Sourdough can be simple.

Normally, it takes 10 to 14 days to get your starter going, but it can be kick-started with 1% dry yeast, and you can have it the next day. I saw some jars with poolish (you can find it under many names) for €9,90, and I laughed a little. I'm a bit sick of this "it's so complicated" attitude which exists only to make people pay a lot of money for next to nothing.

Not everyone has a lot of free time so here's the easy way.

We'll start with 100 grams of water, 100 grams of white flour, and 2 grams of dry yeast (or 1/3 of a 7g satchel, in case your scale isn't in its best shape, or 1/3 of a 25g pack of regular yeast). You can go with a larger quantity, but you need to keep the 1% proportion. [2g yeast for 200g (100g flour 100g water)]

Mix them together in a casserole, or anything with a lid, and put it overnight in the fridge. You can use it even after a few days, no worries, so it won't get bad for up to 2 weeks.

Tomorrow, or the day after tomorrow, we'll use 100 grams of this polish to make bread, and we'll put back 50g of water with 50g of flour (no more yeast from now on), and you can use this starter for years.

Stay tuned! (I would have posted it at a later date, but here we use PoW.)