My kefir is sitting on a seedling mat so it keeps it in the low 70s temp.
For fermenting kefir (or starting tomorrow veggies) I use these nifty little silicone inserts I put in the top of the mason jars. 10 bucks for half a dozen. These have a tiny (invisible) slit in the top (that you make sure to crack open by pushing up from underneath on the middle before using). When the CO2 gathers it escapes by pushing up until the tiny crack opens. So no opening/tightning jars.
For strainer I got this nylon mesh set. $10 for four sizes
(I needed a strainer anyway)
And 90# cheesecloth is recommended if you're doing a big long strain to make cheese https://www.amazon.com/gp/product/B072V18F5L
(No, I don't work for amazon haha, but it took me awhile to find this stuff so I thought refs might be helpful even just to see examples)
I have mason jars in every size that are a wide-mouth lid, so everything I get is to fit wide mouth mason jars. Most grocery stores actually sell these although if you live in an area with thrift stores they also often have some, you can just get new lids.
I tossed my first three batches as 'recovery' mode.
My first 'real' batch ('adaptive' phase I call this, for a dozen or so more cycles) finished cycle 1 (I call it the 'hot' cycle, active culturing with the grains) on counter on mat in half gallon jar with 6 cups [org grassfed non-homog pasteurized whole milk in that case]) yesterday and is currently in cycle 2 (which I call the 'warm cycle' because now it is without grains, but still on the counter). I have cinnamon in one, cocoa in one, and a little swerve sweetener in all three, as an experiment. I shook them this morning as the CO2 had displaced the additions to the top. I will put them in the fridge shortly for cycle 3 (the cold cycle) and I will taste it again, add whatever might be needed still, and hope to leave them about 3 days in the fridge and then drink.
I'm interested in the chia pudding idea. I don't know how many carbs are in chia. But coffee and cocoa and sweetener added to dairy sounds simply fabulous to me!