January 4, 2023 - 2:36am
Mould Spores on the glass container? How to remove?
I neglected my sourdough starter severely last year and by the end it was moulding in the fridge.
I tried to resurrect a frozen starter, but that one caught mould really quickly as well, as I used the same glass container, that I only cleaned with dish washing liquid and a sponge.
How do I make sure I clean the glass container of all mould spores?
Meanwhile I started a new starter in a new container, but I would like to use my Weck jars again, so please if you have some advice how to make sure all mould spores are gone, please share them!
Use bleach or boil, I think that's the best options for sterilization available at home...
Ilya is right, soak them in the sink with hot water and bleach, or just place them in a pot of water and then boil the water. I’d prefer the boiling method just so I don’t get bleach on fabrics and damage them.
Florian, the mold spores are in the air or in the flour that you are using to feed the starter, and on the baker's hands. In that sense, they are always there and even "normal", a fact of life.
Sometimes, sourdough yeast grows its colonies on the surface of the starter and walls of the jar looking like mold.
If you feed the starter frequently and wash your jar between feedings with soda and water or dishwashing liquid, they will not be visible on the surface of the starter or on the walls of the jar, on the rubber ring, etc.
Sure, you can use bleach, hydrogen peroxide, boiling water or boiling under pressure, microwaving etc. to kill the spores on the jar, but if they are in the air and in the flour, they are always reintroduced again and again and the mold will reappear during periods of long storage of the starter.
Thank you, that makes sense. Surely there must be a difference between a normal concentration of spores and a too high concentration?
I deducted that it must be the jars based on my experience. My experience at the end of 2022 was that the frozen and reviving sourdough starter would get mouldy within 36 hours in the jar, which seems like it's too fast. Previously, when I kept up a better maintenance regime (e.g. daily feedings on the counter, or weekly feedings for a fridge stored starter jar) a one-off longer duration without feedings (e.g. 36h/48h) did not produce mould at all. I just had to do a few regular feedings again with maybe a 5:5:1 ratio (flour:water:starter). Now re/ the flour itself, my new jar for my new starter also doesn't start to mould. So my hypothesis was that it must have been the jars.
Yes. I understand and I agree. I only wanted to say that soap and water, or baking soda, is enough both for the glass jars used to keep your starter in and for your hands.
Air has to be ventilated and there is nothing we can do about spores in flour except to refresh the starter often or to stir it or to sprinkle the surface with flour to stop the mold from growing.
In my starter, I once got rye flour so contaminated, that it started to grow mold after only 18hours. These are actually yeast colonies, two different species of sourdough yeast. White and pink.
Normally, my starters never get moldy at room temperature and only whole grain starters grow moldy after about a week in the fridge. White flour starters never have mold, not even after months in the fridge without refreshing them. I use the same jar over and over, washing it with dishwashing soap.
The proof that any soap and water is enough is in that experiment, where pieces of bread were touched by normal (unwashed) hands and hands washed by any regular soap. No mold grows on bread touched by the soap washed hands (no bleach, no alcohol, no boiling water, God forbid) even after one month!