Test jam for consistency. For this step I keep a tablespoon in a glass of ice water near the stove. spoon out about a half tablespoon of the jam out of the boiling pot, and let it cool on the spoon. Then turn the spoon up on edge. If the jam either sticks to the spoon or falls off in a lump (as you would expect jam to do!), then it's ready. If it runs off like liquid, keep boiling another 1-2 mins and try again.