I have been baking with sourdough starters for a few years but don't bake more than 1x per week. My starter normally has a grey liquid on top that I pour off and then feed the starter. Today I pulled my starter out of the fridge and it had a substantial layer of black on top. From other topics on this fourm, I saw that it was most likely mould and needed to be thrown out. Before I restart my starter, how do I avoid this forming again?
Second Random Question: Does anyone else have a starter that is/was started with scalded milk, water and flour? I have my grandmother's recipe and that is what hers is. It made for really tasty bread but then I had the black mould form after about 5 months (feeding once/week or a little less frequently).
Is the starter itself going off colour or are there black things growing on the starter?
There were black things growing on the starter. I was pretty sure it was mould and the smell of the starter had changed so I tossed it.
I googled Mold in Starters and came up with this. Your milk may be the culprit, not sure. I am under the impression that the bacteria (LAB) that is present in all sourdough starters should inhibit mold.
https://www.culturesforhealth.com/learn/sourdough/troubleshooting-sourdough-starter/
DEALING WITH MOLD
While mold on a sourdough starter is fairly rare, it does happen from time to time. The cause is usually some sort of contamination with food or soap residue, or weakened yeast due to a forgotten feeding.
If mold does appear, it may be time to discard the starter and begin again with a new starter, or it may be possible to revive the starter. Exercise good judgment. If the mold is only infecting the surface, reviving the starter may be appropriate. If mold is penetrating the entire starter below the surface, discard and obtain a new starter.
Instructions for Recovering a Moldy Sourdough Starter:
Remove the mold from the surface.
Using a clean utensil, remove a small portion of the sourdough that wasn’t near the mold. A tablespoon will suffice.
Put that tablespoon in a clean container, and feed using the ratio one part starter to one part water to a scant two parts flour. If measuring ingredients by weight, use equal parts of starter, flour, and water.
Mix, cover with a breathable lid, and proof for 12 hours.
Feed the starter again using the same ratio. Continue to feed for several days and watch carefully for any signs of mold.
If there are no signs of mold or unpleasant aroma, the starter may be used again for baking or stored in the refrigerator.
Remember that sourdough is a living thing that can be unpredictable. Thankfully it is also a fairly resilient thing that can often be brought to life even after the biggest of trials.
Dan