogurt (starter) into cold milk, put it directly into the cups/machine, and got fantastic results when curing was finished. Brilliant! It made sense to me since milk is already pasteurized, so I had to try it.
This time I used just two jars to lower the potential waste, put whole milk and 1/2 tsp yogurt in each as starter. One came out runny like milk, and the other was yogurt-firm on top and creamier below. I had that one for breakfast today and it sure tasted like yogurt, and now I have a good reason to buy a new yogurt maker.
1. Buy new yogurt maker. Am considering canister model which eliminates need for cups.
2. Test temperature of old yogurt maker. Depending on results, sell unit or parts on eBay or just use milk glass cups as vases.
3. Buy cheesecloth. Make yogurt cheese.