A friend recently tried to start a wild sourdough starter. It sounds like he was off to a great start, then the report was that it started to get liquidy, then look funny, then STINK. Poor sourdough. My diagnosis was that it was so vigorous that it needed to eat more than the once-per-day that the instructions he was following dictated, and it succumbed to some “bad” microbes.
Sourdough starter needs to be kept in a “fed” state or the “good” bacteria and yeasts that define a sourdough culture cannot keep invaders at bay and the mix will turn bad. An active culture kept at room temp needs to be fed once per day, but sometimes it can be more often depending on some variables. One kept most of the time in the ‘fridge can be fed just once per week; The cooler temps slow the metabolism of the bacteria and yeasts and they will work through nutrients more slowly. I’ll add that the ‘discard’ process is important — always discard at least half of the starter and replace with the same amount of fresh flour/water.
I will soon make a post that details how TO care for and bake with a sourdough starter. This is what happens when a starter starves. Sorry to the starter I sacrificed for this experiment — science thanks you!
Day 1 — 11pm. This is some sourdough starter that I poured off my main batch, which was then fed. It is slowing in activity, but still has a bit of body and a few bubbles.
Day 1 — 11pm, top view.
Day 2 — 10am. Starter is starting to get thinner. No new bubbles have formed, a sign the mix is lacking in nutrients for the “good” bacteria and yeast that define a healthy sourdough starter.
Day 2 — 1pm. “Hooch” or liquid is starting to form on the surface of the starter. This is a telltale sign of starter that is “hungry”. It’s natural for some to form between feedings, especially if you’re keeping it in the ‘fridge. Starter is still viable at this point, but losing potency. A couple feedings will be required to bring it up to the strength to raise bread dough. You can mix the hooch back in to the starter when feeding or pour it off.
Day 2 — 6pm. More hooch is coming to the surface.
Day 2 — 11pm. Even more hooch. No bubbles. This is not a happy starter.
Day 2/3 — 3am. I’m up late. I’m tired and the starter’s exhausted!
Day 2/3 3am — side view. Note the clear presence of the liquid on top of the starter.
Day 3 — 2pm. More of the same, but getting more pronounced. It still wouldn’t be too late to revive this. A couple “power feedings” every 6-12 hours and it would probably bounce back fine.
Day 3 — 2pm side view. Note that things are settling and layer of hooch is more defined.
Day 4 — 2pm. WHOA! What’s this? It’s neat looking, but it smells like gross sweaty feet. This is likely kahm yeast. This is an opportunistic yeast that is taking advantage of the drop in pH in the spent starter. Kahm yeast is not harmful but it does not taste good and it’s virtually impossible to actually remove once it sets up camp. There is a chance that at this point the culture could be saved with some power feedings, but it’s pretty far gone. The presence of this yeast is a sign that the culture is also open to mold.
Day 4 — 2pm, side view.
Day 5 — 5pm. The yeast layer is taking on a pink hue with is NOT a good color to see in ferments. I’m not sure if it’s the kahm yeast itself or a sign of another microbial invader, but at this point I would call this un-salvageable. The smell is increasing in strength and unpleasantness.
Day 5 — 5pm, side view.
Day 6 — 2pm. Kahm yeast is in full force. It looks really cool but smells awful. From looks the kahm layer is just on the surface of the hooch, but with things like yeast and bacteria, once they’re on the surface they’re likely throughout what they’re growing on too. The color has deepened. RIP sourdough starter. I’m calling it quits on the experiment. Likely within days or maybe up to weeks mold would move in and this would be a disgusting soup of things you do NOT want to eat!
Day 6 — 2pm, side view
Back to day 1. This is a side-by-side comparison of the experimental starter and my main starter, which I had just fed. If you look closely you can see the line the fed starter comes to in the big jar — about half-way.
About 12 hours after the last photo. You can see that the small jar of our experimental starter looks pretty much the same, whereas the fed starter has doubled in size and fills the jar — what a healthy starter should do after a feeding.