PDA

View Full Version : The subtle art of freezing food so it will last















FenceFurniture
21st March 2020, 07:29 PM
Don't panic buy! Panic cook and panic freeze instead! :2tsup:

I have been cooking in bulk and freezing food for well over a decade, and for a few reasons, including

Meal prep is substantially reduced in time and labour.
Seasonal produce can be taken full advantage of.
I can prepare bulk ingredients (garlic, ginger, lime juice etc etc), and then just use a cube or two at a time. This is REALLY useful.


I have two upright freezers. One is a generic frosty jobbie which was cheap ($200?) in about 2008, and the other is a Haier Frost Free (https://www.haier.com.au/products/freezers/?productuid=6E004AED-A815-72BC-2542D2F6C2FC976A) which I purchased in about 2016 for $850. The Haier is a beauty, although it makes some weird cyclonic noises, but the frosty jobbie is a bit of a PITA. I usually try to store things in that that I don't reference very often which minimises opening and closing it, because that is what leads to it frosting up.

Now to freeze food properly you really need some kind of vacuum packing machine. You can get cheapie "channel" bag jobbies (https://pacfood.com.au/wp-content/uploads/MCB-4-3.jpg)from a variety of places, and I suppose, but don't know, that they work reasonably well. Hopefully that link will lead you to a pic where you can see the checkered pattern of channels on the bag. I don't know quite how they work, but the bags are fairly expensive.

My Vacpack machine is a chamber jobbie, an Italian made Orved VM-12 (https://www.sydneycommercialkitchens.com.au/brands/orved/orved-commercial-vacuum-sealers-vm12) and the whole chamber will go down to the vacuum that I set. These machines are significantly more expensive, but the bags for these chamber type machines are less expensive, as they are just a welded (3 sides) bag. There are various sizes. Food that is packed in this machine will last for years at -18°C or less. Two years ago I made 28 litres of Coriander Pesto, and I'm now down to my last two litres. I have used this machine to take out bubbles from epoxy resin before application too.

Last weekend I made some Gozlemes with Silverbeet that I grew, steamed, froze and vac packed 3 years ago. It was perfect, but frozen food often sheds some water when it's defrosted.

Always best to wait until food cools before vac packing, especially liquids. Water boils at around 20°C in a vacuum, and so can very easily boil over in the chamber which is a right PITA!

More in the next post.

FenceFurniture
21st March 2020, 07:49 PM
Why snap freezing works better.

The story goes that the guy who invented snap freezing was fishing through a hole in the ice and pulled up a fish, dropped it beside him, and carried on fishing. This was somewhere in North America at an appallingly low temperature. The fish was frozen solid within a few minutes, and he noticed that it seemed to be as good as new when he defrosted it and cooked it.

The reason for that is that the quicker something freezes the less the ice crystals grow and it means that they don't penetrate the cell walls of the food as badly. When the cell walls are ruptured and then defrosted the cells can shed out some water content. It is also for this reason that you will see more blood from defrosted red meats than you do from meat just stored in the fridge.

Unfortunately, snap freezing requires specialised and very expensive freezing equipment.

Freezing works much better with cooked food, but it is pretty much a waste of time trying to cook/freeze/reheat red meat in the form of steaks, unless you like them pretty well done. I've never really achieved a satisfactory result. OTOH, chicken works brilliantly - you'd never know it was cooked over a year ago.



So the secret to good freezing is to make sure that the food is properly sealed off from the atmosphere, otherwise you get freezer burn after a few weeks, particularly in a frost free freezer. They reduce moisture content dramatically, which is why they are what they are. Freezer burn in frosty freezer (like my cheap jobbie) takes longer to happen and is not as severe.

If you don't have a vac packer then using two zip lock bags can work reasonably well. It was how I started out but I can't remember how long food lasted - maybe three months? Certainly I would think that a cheap channel bag vac pack would do a better job than a couple of zip lock bags.

FenceFurniture
21st March 2020, 08:13 PM
Revisiting this point in more detail:
I have been cooking in bulk and freezing food for well over a decade, and for a few reasons, including


Meal prep is substantially reduced in time and labour.
Seasonal produce can be taken full advantage of.
I can prepare bulk ingredients (garlic, ginger, lime juice etc etc), and then just use a cube or two at a time. This is REALLY useful.



Starting with the last point first, bulk prep of ingredients.
Cutting up garlic for a meal to cook absolutely irritates the bejaysus outta me. It's fiddly, sticky, smelly. One of the several silicon moulds that I have is a tray of 18 cubes that are 20mm dimension, which is around 12-15 grams depending on how tightly I pack it down. So I put 5 frozen cubes (in a 5x1 line) in a super-flimsy sandwich bag, and make 5 of those, and then put the 5 lines into a proper vac pack bag, and do the vac pack procedure. I keep one line out (still in the flimsy bag) in a hard plastic lidded container (in the freezer) and use a cube at a time - they can be cut in half or less if necessary. As I finish a line I cut open the vac pack store, take out another line and re-vac the store. The line goes into the hard plastic box, so I have Garlic, Ginger, Galangal and lime Juice in that hard box, all super available. You would never know the difference between freshly cut and these cubes....

The reason for the flimsy bags is to stop the lines adhering to each other so they can be easily removed from the vac pack - they are under huge pressure in there so are forced together and will stick like the proverbial.

So right now, at 8:12pm, having written about food for the last 45 minutes...I'm bloody starving, and it's Pizza and Gozleme night (defrosted the Gozleme earlier), so pics will have to wait until tomorrow. :U

Chris Parks
21st March 2020, 10:30 PM
Do you need a freezer in Katoomba? We have three freezers and they are never empty.

FenceFurniture
21st March 2020, 10:41 PM
We have three freezers and they are never empty.No, never empty - at least filled with air.

Re needing a freezer up here....some years ago we were going to someone's place for dinner in May or thereabouts. Lola said something about taking the wine (white) in a cooler bag with an ice brick. I said "leave out on the porch for a while".