HOW TO TAKE CARE OF YOUR SOURDOUGH STARTER
After you take your starter home from the bakery:
Take your starter and scrape it into a larger container (mason jar works great). It is hungry, so you can feed it right away:
Since you have about 50g of starter to begin with, feed it by adding 5 times that amount of flour (250g) and 5 times that amount of water (250g) to the mason jar and mix well with a spoon until most of the lumps are gone. It should look like a thick pancake batter.
If you don’t plan on baking with it in the next few days, you can then put the jar (with lid) in the fridge.
Starter in the fridge can be feed weekly, give or take.
To feed: Dump out most of the starter into the trash (or you can find some recipes online to use unfed starter), and whatever sticks to the inside of your jar is plenty to keep, so you’ll need to feed it by adding some flour and water, just like before, and mixing it up well. Back in the fridge it goes until you plan on baking.
When you plan on using it to bake, you’ll need to wake it up for a day or two first. You do that by taking it out of the fridge and leaving it on the counter at room temp, and feeding it just like before (dump most, add flour and water, mix well). Feed it one or two times a day for 2 days (keeping it on the counter between feeds this time) until you need to bake with it.
Add the starter to your sourdough recipe about 6 hours after you’ve fed it, so it should have about doubled in size in your jar. Measure out what you need for your recipe, then feed what remaining starter you have in your jar just like before, by dumping out what you don’t need, and feeding what’s stuck in the jar with flour and water.