Please consider the fact that yogurt makers are made to re-culture yogurt. Thus, you can make yogurt with ready-made yogurt, activated by the manufacturer, as a starter, or use a second batch easily and for very short time.
These yogurt markers will definitely produce the first batch(mother culture), but in order to activate the starter or make the first batch, you need to give it more time, due to the stages of fermentation.
These are different for the first batch and the second one.
In general, the second batch sets quicker and it is much more predictable when it comes to timing because it skips the first stage of fermentation, which takes longer to set.
So, to make sure that everything works out right, always use whole milk, free of preservatives and additives. Then, depending on the maker you use, follow these tips:
Electric yogurtmaker with many jars – please remove or leave the lids loose, to improve temperature distribution;
The single jar yogurt making devices have a better temperature distribution, as everything is one single place, so just allow time to ferment – you do not have to do anything else.
If you use a non-electric yogurt making device or any kind of hot water flask – please change the water with a slightly hotter one after 8-10-12 hours, if the yogurt has not set and it needs more time. Do not use boiling water, as it can kill the bacteria at this stage and ruin your yogurt.
If you use a traditional method with no device – please add one or two bottles with very hot water next to the container with the yogurt mix and wrap them with thick towels or a blanket. Then place it in a warm spot and replace the bottles when the water gets cold, after 8-10-12 hours.
When you re-culture the milk with a ready yogurt or kefir as a starter, you do not need to do any of the above, as fermentation is much quicker and it will be completed after just a few hours.
For more info, please visit our website, blog, forum, and YogurtApp, or check out the videos which will explain the fermentation stages and other aspects.