Observing a sourdough starter or yogurt culture: a time, temperature and appearance log

Goal

Produce a record of one culture's behaviour over days or weeks in which each observation carries its time and the temperature next to the container, so that a faster or slower rise can be matched to temperature or to a changed feeding rather than remembered.

Prerequisites

One straight-sided transparent container per culture with a strip of tape marked in centimetres from the bottom; a kitchen scale; a thermometer placed beside the container, not in it, read at each observation; a phone camera. Sourdough proofing of a dough is a separate protocol; this one covers the culture in its container.

Steps

1. Header: culture name, the container and its marked scale, the scale and thermometer models with display resolution, the flour or milk type as printed on the package, and the room.
2. At each feeding or inoculation, record date, local time, the mass of each ingredient added, the mass of culture kept or discarded, the level on the tape immediately after mixing, and the ambient temperature.
3. At fixed intervals afterwards (for example every two hours while awake), record time, ambient temperature and the level on the tape, plus the highest level reached if it has already fallen (a rubber band moved to the peak helps). For yogurt, record the milk temperature at inoculation if a separate thermometer measured it, and the time at which tilting the container no longer moves the surface.
4. Describe appearance in a fixed vocabulary chosen in advance and reused every time: bubble size (none, pinhead, pea, larger), surface (flat, domed, collapsed), liquid layer (none, thin, thick), colour, and separation. Describe smell with the same discipline (mild, sour, sharp, other, with a word) and without judgement.
5. Photograph the container from a marked position with the tape in frame, at the same times as the readings; name files by date and time.
6. When anything changes outside the routine (a new bag of flour, a colder room, a missed feeding), log it as an event row.

Expected result

A table per culture in which rise height over time can be plotted for each feeding cycle with its temperature, and in which two cycles or two cultures can be compared with their conditions visible.

Limits and test basis

Proposed protocol; it records appearance, height and temperature, not composition or safety. Whether a given culture is fit to eat is outside this protocol and nothing in the log answers it. Ambient temperature beside the container is not the temperature inside it. Consumer thermometers and scales may state no accuracy, so differences smaller than the display resolution mean nothing.