A starter in a warm kitchen

Heat is an ingredient whether you write it down or not. Wild yeast and lactic bacteria both hurry as the jar warms, and they do not hurry by the same amount. In a kitchen that sits at 30 °C, a feeding that took six hours in a mild room may crest in three, and the balance tips toward acid. The loaf that follows tastes sharper and can go slack if you wait for the clock instead of the jar.

The practical fixes are small. Feed a larger ratio, so there is more fresh flour for the same spoon of seed: 10 g of starter with 50 g of flour and 50 g of water takes longer to peak than equal weights. Use cooler water, straight from the tap if the tap is truly cool, so the mixture starts below room temperature. And build the levain later in the morning if you know the day will be hot. The note in the boule says the same thing. Watch the jar, not the clock.

A warm, humid kitchen also wets the flour in the sack. Dough then needs less water than a formula written in a dry season. Ten grams less water in a 500 g flour formula is 2% of hydration. That is enough to change how the dough feels in the hands, and not enough to ruin it if you notice while you mix.

If you cannot stand over the jar, the fridge is a pause button, not a failure. A levain that has risen halfway can go into the cold and finish slowly. Bring it out, let the chill leave, and use it when it looks domed. Ripe is a shape and a smell. It is not a time of day.

None of this requires a proofing box. A starter that lives in a hot climate just wants a slightly stiffer feeding and a baker who is willing to move the schedule. The culture itself is the same one from the first week.