My spinach is ready so I cut a small amount to show how to blanch and freeze it. It's a lot more efficient to do this in larger batches, but I cut just a small amount to show how you do this. It's very easy, and a simple text explanation would probably suffice, but I know that pictures and step-by-step directions are helpful.
After cutting you want to wash the spinach well. Spinach has all kinds of nooks and crannies for dirt to hide. After washing your sink well, place the spinach in the sink and move it around in cold water.
Start a pot of boiling water and after the water starts to boil, pour the spinach into the pot
It will shrink down to almost nothing. Boil it for one minute, then remove it from the pot and dump into cold water to stop the cooking process.
Now you want to drain it, and drain it WELL. First I drained it in a colander
I even went as far as placing it on a CLEAN towel and squeezing more water out of it.
Now all you have to do is place it in a freezer bag, or freezer container of some sort. I like to use my FoodSaver vacuum sealer
ALWAYS label your freezer bags/containers. The few times that I haven't, I have regretted it. Six months later you don't want to pull something out of the freezer and wonder "What the heck is this, and how old is it?"
So, as you can see, blanching is easy. The only thing that varies is the amount of time you hold it in the boiling water. Things like broccoli/cauliflower take about 3 minutes, but something thin like spinach only takes a minute.
Blanching slows or stops the action of enzymes in the plants. While the vegetables are living, enzymes cause vegetables to grow. If vegetables are not blanched, the enzymes continue to be active during storage causing off-colors, off-flavors and toughening of the vegetable.
I grew a lot more spinach this year than I usually do, just to try freezing as much as I could. Spinach doesn't grow well in hot weather and normally I get to eat it only for a few weeks. I hope to extend the spinach-eating this year!