Hot water extraction is widely used in the food industry, but imprudent process causes considerable loss in bioactive compounds. The effects of the extraction temperature (60–90 °C) and time (5–180 min) on the total soluble matter (TSM), antioxidant activity, and ginsenoside content of hot water extracts were studied. Also, we evaluated the stability of the extracts based on ginsenoside degradation, loss of antioxidant activity by overheating treatments. The temperature dependent TSM, reached a maximum within 60 min and subsequently plateaued at all temperatures. Antioxidant activities peaked at 60 min, then remained steady or declined at all temperatures. Individual ginsenoside contents were dependent on temperature and time with different patterns. After infusing the extracts at 90 °C for 60 min followed by separation, an overheating treatment resulted in ginsenoside degradation, altered color value and browning index, and decreased antioxidant activity. However, no changes were detected in the extract held at room temperature. The extraction at 90 °C for 60min showed the highest antioxidant activities and ginsenoside contents, however, further heat treatment caused decrease in antioxidant activities and ginsenoside contents.