That said, how much of a commitment is this? If I generate a gallon of kefir in a week, decant off the bulk of the kefir from the grains, and start a new batch immediately, is there something I am missing with regards to the process and maintenance of the grains? I can let the grains sit for a few weeks or even a month in kefir?
It's actually pretty simple and not much of a commitment. But it's a little different from what you describe.
Rather than keeping something going continuously and decanting what you want to drink at the moment, you ferment a given amount to a desired level of "doneness" and strain the grains out. You then refrigerate the kefir and start a new batch with the grains.
If you want to take a break, you can cover the grains in milk and stick them in the refrigerator. I think the longest I've done this is 3 weeks, but longer may be ok.
I've read that stainless steel should be avoided, so I use a plastic strainer that I bought at a dollar store and strain into a glass bowl that I already had. I don't know if stainless steel is really a problem, but since the strainer was only a dollar, I didn't think it was worth taking a chance.
I like mine to be pretty tart, so I let it ferment until there's a visible separation and a layer of whey. If you don't like it as tart, you can strain it sooner.
I use 1 quart canning jars and cover them with a paper napkin held on with a rubber band. When I started, I was using pint jars, but as the grains multiplied, I was able to step up to larger jars. In the summer, I usually do the strain and replace every day or so. I keep my house pretty cool in the winter, so it ferments more slowly. So I keep a couple of jars fermenting. I could also use more grains, but keeping a second jar fermenting just seems easier to me.
As the grains multiply, when you get to a certain point, you'll probably want to use a smaller amount of them in a jar. The extras can be used in smoothies, or you can save them for the future. If you're going to save them for a few weeks, you can just put them in a jar, cover them in milk and store them in the fridge.
For longer term storage, you can dry them for several days at room temperature. If you want to start kefir from dried grains, you need to rehydrate them first. To do that, you cover them with milk and let them sit for a few days. That first batch may or may not be good, so it's best to throw it out. Then repeat the process. Note that although I've given people dehydrated grains, I've never gone through he rehydration process myself, so you may want to read up on it before doing that.
The easiest way is probably to find grains locally (I don't think you can get grains to form by using a starter from commercial kefir, although you might be able to make a batch or 2 that way). I found my grains locally through a classified ad site that's similar to Craigslist, but run by a local news station (it was well established here before Craigslist even got started, so Craigslist never took hold in Utah). Mine were fresh. I think that initially, it took a couple of days to get even a pint, but as the grains multiplied, the time went down and then the volume increased.
If you can't find grains locally, you can also find them online (they may be advertised as starters, but I've seen some sites that advertise starters and specifically state that they can only be used for a few batches), so grains are best.
If you want to PM me your address, I've got some kefir grains that I dehydrated a couple of years ago, then vacuum sealed and stuck in the freezer.
