Friday, December 05, 2008

Response to Jordan

So Jordan asked me about freezing stuff. I'm not exactly an expert on this, but I'll share what I can.

Obviously, we freeze things for one of three reasons:

1.- They're supposed to be frozen (ice cream, ice, Ted Williams)
2.- We want them to last and not spoil (meat, leftovers, Walt Disney)
3.- It's an interesting experiement on the effects of cold on our enemies

But the questions was - how long?

My answer? Depends.

When you freeze something to keep it from spoiling, you're doing so to prevent bacteria growth. Most food bacteria survive freezer temperatures, but the growth comes to a stop since you're freezing them along with the food. So, as long as things are put in fresh (if raw) or soon after they've been cooked, the question of spoilage is fairly moot.

So the question becomes - is it still good? Well, it's generally edible, but sometimes it's not very tasty. Freezer burn occurs because the water in the cells eventually sublimates (think shrinking ice cubes), and the food becomes dried and shrivelled. There isn't really a hard-and-fast rule on how long this takes, as the type of freezer, packaging, environment, type of food, and other factors can contribute.

For instance - a manual defrost freezer maintains a more constant temperature than an auto-defrost one, so will lessen freezer burn. Think of winter - at -1 (30F), the ground is covered in ice At +1 (34), it's all slush. If your freezer fluctutes by +/- 1 degree from zero, the same thing can happen at the surface of your frozen food. A tightly or vacuum-wrapped piece of food will also stave off burn longer because it maintains humidity better within the packaging, and the sublimiation takes longer. but neither of these measures will keep freezer burn away forever.

With something like ice cream, it's a similar story, but slightly different. Every time you open the freezer door, or take out that tub of Cherry Garcia, you're raising the temperature. The ice cream melts a bit, some water evaporates, and then you return it to freezing. You get ice crystals forming on top. Sometimes known as the "protective ice shield". An Alton Brown tip for homemade ice cream is to portion it out into smaller containers, so you're not exposing the whole batch to room temperatures every time you serve. As well, there's a reason commercial ice cream has a plastic sheet on top of it. Take some plastic wrap and lay it on the top of the ice cream (not the container, the ice cream itself) when you freeze it.

So, how long can it all last? You're usually pretty good for a few months with most things before burn starts to kick in. Things like soup and other high water-content items will probably last longer since they're mostly liquid anyway. I've got meat that's lasted over a year in vacuum-packed plastic, while the same meat has burnt in a matter of weeks when the seal is broken. Your best bet is to store everything in clear containers or plastic wrap instead of foil, so you can actually SEE what it looks like.

But even if your food succumbs to some burn, it's not the end of the world. Freezer burn tends to be unevenly distributed, so as long as the whole thing isn't gone, you can just cut out the burnt parts once thawed and cook the rest. If that would decimate the food, then be creative. Steak or chicken becomes a stir fry or fajitas. Strawberries become jam or topping or pie. I recently did a beer can chicken with a roaster that had been in my freezer for over a year. The chicken looked like crap when it thawed, but after some liberal seasoning and roasting with beer infusing it, it turned out really well.

Vegetables will shrivel up and dry out after particularly long periods in the freezer. Most store-bought frozen veggies are flash-frozen to retain water and flavour and such, but your freezer isn't THAT cold. Some can be revived by soaking in water first, but most end up tasting "frozen" if they've been in there too long.

I'm sure some food safety nut will disagree, but I've never had a problem with anything coming out of my freezer health-wise. As long as it goes in before it starts to turn bad, it should still be perfectly healthy to eat when it comes out and is cooked properly.

There are something that shouldn't be frozen though - whole citrus fruit comes to mind. Water expands before it freezes, so anything that has contained water (ie.- an orange, think of each of those juice-filled cells) will likely "explode" and be useless when thawed. Things with a high alcohol or sugar content also won't freeze well either (think sticky popsicles if they've been in there too long). High-fat liquids (like milk or cream) will separate when frozen, and thaw strangely.

Also, there's a reason that your folks cooked every piece of meat in the freezer that time you forgot to close the door and nobody noticed until Tuesday. Once you thaw frozen food, bacteria growth begins anew. In many cases, even faster than before. Refreezing just isn't an option with things that have completely thawed (I'd argue that it's probably okay if it's only thawed a little, but is still generally frozen solid). So if you take out that roast, make sure you'll use it.

Make sure you freezer is cold enough. It should be set around the midway point of the dial (usually, freezers differ, read your manual), and be around 0 degrees C (32F). Any warmer and you aren't freezing anything, too much colder and you'll see lots of ice crystals and freezer burn.

As for thawing - I'm probably Alton Brown's worst nightmare when it comes to thawing. I often don't decide what I'm eating until I'm on my way home, if not later. If that something is chicken or steak, it usually involves me pulling a piece of meat out of the freezer. A solid steak can take all day to thaw on the counter, and a chicken breast all day in the fridge. A turkey? I buy those fresh.

Now, the PROPER way to thaw food is to put it in on a plate in the fridge. This allows for a slow thaw in a cold environment, which keeps bacteria growth to a minimum. I only use this method when I'm thawing a roast, since it's hard to quickly thaw something that big. For instance, the Eh-Vegas elk roasts spent three days thawing in my fridge before I could cook them.

Other faster methods include putting the item on the counter, in the sink, in the sink with cool water (not hot or warm), or microwaving. The counter works for beef, but I'd never do chicken that way. The sink without water is mostly just to keep it off the counter. The sink with water is frowned upon since it promotes bacteria growth (moist environment, still takes a couple hours). I've done the sink with water to finish thawing a whole chicken without problems though. The microwave method is fast, but you run a very real risk of cooking the edges of whatever you're thawing. I have yet to thaw chicken without microwave "boiling" parts of it, or ruin perfectly good steak.

No, what I do is use my oven. I preheat it to 200-250 degrees F, put the frozen meat on a sheet of aluminum foil with edges turned up to prevent spilling (I find baking sheets/pans heat up too much and cook the bottom), and put it on the middle rack. I let it sit with the oven still on for a couple minutes, and then turn off the oven. About 20-30 minutes later, I have a soft, thawed, UNCOOKED piece of meat. If I need to bring it to room temp (steak), I might leave it in longer. This works for one or two pieces of meat only though. If you have a dozen hamburger patties or are feeding the poker group, then they'll cool down the oven before it has a chance to thaw them effectively. You could crank up the heat more (but this risks cooking things), or leave it on the lowest possible setting for the duration, but I've tried neither of these.

Now the thing with my method is you can't leave the meat sitting around for hours afterwards as the warm oven environment will promote bacteria growth. While it's thawing, I suggesst prepping everything else so you can get to cooking as soon as possible. Since I use this method for steak, chicken breasts, sausages, pork chops, fish filets, etc., everything is generally fried, grilled, or roasted at a high temperature. I wouldn't use this for a roast or whole bird, or anything that would be delicately prepared at low temperatures afterwards.

Obviously, pre-cooked things are less of a concern when thawing. Mom's lasagna can be popped in the microwave and cooked away if you want. I prefer warming up frozen soup on the stove myself (it recombines better). TV dinners? Well, they never go bad (yay preservatives!) and can be cooked in 5 minutes.

I think I've exhausted what I know, mostly from my own experience. Bear in mind that I'm one of those guys who scoffs at a lot of best before dates (except on meat, milk and fresh bread) as ass-covering legal necessities. Most food lasts longer than the label says. The "use latex gloves and sanitize everything after looking at a raw chicken" school of thought is a bit overboard in my opinion as well. I take precautions (wash my hands after handling raw meat before touching everything else, and clean the counter with hot water and soap), but don't go overboard. A few germs and bacteria just make you stronger, right?


Jordan said...

Dude, that was just plain awesome. Everything I wanted to know and more. Thanks a ton.

lightning36 said...

Astin = The Hoyazo of Frozen Foods

jjok said...

excellent writeup.....about freezing.

It sounds funny considering the topic, but you're dead on.

I bought a deep freezer a few years back and have no regrets. It's easily one of the better money savers a person can get assuming the person can also plan out meals and eats primarily at home like me do nowdays.

And in this economy, paying $2.50 a pound for B/S chicken breasts sure beats the heck outta $5.....just don't freeze red meats that are supposed to be red. ;)

Astin said...

Lightning - I like to think of myself as the Jordan of frozen foods :).

JJ - For sure. It also makes organization way easier. My fridge-freezer now has stuff I can nuke and the chest has the more substantial items. No more digging through bags of bones and meat to find that soup from 6 months ago.

OhCaptain said...

One piece of advice that I just didn't see there, but is very important in chest style freezers is keeping them full. A full freezer will stay much more consistently cold then an empty one.

Uprights, where the door is vertical, need to have the door closed as much as possible. The cold air does literally fall out the bottom.

Like the upright fridge, keep the temperature sensitive items at the bottom.

I tend to organize my fridge so that items I grab repeatedly are front and center so I can grab and go. Less frequent items go to the bottom in the chest and the back in the upright.

My turkey method from today was a derivation of the Alton Brown Good Eats episode on turkey making. I must say...very simple way to make a tasty and juicy turkey.

BTW - Excellent write up!