To Refrigerate or To Not Refrigerate; That Is the Question

Chill, Baby – Or Not

Standing tall in the average American kitchen is the appliance that changed the world about a hundred years ago. I'm talking about the refrigerator, of course. Or as my grandmother called it to her dying day, the “icebox.” Or, as Alton Brown says, the “chill chest.” Whatever you call it, the technology has certainly changed the way we preserve food.

Used to be, drying or salting or maybe pickling were the only ways to make food last more than a few days. People who lived in icy places recognized another way, but that method was difficult to replicate indoors. That is until somebody came up with the idea of building a wooden box and lining it with tin or zinc and stuffing that lining with cork, sawdust, straw or some other form of insulation. Then they stuck another box or a tray on top and put a big block of ice in that box or tray. The cold produced by the melting ice would sink – because cold air sinks and hot air rises – cooling the interior of the insulated box. And the ice box was born.

That worked well until the early1900s when somebody else thought, “there must be a better way” and came up with one. And the development of the modern refrigerator was underway. By the 1930's, home refrigerators had become ubiquitous, putting people like my dad, who worked in an icehouse, out of work, but vastly improving the quality of life – and of food – for most people.

Some folks began throwing everything in the ol' icebox/refrigerator on the theory that if it's good for some things, it must be good for everything. Not so much. To refrigerate or to not refrigerate; that is the question. And here are some answers.

Obviously, anything that's going to spoil or “go bad” needs to be refrigerated. Meat, for example. Or leftovers. Those are kind of no brainers. But it's not always a matter of maintaining food safety; sometimes it's a case of preserving food quality. And that's where a lot of people go off the track. Especially when it comes to produce. Carrots, celery, lettuce – pretty much anything you find chilled in the produce section of the grocery store should remain chilled once it gets home. But there are some items that fall into gray areas as well as some that should absolutely not be refrigerated.

Apples fall into the gray area. Some people like 'em cold and some prefer them at room temperature. And that's fine if you're dealing with fresh-off-the-tree fruit. Pick some apples and stick them in a nice basket on your table and you have both a quick source of snack food and a nice centerpiece. But if you do your apple picking at the supermarket, chances are those apples were in long-term cold storage before they hit the market. According to Purdue University, “apples are best stored at 30°- 32°F, with a relative humidity of 90 percent and some air circulation. These conditions provide the greatest delay in the normal ripening and aging process of the fruit. Such conditions are necessary because an apple is not dead at the time of harvest. It remains a living, respiring organism and continues to take in oxygen and give off carbon dioxide and another gas, ethylene. Since the apple is no longer receiving nutrients from the tree but is still respiring, it must use up the food it has stored over the growing season. As this food is gradually used up during storage, the sugar, starch, and acid content of the apple changes. Eventually the tissues break down (a process enhanced by ethylene gas), water is lost, and the apple withers and decays. The low temperature, high humidity, and exchange of gases through air circulation serve to slow those natural events as much as possible.”

The nice, bright, “fresh” apples you just bought at the store may have been living in cold storage for the last year or so. And when you bring them home and put them in that pretty basket on the table.....well, they begin to show their age pretty rapidly. Oh, they're still “good” in that they're not overtly rotten, but they'll get old and mealy a lot quicker than if you keep them stored under the conditions to which they've become accustomed – i. e. refrigerated.

Some folks refrigerate bread thinking it will preserve the quality by retarding mold growth. And that's true. But it's also true that refrigerating bread will hasten the staling process. Bread goes stale for two reasons; loss of moisture and the retrogradation and recrystallization of starch. There's a pages-long scientific explanation of the process, but it boils down to this: cold reforms the starches in the bread and makes them harden. Even sealed loaves of bread will stale in the cold. Freezing is another matter. Freezing actually retards the process. So here's the takeaway: if you're afraid of your bread going stale, leave out just enough to use for a couple of days and stow the rest in the freezer.

Eggs are another good example of a gray area. In Europe, eggs are left out in baskets on tables and counters. In America, they have to be refrigerated. Why? Because European egg producers don't wash their eggs the way American suppliers do. American eggs are so thoroughly cleaned with hot water and a chlorine spray before they are packaged that the egg's natural outer protective coating – the cuticle – is washed away. Since eggshells are extremely porous, this means any stray microscopic bugs lurking about – particularly salmonella – can get an easy ride into the egg's interior. Hence the need for refrigeration. Farm-fresh eggs that don't undergo such rigorous cleansing can safely be left out, but bear in mind that an egg's freshness is also preserved by refrigeration. Experts say an egg will age more in one day at room temperature than it will in a week in the refrigerator. And in spite of the dimpled little trays in the door, eggs should be refrigerated in their cartons in the coldest part of the fridge. Door storage exposes them to too many changes in temperature and too much jostling as the door is constantly being opened and closed.

One thing that most people don't think to refrigerate but probably should is nuts. There's nothing wrong with keeping them in the pantry, but because nuts contain oils that can go rancid, refrigerating them will preserve flavor and quality for a good bit longer.

I've opened refrigerator doors and have been astonished at what I've seen stowed away in there. Coffee, sugar, flour, potato chips, even breakfast cereal. There's one word for that practice: STOP! And another word to explain why: moisture. There's no place like the refrigerator to create moisture through condensation. In an ideal world, the inside of a refrigerator would be perfectly cold and dry. But this is the real world. Every time you open the door, moisture gets in. If your door seal is not perfect, moisture gets in. If you have open containers of food or beverages in the refrigerator, or moisture-laden foods like celery and lettuce and such, they are all releasing natural moisture into the interior of the fridge. And what makes dried foods like crackers and cookies and potato chips get stale the quickest? Yep. Moisture.

The National Coffee Association will be the first among many to tell you “it is important not to refrigerate or freeze your daily supply of coffee because contact with moisture will cause it to deteriorate. Instead, store coffee in air-tight glass or ceramic containers and keep it in a convenient, but dark and cool, location.” They say freezing bulk quantities of coffee in small batches is okay as long as you don't return them to the freezer or fridge after you've taken them out.

Sugar will harden up when exposed to the tiniest bit of moisture. All you need is an airtight container in a cool, dry spot. No refrigeration required.

In spite of what Aunt Sally might say, white flour does not need to be refrigerated. Processed all-purpose flour will last a long, long time sealed up in the pantry. You'll probably use it up way before any spoilage can occur. Not so with whole wheat flour, however, which still contains the bran and germ. Oils in those elements can go rancid within a fairly short time, so if you're not blazing through your supply of whole wheat flour, refrigerating it is a good idea.

Potato chips? Really? Unless you just like cold chips there's no reason whatsoever for refrigerating them. You might think you're keeping them nice and fresh, but the opposite is true. Remember moisture? You might as well leave the bag open and store it in the bathroom next to the shower. And besides, an open bag of potato chips in my house is lucky to survive more than forty-eight hours. They wouldn't get stale in that time frame unless I really did store them in the bathroom next to the shower. Just close the bag, pressing out as much air as possible as you do so, and seal it up in – you guessed it – a cool, dry place.

And as far as refrigerating cereal, the same principle applies to Cheerios as to potato chips.

Tomatoes are big refrigerator no-nos. It's a topic for much debate, but science is on the side of keeping them out of the chiller. Chemically, the flavor in a tomato comes from a combination of sugars, acids and aroma-producing compounds called volatiles. These volatiles are most active at “room temperature” – sixty-eight to seventy-two degrees. My refrigerator stays at around thirty-seven degrees, as should yours. At that temperature volatiles start breaking down quickly. And it's not just the flavor that gets compromised. At temps below fifty, the actual structure of the fruit begins to soften and pit. If you like your tomatoes mushy and flavorless, the refrigerator is the perfect place to achieve that end.

Melons, like honeydews, watermelons, and cantaloupes, don't do well in the refrigerator. At least not whole ones. Different story once they're cut. Cut melons can be refrigerated for three or four days. I know, I know......you saw a website that said it was okay to refrigerate melons. But recent findings by the USDA show that the antioxidants in them hold up better at room temperature. Can you refrigerate them? Yes. Should you refrigerate them? No.

Potatoes aren't happy in the refrigerator either. Cold breaks down starches, affecting both the flavor and the texture of the potato. The starches turn to sugars and impart a weirdly sweet taste when the potato is cooked. These sugars also make the potato develop dark spots in the flesh. So if you want baked potatoes that are yuckily sweet and dark, go for it. Store your spuds in the fridge. Otherwise, a cool, dark place is where they'll be happiest longest.

Onions should stay out of the fridge, again unless they're cut. Whole onions get soft in the refrigerator and can turn moldy. Condensation, you know. And besides, they're smelly and love to share their smelliness with your butter, your eggs, and pretty much everything else in the box. If you cut an onion and don't use it all, you can stick the unused portion in a covered container and refrigerate it for a few days. Otherwise, onions like warm, dry places.

By the way, keep your onions and your potatoes far away from one another. They are great cooked up together in a hash brown casserole, but they don't play well together in their raw state. Onions are high ethylene gas producers and if you want to watch your spuds sprout practically overnight, store 'em near the onions.

Garlic, avocados, citrus fruits, and bananas should all avoid the inside of a refrigerator, too. Unless you really like the jet black banana look. Oh, they'll be okay to eat, but one look and you won't want to. And you can refrigerate berries, but they'll actually spoil more quickly than if you leave them out and just eat them real fast. As I said earlier, pretty much anything your grocer sells unrefrigerated should stay that way once you get it home.

Here are a final few yays and nays.

Once opened, ketchup will keep either way in the short run, but it's better refrigerated if you're not using it regularly. Same goes for mustard. Ketchup and mustard will last a month or two unrefrigerated. Refrigerated ketchup is good for six months or so and refrigerated mustard keeps for about a year.

Mayonnaise and dairy-based condiments should be refrigerated after opening. Relishes and other things made from fresh vegetables likewise.

Most oils are fine in cool, dark places. It won't hurt to refrigerate them, but they don't need it. I remember one winter when the power went out and the temperature in my kitchen dropped into the low fifties. The olive oil in my pantry got cloudy and a little sludgy. But when the room warmed back up, the oil cleared up and was fine.

Acidic, salty, or extremely sweet products are okay stored outside the fridge. Soy sauce, Worcestershire, vinegar, etc. need no refrigeration. Same goes for honey, molasses, and corn syrup. Some jams and jellies go either way. Most, especially those with two-thirds or more sugar, are okay in the pantry. However, some require refrigeration. Check the label.

Maple syrup is a touchy issue. I just checked the labels on the bottles in my refrigerator and both say “no refrigeration required.” BUT......both are “pancake syrup” not real maple syrup. Aunt Jemima and Log Cabin. One has HFCS (high fructose corn syrup) in it, a fact I did not notice when I bought it or I wouldn't have. But even the non-HFCS syrup contains corn syrup, sodium hexametaphosphate, sodium benzoate, sorbic acid and phosphoric acid, so nope, there's definitely no need to refrigerate those. Pure maple syrup, like honey, will crystallize in the refrigerator. On the other hand, it'll get moldy if you don't refrigerate it. Some people say you can just boil it lightly and skim off the mold, but.......no thanks. Producers associations in Vermont and Massachusetts say unopened maple syrup is relatively shelf stable but recommend refrigeration after opening.

Okay, this isn't a comprehensive list by any means, but it'll have to do for now. I have to go sort my produce. The onions are gassing the potatoes and making them cry their eyes out. So chill baby – or not.