Eli5 – Why can’t you just mix a bunch of flour and water into sour dough starter to expand it?


My boyfriend and I were talking about sour dough starters and I was explaining the delicate balance of feeding it with ratios of flour and water. His question is why I couldn’t just mix a large quantity of water and flour and let the yeast just eat as it wants and then you would have a large amount of starter. And I just don’t know why. Thanks!

In: 5

Because there’s plenty of bacteria and yeast all around you. You don’t want to add so little flour and water that the starter is starving, but you don’t want to add so much that unwanted microorganisms start their own colonies and ruin your starter.

Just try making a lot of starter for a couple weeks and you’ll realize just how much it is. You probably don’t eat or bake enough to need that much, especially because it’s something you’re trying to preserve over time.

You actually could, as long as you had the right proportions it might work. But as the other poster explained you run the risk of inoculating the dough with an unwanted culture. This is mitigated by only adding a certain amount at a time you expect to be fully colonized by your culture.

But if you think about it that’s similar to what you do when making beer or wine, you’re adding only an Oz of yeast to 5 or 6 gallons of water, food, and nutrients for your yeast culture.