Though I've already shared how I go about freezing blueberries, my method for freezing raspberries and strawberries is somewhat different, because they can tend to be juicier fruits that stick together in the bag once frozen.
It's no fun to be banging a bag of frozen, stuck-together berries on the counter in frustration each morning (been there, done that). I've learned to do freeze my raspberries in a way that isn't too tedious, but keeps them frustration-free for easy use!
I wash my raspberries off using my double sink and two strainers, just as I showed in my blueberry tutorial.
Here's where the difference begins... once the raspberries have drained in the sink for a moment or two, I begin to spread them out on parchment-paper covered cookies sheets and various sized baking trays.
I use whatever trays and containers I have available, because I want to be able to freeze as many as possible at one time. The parchment paper (or you could use wax paper as well) isn't 100% necessary, but it really does help to make it easier to get the berries off of the trays.
Green tip: Remember to use as little paper as you can get away with, and keep reusing it over and over again until you can't use it anymore!
I try to keep them only one layer of raspberries deep. Sometimes a few end up on top of the others which is fine, but if I start double layering the whole thing, I begin to run into clumping difficulties.
Once these trays are full of washed berries, I take them all to my deep freeze. I basically cram them into every nook and cranny (putting some on top of each other, depending on the type of tray/container they're in, if they won't squish each other).
I leave them in my freezer for about 1-3 hours, just until they are starting to freeze but are not fully frozen and can still be easily taken off of the paper/trays and the individual raspberries can easily separate from one another.
At this point, I break everything up and dump it into my large Ziploc freezer bags. Each bag will take about 4 lbs or so, on average.
Then I put my full bags down in the deep freeze and I usually just forget about them and consider them done. If I happen to go down to the freeze later that day, I will take them out and give them a light "drop" on the floor to ensure that the berries stay separate. Even if I don't remember to do that, usually a quick drop on the counter when I start using that bag will break them apart enough because of the pre-freezing.
Yes, it's slightly more work, but this means that we can easily grab as many or as few berries as we need at any given time. For smoothie addicts like us, this just makes life a whole lot sweeter and easier!