So I tried it, following the instruction on
this web site.
At the suggested temperature it took a long time to dehydrate. By long I mean over 24 hours. It quickly turned into a sort of gummy fruit leather but getting it to a drier state was so very slow. Removing the result from the fruit roll-up sheet was also a lot of work. The blade coffee grinder made quick work of it, turning it into a sticky powder.
The web site suggested 2:1 or 3:1 ratio of water to powder but this was way too runny. I ended up using something closer to 1.3:1. I waited and waited for it to fully dissolve but a certain grittiness remained even an hour after mixing it with cool water. But it was kind of like yogurt in consistency; maybe a cross between yogurt and thin hummus.
The taste? Oh, well, it wasn't that good. The overwhelming feature was a kind of tartness that was not so pleasant. The sweetness was hard to discern and the vanilla flavor was only a memory.
Now it could be the yogurt I chose wasn't appropriate. The web site mentions that some yogurts work better than others. I prefer runnier yogurts than what used to be standard yogurt. In fact, it is sometimes referred to as "Australian style" yogurt, which is ironic now that strained, so-called "Greek" yogurt has taken over most of the shelf space in supermarkets, including in Australia. Also, I eat non-fat yogurt and that may have also had an important effect. And since it was a vanilla flavored yogurt there was added sucrose. The ingredients were nonfat milk, sucrose, vanilla and cultures. Anyway, that's what I started with, a local organic yogurt that is wonderful when fresh. Dehydrated and reconstituted it was like the instant coffee of yogurt.
I won't be doing that again.