In a large bowl stir together the yeast, bread flour and salt. Fill a measuring glass with 1 1/2 cups of hot tap water. Use a thermometer to check that the water is warmed up to 125 - 130°F. Microwave the water at 20 seconds intervals if necessary. The temperature of the water must be between that temperature range. Pour in the warm water and stir to incorporate using your hands after a while if necessary.