Wash the spinach thoroughly in cold water
Remove any damaged or yellow leaves
Trim off tough stems if desired
Dry the spinach completely
Blanch the spinach in boiling water for 30 to 60 seconds
Transfer immediately to ice water to stop cooking
Drain well and squeeze out excess moisture
Portion the spinach into freezer-safe bags or containers
Remove as much air as possible
Label with the date
Freeze flat for easier storage
Use within 10 to 12 months