Keep your culture in log every day.
Do not pay attention to any external clues until your starter is established. Pretend you’re Helen Keller. Ignore all visual, tactile, or olfactory input until your starter is established. (“It smells like acetone.” or “It’s not doubling.”)
A culture can change completely in only 3 – 5 generations under optimal conditions.
If you use Saccharomyces cerevisae commonly, there’s a good chance (more than 50-50%) it will end up as a permanent, stable cast-member in your starter’s microflora, usually as a mutant strain that, as a result of random genetic mutation, has decided to go native.
Understanding why a specific organism evolved the way it did will also allow the baker to reverse-engineer optimal parameters.
Grain-based microflora will always win out over every other organism, except one: Lb sanfranciscensis.
Never refrigerate or freeze your starter. Ever. Throw it out. Start a new one. How? Easy. Just do this.
Lb sanfranciscensis does not have a latency period (i.e., it does not take two weeks to get a well-established culture up and running). Don't believe me? Read here.
A “mature” or “ripe” starter is one that has a pH of at least 4.0.
100% flour is the same as saying maximum microflora population.
For an Lb SF-based culture, only feed your starter wheat or rye, preferably as whole a grain as you can. Stone-ground’s even better.
Weigh. The margins of error are too small, and you may very well unintentionally change the entire nature of your starter if you do not.
Measure temperature. See above.
Mix at the same time every day, preferably at some point during day time. It is best to find a point that best meets your routine.
For the most flavour, maintain a starter with a hydration within the range of 50 – 75%.
The most effective way to increase total acetic-acid content is to oxygenate your starter. I simply tear mine apart at regular intervals throughout the day and stick it back together.
Do not stress your culture out: Adapt it. How? More on this later.