If your culture isn't showing signs of life after 3 days, go ahead and start feeding. If, after a few more days, nothing happens, start over and place the culture in a different part of your home. Why the long wait? Even at refrigerator temperatures the starter will continue to do its thing, consuming starches and creating complex (and tasty) chemical waste. Without this time the crackers would lack in both flavor and flakey texture. So…your patience will be rewarded.