Why isn't my sourdough starter active yet after 3 weeks?
Three weeks ago, I started a sourdough starter using Chad Robertson's Tartine Bread book, and it is not active yet. There are tiny bubbles, the smell is right, it tastes sour, but it is just not doubling rapidly after a feeding. I feed it twice a day, 50 g flour and 50 g water, and keep it in my kitchen (averages 63 degrees). Should I keep feeding it or start over?