Sourdough Starter Manager
Log each feed, watch your starter rise in a 3D jar and record when it peaks. After two feeds it learns your own starter’s timing, so you know when it will be ready.
- See the rise against the clock
- Learns your starter’s peak time
- Free, no account needed
Start with the discard decision
If you find fuzzy growth or unexplained pink or orange streaks in a starter, stop using it and discard the entire contents. Do not take a clean-looking spoonful from underneath, feed it repeatedly to “clean” it, or bake with it. The saved portion is not an independently uncontaminated backup.
Keep the affected jar away from other cultures while handling it. Avoid sniffing visible mold closely or tasting raw starter to investigate. Seal the unwanted contents for disposal, then wash the jar, lid and utensils thoroughly before reuse. If a container is damaged, has a difficult-to-clean seal or cannot be cleaned properly, replace it.
The relevant distinction is hungry versus contaminated, not whether the starter is old enough to be valuable. A healthy starter can be rebuilt; a contaminated one is not worth preserving.
Compare liquid, bubbles and surface growth
| What you observe | What it may mean | Next action |
|---|---|---|
| Clear, grey or brown liquid above otherwise normal starter | Hooch or separation | Inspect the whole jar; if no contamination signs, follow normal feeding guidance |
| A ring at yesterday’s high-water mark | Dried starter left after a rise | Clean the jar and reduce residue during the next healthy feed |
| Gas bubbles distributed through the mixture | Fermentation activity | Judge rise and repeatability as well as bubbles |
| Fuzzy or coloured patches on the surface or jar residue | Suspected mold | Discard the entire starter |
| Pink or orange tint or streaks | Unwanted contamination | Discard and restart |
| An unfamiliar flat, wrinkled or chalky film | Uncertain surface growth | Do not assume it is harmless “kahm”; restart if identity is uncertain |
This table is a decision aid, not an identification laboratory. Flour particles, lighting and dried residue can look confusing in a photograph. The absence of an obvious colour is not proof that a new surface growth is safe. Never use a generated picture as a diagnostic reference.
Why hooch is a different problem
A neglected but otherwise healthy starter can separate and develop liquid. That alone does not mean the culture has mold. Record how long it has been unfed, its storage temperature and whether the liquid is on top or incorporated. Then inspect the surface, jar sides and lid before refreshing it.
If you see only normal separation, use the hooch guide to choose whether to pour off or stir in the liquid and adjust feeding. A hungry starter needs an improved routine; it does not need an improvised antifungal treatment.
Do not let a familiar explanation overrule a new warning sign. A jar can have hooch and a contaminated dry rim. If either location has suspicious growth, discard it.
Related calculator
Sourdough Starter Feeding Calculator
Exact starter, flour, water, and discard for 1:1:1, 1:5:5, or any custom feeding ratio, with a ratio chart and peak times.
Restart without carrying contamination forward
Use a separately stored healthy starter, fully dried backup, or a fresh culture. A backup means material removed before the problem and kept separately, not discard from the affected jar after you noticed the change.
Clean the preparation area and use fresh flour and clean water. Keep the new jar labelled with the feeding date and ratio. If recurring growth appears, check flour storage, damp utensils, lid seals and residue above the mixture. Do not store flour beside a visibly affected ferment.
For a new culture, follow the starter creation guide. For an intact dried backup, follow the rehydration guide. Do not treat the first burst of bubbles in a new mixture as a guarantee that it can leaven bread.
Free Sourdough Baking Playbook (printable PDF)
A printable PDF companion for the sourdough calculators and guides.
Make the routine easier to keep clean
Keep a small working culture in a jar with enough space for its rise. Scrape down the walls after feeding and change to a clean jar when dried residue builds up. Use a suitable cover that protects against debris without creating a pressure hazard during active fermentation.
Feed according to temperature and use. A warm kitchen can run through a small feed rapidly, so choose a larger feed or a cooler location rather than letting the same ratio sit for days. Refrigerate a mature starter when you are not baking frequently, and keep a dry backup away from the working jar.
Write a short log: flour, feed ratio, temperature, rise time and unusual changes. If the problem returns, that record is more useful than changing all the flour, water and storage conditions at once. See starter storage for a manageable absence plan.
Reference guidance and image limits
King Arthur Baking’s starter troubleshooting guidance distinguishes hunger-related liquid from mold and pink/orange contamination. USDA FSIS guidance on mold explains why visible growth is not always the full extent of contamination in soft or porous foods.
We have not supplied diagnostic photographs here. Use the observable discard criteria above; a photograph alone cannot certify safety. Reference-image additions must be accurately identified and used with permission.
