1. I believe kefir is usually the same consistency as buttermilk, not yogourt. How do you make them as thick as yogourt?
2. How do you keep your kefir grains alive? I don't use a huge amount of yogourt. Can you freeze grains between uses? How often do you need to make a new batch to keep the grains alive?
When not in use I just put the jar in the fridge (as long as it's only been at room temp for <24h) and it can stay there for weeks slowly getting more sour. At some point the kefir becomes too sour to be palatable, but will recover just fine after a feeding or two. I also keep backup grains in water in the fridge for years and have revived one of those after 5 years or more! Apparently the grains can also be dried and revived after years as well but I haven't tried that.
There's lots of info about milk Kefir on Dom's Kefir In-Site (straight from the nineties web!):
It's usually just a 5-10 minute affair for me to strain out the fermented kefir and add a new pack of milk to the grains.
I used to use dedicated yogurt culture, but "kefir yogurt" tastes exactly the same to me, so I use it for everything (yogurt, goat cheese, kefir-the-drink, obviously).
Here's some more info: https://www.chelseagreen.com/2021/natural-yogurt/