If you're anything like me, you probably have a bag - or three - of old frozen vegetables sitting in your freezer. Forgotten, unloved, possibly freezer-burned. But these grocery staples definitely deserve more appreciation, especially as cooler months creep closer, diminishing access to the fresh, local produce many of us rely on.
"A lot of people pooh-pooh them," says US cookbook author Bruce Weinstein, who writes recipes with his husband, Mark Scarbrough. "The convenience factor is ridiculous."
The quality is not something to dismiss either, Weinstein says, as what you can find in the freezer section during the off-season is often better than what's in the fresh produce section. Food meant to be frozen is picked at optimal ripeness and processed, often within hours of coming out of the field. That means it can beat out items trucked in from far away in terms of both taste and carbon footprint, especially for vegetables brought up in winter from the opposite hemisphere.
Here's what you need to know about putting nutritious frozen vegetables to good use.
Water expands as it's frozen, and that process affects vegetables. Those ice crystals break the cellular structure of the produce. "Some people say that ruins the vegetables," Weinstein says. It's true if you eat the vegetables uncooked, when you may get mushy food that ends up releasing a lot of water. But as cooking is intended to drive off moisture anyway, using frozen vegetables means you're already a step ahead in eliminating some of the water you'd be burning off by roasting, sauteing, etc. "It can save a lot of time on both ends of cooking," Weinstein says.
The convenience factor [of frozen vegetables] is ridiculous.Cookbook author Bruce Weinstein
That initial breakdown is why some frozen vegetables hold up better than others. Look for options that are lower-moisture and sturdy enough to not be rendered into pulp by ice. Some of Weinstein's favourites include corn, artichokes and cauliflower. Cook's Illustrated adds peas, lima beans, pearl onions and spinach to its recommended list, with broccoli, carrots and green beans on its acceptable roster, especially if you're incorporating them into dishes where a crisp texture is not crucial. The magazine is less keen on high-moisture vegetables, such as bell peppers, snow peas, snap peas, asparagus and mushrooms.
Also think about the types of frozen vegetables that can save you time - peeled pearl onions, prepped artichoke hearts, shelled edamame and cubed butternut squash.
Unlike meat, which is sold airtight or can be frozen airtight when you wrap or vacuum seal it yourself, frozen vegetables in bags include air, and therefore moisture, in the packaging. "I think they have a more limited shelf life than meat," Weinstein says. More moisture, coupled with the cycles a self-defrosting freezer goes through, can cause freezer burn and wreak havoc on the texture of food. For those reasons, he prefers to use frozen vegetables within a few months. Aim for a colder part of your freezer, if you can, away from the door. If you open and use part of a package, try to cook the rest within a week.
First, a necessary word about food safety. "Most frozen foods are intended to be cooked, and the safest way to consume any product is to carefully follow the package cooking or preparation instructions," Alison Bodor, president and chief executive of the American Frozen Food Institute said earlier this year. Don't assume that the washing and blanching process kills pathogens, as frozen produce, just as fresh, has at times been linked to outbreaks of food-borne illness here and abroad. Yes, you may have eaten uncooked frozen vegetables and been fine, but know that there is some risk.
The first step to cooking may involve thawing, especially if the moisture released by frozen vegetables will be a problem. For Weinstein, those situations include stir-fries and curries. He likes to thaw vegetables before adding to a pot of soup or stew, as straight-from-the-freezer food can drop the temperature and cause you to overcook the food when you're forced to cook it longer to bring the temperature back up. Thawing and wringing water out of frozen spinach is almost always necessary, unless you enjoy soggy lasagne. Extra moisture can prove problematic in dips and frittatas, too.
Weinstein says you can let your frozen vegetables thaw overnight in the refrigerator. If you're using a small amount of smaller-size vegetables, as with the corn and peas in a fried rice recipe, a brief stint on the counter while you prep your other ingredients is sufficient.
Thawing is not always necessary. The Kitchn website suggests roasting vegetables straight from the freezer, in a hot oven on a preheated baking sheet, with plenty of oil. They can work in soups or stews, with a few caveats. Weinstein is OK chucking them into the pot for a soup that's going to be pureed, for example, since overcooked vegetables won't matter. Other recipes may suggest adding frozen vegetables in the last few minutes to just heat them through, which will prevent them from turning to mush and changing how the rest of the dish cooks.
If you're using frozen vegetables in a multicooker or pressure cooker, it may take longer to come up to pressure. That's one reason Weinstein and Scarbrough place frozen vegetables on top of the noodles, away from the liquid, in a lo mein recipe they included in their From Freezer to Instant Pot cookbook. In a chop suey recipe, they add still-frozen vegetables to the cooked dish, where they are cooked by the residual heat and a quick boil.
Weinstein says he prefers using frozen vegetables as an ingredient in dishes rather than on their own as a side. Even if you're not eating the vegetable straight up, you may want them cooked through if you're, say, adding them to a grain salad or burrito. A good first step is to read the instructions on the side of the bag, which often include microwave or stove-top options. I tend to overcook frozen vegetables in the microwave, especially if I'm using only part of a bag, but I still prefer it to boiling, which can lead to mushy, waterlogged vegetables that also lose some of their nutrients. Steaming is a nice middle-of-the-road option, with a moist but not too moist environment that doesn't take very long, either.
So what dishes are prime candidates for frozen vegetables? We've already touched on soups, stews and stir-fries. Try stirring peas and/or carrots into mac and cheese (maybe my/your kid won't mind?). Frozen vegetables can shine in risotto, too, according to Taste magazine in the US. Food 52 website recommends adding them to the mix when you're making vegie burgers (corn), dumplings (edamame) and gnocchi (spinach). The site says greens can be swirled into yoghurt or sour cream for a dip, or mushy and mashed vegetables (carrots, squash) or spread on toast. Try making your own flavoured hummus with cooked, pureed frozen vegetables.
The Washington Post