The Forty-Second Bloom
Why we wait before the second pour, and what the first forty seconds tell you about how fresh your coffee is.
Fresh coffee holds carbon dioxide from the roast. Pour a little water over the grounds, twice their weight, and you will watch it leave: the bed swells, bubbles, then settles. That is the bloom.
Give it forty seconds. Water cannot extract evenly while gas is pushing it away, so the wait is doing real work. A lively bloom means the coffee was roasted recently. A flat one means it is time to order again.