I think I should have used a bigger jar!

Sourdough starters are funny. Early in their creation, they tend to explode like this. Since I didn’t mention it yet, we’re cultivating a yeast-bacteria culture suspended in a flour-water mixture. The yeast and bacteria live on the flour and in the air, and we’re feeding them with new flour and water. However, other bacteria live in the air and on the flour too! The type of bacteria that are currently present and flourishing in our starter produce a ton of CO2 when they eat – this causes the flour-water mixture to rise like we’re seeing here. Sadly, this type of culture won’t leaven a bread – and will taste terrible if you try.

So what do we do? Well…we just keep doing the same thing we’ve been doing (and we wait). The CO2 being released by our culture, combined with the water, creates carbonic acid. This lowers the pH of the contents of our jar and creates an environment that the sourdough starter that we’re growing will love! Once this happens, the bad-tasting bacteria will become much less present in the starter and the sourdough starter we want will reproduce.

To achieve this, I threw away about half my starter and added 100g of water and 60g of AP flour. I had thrown away some of the excess starter earlier in the day to keep it from overflowing from the jar. As such, I had to do a little math to know how much of the current starter to leave in the jar. For me, it was approximately 190g of ingredients inside the jar after I removed half the contents.

Most likely, the activity will continue tomorrow, though to a slightly lesser extent. In two days it will seem like the starter has died – but that means the starter we want is finally starting to grow.

Today’s tip is related to cleaning the jar when the yeast explodes with activity. I had let the sides of the jar dry out a bit too much and only using water and a paper towel wasn’t enough to clean them. I have a little pallet-knife-like spatula (see above, above a blurry picture of my finger) that I used to scrape down the sides of the walls. It will really ruin your jar if you’re not careful!