Sourdough seed starter maintenance
I've noticed in the forum posts there are, currently, quite a number of TFL members concerned about the maintenance and vigor of their sourdough seed starters. Being one that doesn't like debates I generally stay away from commenting on those posts. However, in this moment, having been there myself I've chosen not to comment about anyone's concern; instead the following is a description of the simple way I maintain my sourdough seed starter.
A bit of backstory: In the summer of 2011 I was forced to admit to myself that the sourdough seed starter I was using was failing. It had turned extraordinarily liquid, and not at all sticky, despite being kept at 100% hydration. I tried to save it but failed. Thinking I'd been doing all the right things, i.e. discarding approximately half my stash and replacing it with an appropriate amount of flour and water each week I was at a loss to know what to do next.
I sought help, specifically from TFL's resident microbiologist, Debra Wink. She responded almost instantly, nonetheless my seed starter had bit the dust, mostly because of my ignorance and uncertainty of what to do.
However, with Debra's nearly daily guidance I nursed a replacement starter to early maturity.
Subsequently, I had enough intelligence to ask her about maintaining my new colony of yeast and bacteria. She asked me to describe how I'd maintained my defunct starter. I described as above: throw some away, add some flour and water, stir it up and put it back into the refrigerator.
Debra didn't criticize, she simply asked "How often do you bake sourdough loaves, and do you make extra starter"? The answers were "weekly" and "yes", explaining the extra starter was insurance I'd made enough for the bake because I couldn't scrape all the starter out of the bowl. Her reply, "So you've got this perfectly good leftover fresh leaven. why don't you save it for next week's bake? "You only need to save about 20 grams to make enough for your next bake."
WOW! Why didn't I think of that!?
Over the next few months the following discipline emerged. For each weekly bake I make enough leaven to satisfy the loaves to be baked, and 60g extra. I only need 40g, but I still haven't learned how to scrape everything out of the bowl.
I take 40g of the leftover leaven and mix it with 40g of Bread Flour, and 40g of water. I cover it and let it rest for 45 mins to insure its homogeneously hydrated before chilling. "Why so much"? you might ask.
See, I'm a belt-and-suspender kind of guy. As such, I put half of the fed leftover leaven, split evenly into two half-pint Mason jars.
I so much avoid errors that I won't dispose of jar #2's backup seed starter until I know I mixed its replacement properly. The approximately 60g in each 1/2 pint jar is then returned to my refrigerator to rest safely for another week.
I don't wash the half-pint jars: never. I scrape as much of the remaining previous week's leftover seed starter I can from the jars, half fill them with hot tap water, and shake them vigorously to remove the stuff I can't scrape out. When they are clean to the eye (including their plastic lids) I fill the jar nearly full and place both the open jar and its lid in the microwave. I put a chop stick from a nearby Chinese restaurant in the jar, and nuke the set for 1 and 1/2 minutes (long enough to cause the jar's water to boil for 25 to 30 seconds). The lids also are charged with hot water. their screw-on ridges provide the same safety as the chopstick does.
Most of you reading this know the danger of super-heated water, i.e. water heated in a smooth glass jar in a microwave won't always boil when it reaches 212°F. It will continue, however to collect energy from the microwave until the superheated water is pushed into an unbalanced state. At that point the water will "explode" (instantly vaporize) and cause damage to the microwave and possibly its operator. The chop stick and the lids' ridges provide nucleation centers that trigger boiling at the proper temperature thus prevent violence.
I cool the semi-sanitized lidded jars in the refrigerator before filling them. But I'm not done with them yet.
The yeast and bacteria, although sluggish, are not dormant at normal refrigerator temperature. Over the next three days I monitor their expansion, peaking, and falling. So far it's the same every week, and another indication that all is well with my sourdough seed starter.
I've been practicing this discipline for eight years. My sourdough seed starter residents are offspring of the yeast and bacteria present eight years ago. The derived sourdough leaven I use to bake almost weekly performs exactly as it did the many weeks before.
I have no doubt that this will continue so long as I stick to this discipline.
I also have a discipline I practice developing sourdough leaven. In simple terms I build the necessary quantity for each week's bake in three progressive builds, each separated from the earlier feeding by eight hours. I believe this is a fail safe approach using seed starters that spend most of their time in a refrigerator.
Happy baking to all,