Kefir gone crazy.

My kefir is out of control. It’s been super sour and the consistency is very grainy. So I took all but about a tbsp of grains out and I’ve been doing a second fermentation. Seems to be helping but today I came home to my secondary ferment all over the counter and when I opened the lid, it overflowed out of the jar.

Any kefir tips?

Looks like it has separated into curds and whey. This is usually because your grains are too high a percentage to the milk. Your kefir is just too strong and is working very quickly. The kefir is forming faster than desired and then over culturing by separating into curds on top and whey at the bottom. Doesn't seem like anything is wrong and that is why it is extra sour.

Just reduce the amount of grains or add extra milk or slow it down by putting it in a cooler location. Or use it faster.

Anything I can do with it once it separates like that?

if you mix it back up and then strain it, it should be a drinkable consistency. If too sour or a weird texture, just sift the grains and start a new batch.

Wow, Miranda! That is an active culture! I agree with what everyone else said. I usually do about a teaspoon of grains for every 2 cups of milk. But that's just my culture and it's pretty young. You might need to use even less grains. Also, if you have a higher percentage of cream in your milk, it cultures faster, so reduce the cream content if you can. And check it often! Yours must be ready in a few hours! As soon as the consistency changes from liquidy milk you have to check often.

It is super active! That picture was from after I strained the grains and let it ferment some more.
I got these grains from someone who had extra so they have been going a while. I’m just starting so it’s been a lot of trial and error this week!

I agree with the others about reducing the amount of kefir grains to try and settle things down. One thing I want to ask is are the grains fermenting at an average room temperature like 70-78f or is the jar somewhere warm, like on top of the fridge for example.

I keep my house cool in the winter, 60 at night and 68 when my wife and I are home, and I have to double up my kefir grains to get a pint of milk to ferment in 24 hours, but now that things are warming up and my house temp is approaching normal summertime upper 70's indoor temperature, it takes much less grains to get the same fermentation.

I'm honestly not sure what the temperature is in our house. We don't have a thermostat on right now (only comes on when we turn the heat/ac on and it's nice right now so we aren't using it).  I would guess it's around 70-73.  Could be higher though as before we moved here, our thermostat was usually at 76 and I was comfortable.

I've reduced the grains down to about a teaspoon but it is still separating. It seems a bit better but not great. I think my next attempt at a fix will be to double the amount of milk maybe. I'm hesitant to do that though because I'm already making more than I really need. But I suppose if I can get it to a good consistency, maybe I can find someone at work that would like some on a daily basis...Open to suggestions.

Cultures for Health has lots of articles for troubleshooting milk kefir grains. Here's a good article with some others linked in it. Another option is to make kefir "cheese" given how active your culture is. Here is an article about how to make that. I hope that helps!