How old is Larry? That's the wrong question.

Everything else in this kitchen sits quietly in a cupboard. Flour keeps for months. Sugar keeps indefinitely. Cardamom fades but does not object.

The starter is the exception. It is a population of living organisms in a jar, and if I ignore it for long enough it stops being useful and eventually stops being alive. Nothing else here can be killed by inattention.

Mine came to me in 2023 from an Irish friend who had got into sourdough during the pandemic. I know how long Larry has been with me, but not how old he actually is.

What is in the jar

Two kinds of things, working together.

Wild yeasts, which eat sugars from the flour and give off carbon dioxide. That gas is what lifts a loaf.

And lactic acid bacteria, which are the more interesting half. They produce lactic and acetic acid, which is where the sour comes from, and which drop the pH of the dough far enough that most other microbes cannot establish themselves. A mature starter is not a fragile thing that might get contaminated. It is an environment so acidic that very little else can move in.

The two are not competitors. The bacteria produce conditions the yeasts tolerate better than their rivals do, and the whole arrangement is stable enough to be kept going more or less indefinitely by anyone who remembers to feed it.

What feeding does

Discarding most of the starter and adding fresh flour and water sounds wasteful and looks like a ritual. It is neither.

A population that is not fed exhausts its food, sits in its own increasingly acidic waste, and slows down. Feeding resets both: fresh sugars, and dilution of the acid back to a level where the yeasts are vigorous rather than merely surviving. The discard is not tribute. It is how you keep the amount manageable, because a starter that is fed without being reduced doubles in volume every time.

A starter that has been left too long is usually not dead. It is exhausted. Two or three feeds a day apart will normally bring it back, and the way you know it has come back is that it rises predictably and on a schedule rather than sluggishly and whenever it likes.

Why it matters here

Because it is what decides when a bake can happen.

Commercial yeast is a product with a specified performance. You add a measured amount and it does a measured thing. A starter is a population whose activity depends on how recently it was fed, how warm it has been, and what it has been fed on. Those are not settings. They are conditions, and they have to be managed forwards rather than corrected afterwards.

Which means the state of one jar decides what is possible on a given day. A naturally leavened bake is not something that can simply be moved around a diary.

Keeping one

If you want to keep a starter and you do not bake often, keep it in the fridge and feed it once a week. Bring it out and feed it twice at room temperature before you intend to use it. That is the whole maintenance schedule.

Use flour with something in it, a proportion of wholemeal or rye rather than white alone, because a starter fed exclusively on white flour is a starter on a restricted diet.

And do not put too much weight on how old it is. A starter is not a vintage. Once it is established, the one begun last month behaves like the one that has been passed along for years, because what you are keeping is not a specific ancient organism but a set of conditions that a succession of organisms find agreeable.

Which is the argument for thinking of a starter as weather rather than as an individual. Mine is called Larry anyway.