Measure out 4 ounces (112g) of all-purpose flour and 4 ounces of water into a container (see options above). It's important (and easier) to do this by weight.
Now stir the flour and water together until it is well combined and you get a thick, sticky mess. It's just going to look like a big ball of dough at this point. Cover loosely and leave on your kitchen counter.
Day 2:
Add another 4 ounces (112g) of all-purpose flour and 4 ounces of water into your container. Stir until fully incorporated into the starter. It's still just going to look like a thick dough. Cover loosely and leave on your kitchen counter
Day 3:
Same as above. Add another 4 ounces (112g) of all-purpose flour and 4 ounces of water into your container. Stir until fully incorporated into the starter. You're going to start wondering if anything is every going to happen because it's still going to just look like a thick, sticky mess. Cover loosely and leave on your kitchen counter.
Day 4:
Do you see bubbles yet? If you're lucky, magic has started to happen. But it's okay if you don't have any bubbles. Don't lose hope! Add another 4 ounces (112g) of all-purpose flour and 4 ounces of water into your container. Stir until fully incorporated into the starter. Cover loosely and leave on your kitchen counter.
Day 5:
Now you should start to see bubbles and the dough should begin to loosen up. Again, if it hasn't happened yet, don't abandon your baby! It could still happen. Add yet another 4 ounces (112g) of all-purpose flour and 4 ounces of water into your container. Stir until fully incorporated into the starter. Cover loosely and leave on your kitchen counter.
Day 6:
You really should see some bubbles and your dough should be fairly loose and thin. Add yet another 4 ounces (112g) of all-purpose flour and 4 ounces of water into your container. Stir until fully incorporated into the starter. Cover loosely and leave on your kitchen counter.
Day 7:
Congratulations! You made it! You can start to use your starter! If you aren't able to, throw about half of it out or your starter will grow too big for your container and explode down the sides! We're not going for a volcano lava science experiment here. Add yet another 4 ounces (112g) of all-purpose flour and 4 ounces of water into your container. Stir until fully incorporated into the starter. Cover loosely and leave on your kitchen counter.