Experiments in yoghurt making

I bought a yoghurt maker on takealot.com on Monday afternoon. It was delivered exceptionally speedily first thing on Tuesday morning.

As the yoghurt maker comes with several jars and these can be used in the machine simultaneously, I decided to test using different substances and starter cultures. Normally one uses milk but I thought cream might also work. However, the fermentation process requires lactose for the bacteria to feed on, which cream has less of, so some of my tests are a 50:50 mixture between milk and cream to give the bugs more food. The starter culture is normally a bit of other yoghurt, but I decided to test mass / amasi (sour milk) too.

So I made the following 7 yoghurts:

1. 100% cream with a maas starter culture
2. 100% cream with a normal yoghurt starter culture (taken from Spar's double cream plain yoghurt)
3. 50% cream, 50% milk with maas
4. 50% cream, 50% milk with yoghurt
5. 100% milk with maas
6. 100% milk with yoghurt (x 2)

The milk is UHT pasterised full cream milk from Spar. So not a bacterium in (microscopic) sight.

Here's a photo of the ingredients and materials, prior to the start. (I used bits of putty on the lids of the jars to be able to identify the recipes used in each one.)

Here are the jars with starter culture blobs inside.

They recommend that you heat the milk to 90 degrees and then cool it to 30 degrees before starting. 

The milk heated well. However, while heating the cream, as the temperature reached about 60 degrees I stopped heating it as it had started to de-emulsify. 

Then the milk and cream went into the fridge to cool to 30 degrees.

And here's the yoghurt maker in action. All it does is provide the amount of heat that keeps bacteria happy and hungry.

The end result looks and tastes pretty much like yoghut. The yoghurt starter culture with 100% milk yielded the thickest result, the 100% cream mixture took a few hours longer and didn't thicken nearly as much, as expected due to the far lower lactose content. So it's probably more accurate calling the result fermented cream instead of yoghurt. It tastes really good. The maas starter faired significantly worse. Next time I'll buy younger maas as I suspect the one I bought probably was too old and had too few live bugs left in it.