You can air dry starter and reconstitute in about three days. Put it in a coffee grinder and add equal parts flour, then add water until it’s the consistency you like.I used to make it a lot, but I never heard of using citric acid. I am literally addicted to homemade bread, so I hardly ever make it & when I do, I send most of it home with guests. I love bread, but I love not being fat a whole lot more.I used to maintain a starter that was really vigorous, and the bread was amazing. Now if I want to make it I just add kefir & proof the bread at least overnight. I miss that strong umami flavor, but maintaining a starter just to use it a couple times a year is too much trouble.