How to interpret what you see
| Test result | What it can tell you | What to check before mixing |
|---|---|---|
| Floats | The spoonful held enough gas to stay on the surface. | Check how far the jar has risen and whether it has reached the recipe’s ripe stage. |
| Sinks | The sample did not stay afloat under those conditions. | Review the flour, hydration, handling and the actual rise in the jar. |
| Breaks apart or some pieces float | The sampling conditions made the result difficult to interpret. | Use the jar observations and skip another test unless you are comparing handling. |
King Arthur’s demonstration found that a sample can float before the starter is ready. The Sourdough School also notes that active rye or whole-grain starters can sink. Taken together, those are good reasons to treat the result as a clue about one sample. [1] [2]
A simple side-by-side demonstration
On a feed that has reached its usual high point, note the time, flour, ratio and height against the starting mark. Lift a small, gently scooped sample into one glass of water. Take another portion of the same starter, stir it separately and put a similar-sized sample into a second glass. Use the same water temperature and look at both under the same conditions.
Record “floated”, “sank” or “broke apart” for each. If the results differ, the samples came from the same jar at the same time, so handling is a plausible explanation. This is a demonstration you can try. Record whichever result you actually see. Dispose of the samples after checking and keep raw starter out of taste tests. [4]
A more useful check before baking
Mark the level after feeding. See whether the starter rises reliably across comparable feeds, whether bubbles are visible throughout, and whether it meets the ripeness cues in your recipe. Compare a rye starter with its own usual behaviour rather than using a white-flour jar as the baseline. A single early burst from a new culture is weaker evidence than a repeatable pattern. If the top has already fallen, note the high-water mark on the glass and check earlier after the next comparable feed. [5] [2]
Crispy Crust’s planned starter log would keep the feeding details and height observations together. That would make it easier to compare a doubtful float result with what the same jar did the last time it raised a loaf.