The thing about starters is, they’re incredibly easy. If they weren’t, human beings would never have invented bread. The only trick is remembering to care for it. The vast majority of starter failures come from forgetting to feed one on a regular basis. If you can do that you won’t have any problems.
Begin a starter by creating a mixture of 50% flour and 50% water (by weight), say two ounces of each. Stir.
What you’ll get is something that looks like pancake batter.
All you do now is set a piece of paper towel on top of the container and let it sit for two days. After which time you may be surprised to see not much happening. Mine looked about like so:
Not much going on but a few bubbles. However the yeast were working in there, as you’ll see. The best way to tell if it’s active is to smell it. It should smell at least a little pungent…like sourdough bread.
Having gotten the beginnings of a yeast culture going, it’s time to start feeding it. This is done by “refreshing” your starter with that same 50-50 (by weight) flour-water mixture that you began with. You want to put in at least as much fresh “food” as you have starter.
So, starting with a fresh container, put in two ounces of the culture you’ve initiated (pitch the rest)…
plus 1 ounce of flour…
…and 1 ounce of water.
And stir it up. Over the next few days you’ll feed the starter once per day doing the same thing: separating out two ounces of starter and discarding the rest (lest your starter take over your house) and feeding it with two ounces of flour-water mix.
You should see a big change in the amount of activity, by which I mean a radical growth-and-contraction of the mixture each night. Here’s what mine looked like on the second day of regular feedings (day 4). It expanded about three quarters of the way up the side of the container.
That’s quite a big expansion from a scant four ounces of mix. This might be a full strength, rarin’-to-go starter of the kind you can bake with or maybe not. It’s possible that it’s a Clostridium perfringens culture which can make a person quite sick. So I check the smell — does it smell like bread? Or does it smell more like garbage (or vomit)? I’m not always sure, so I wait for a full six or seven days before I use it, just to be certain I’ve cleared out all the suckers (i.e. potentially harmful bacteria).
This is what the starter typically looks like in the morning once it’s exhausted its food supply: collapsed.
What’s happening here is that the yeast have reached their peak population and lacking any more fuel to keep growing are lapsing into a kind of semi-dormancy. A starter that looks like this should still, however, be considered a full-strength leavener. It will remain so, refrigerated, for up to three days.
Having created a starter, you can simply keep it out all the time, refreshing it nightly. That, however, can get tiresome unless you’re using one several times each week. The way to store it is to give it a fresh infusion of food, let it sit for half an hour or so, then put it in the fridge. Fed a minimum of once a week, it’ll stay active indefinitely. I generally keep the same eight- or twellve-ounce quantity in the fridge, since it doesn’t take much to feed and I know I can build it up to whatever I need in one or two days’ time.
What to do if you have more starter than you need? Make sourdough pancakes, sourdough fritters or sourdough onions rings. There are recipes for all of them on the site under Bread, Pastry and Totally Not Pastry respectively.