To blanch green beans for freezing, the typical recommended time is about 3 minutes in boiling salted water. Smaller or very slender green beans may need only 2 minutes, while larger or overgrown beans might require up to 4 minutes. After blanching, it's advised to immediately transfer the beans to an ice water bath for about 3 to 5 minutes to stop the cooking process and preserve texture and color before freezing. This method helps maintain vibrant color, crisp texture, and nutrients in the frozen green beans for up to 6 to 8 months in the freezer.