The Master is here; He is calling you!

How long does Jesus remain present in the Holy Eucharist? Only as long as the appearances of bread and wine remain. If a sudden fire were to destroy the sacred hosts in the tabernacle, Jesus would not be burned. The appearance of bread would be changed to the appearance of ashes, and Jesus would be gone. When, after Holy Communion, our digestive processes have destroyed the appearance of bread within us, Jesus no longer is bodily present, only his grace remains.

Leo Trese, The Faith Explained, Scepter Press, pp. 363-364