This is a preferred method for many home cooks.
Bring water up to a vigorous boil and lower beans into water. Add lid. The water should begin boiling again within 1 minute (if not, there are too many beans for the amount of water.) Time for three minutes as soon as the water returns to a boil.
Immediately plunge into cold or ice water when time is up, strain to remove excess water; spread the beans out on a clean kitchen towel.
Wrap well (Ziploc-type bags are great) and freeze quickly.
Keeps well for six to 12 months in the freezer. Longer freezing is not a safety issue but may affect quality.
Note: When preparing beans, remove the stem (or both ends) chop into desired size if desired.