Washington - A typical Wednesday night at my house goes something like this: open refrigerator, take lettuce and other vegetables out of crisper, see that most of them are wilted, return them to refrigerator. Realise meat isn’t defrosted, call for takeaway.
That is followed by my Saturday morning routine: buy fresh vegetables, come home, open fridge, slide out crisper drawer, throw almost everything away, replace with new stuff.
I’m pretty embarrassed by the waste. When I buy meat, I use every bit of it, including the bones for stock. Why am I so careless with vegetables?
I’ve made a real effort to break this bad habit. I try to eat vegetables with every meal. Still, Swiss chard and romaine lettuce leaves droop and sag after a few days at home, and there are only so many stir-fries and soups one can make when carrots, green beans and asparagus get bendy. Even when I’m trying, vegetables often wilt before I can get to them.
With a firm resolve to save money, I’ve been on a mission to extend the “fridge life” of my vegetable staples. So I turned to the experts to learn more about how to revive what I’ve got and better store what I buy.
“Water is everything.”
That’s what grocer Bernard tells me. He’s right. We all learnt in high school biology that the human body is about 60 percent water.
Plant foods beat us: most fresh vegetables in a typical diet are more than 90 percent water by weight, according to Nathan Myhrvold and the team who wrote the epic food science and technology tome, Modernist Cuisine: The Art And Science of Cooking (The Cooking Lab, 2011).
For example, they found that a carrot is roughly 88 percent water, nearly the same proportion found in milk. A fresh cucumber contains a higher proportion of water than some mineral-rich spring waters. Swiss chard is 94 percent water.
In Keys To Good Cooking: A Guide To Making the Best of Foods And Recipes (Hodder and Stoughton, 2010), food science expert Harold McGee writes that fresh vegetables and herbs gradually deteriorate as they use up their limited water reserves after harvesting. That makes sense.
But can you give them a little boost before they cross over to the rotten side, and if so, how?
Consumer advice about reviving vegetables runs the gamut: room-temperature water versus iced water; submerging the whole vegetable or soaking just the ends; adding salt, sugar or vinegar to the water. Chefs, food companies, scientists and food bloggers offer a variety of methods juggling time, temperature and those additives, with the one common factor being water.
Kathleen M Brown, professor of plant stress biology at Penn State University, teaches a post-harvest physiology class and has researched this topic. Her advice: all you need is water.
“Additives actually reduce the difference in osmotic potential between the vegetable and water and reduce the rehydration rate,” she says.
“Besides, you don’t need those flavours.”
Air and water temperature matter during the revival process, Brown advises. “When the air temperature is lower, the vapour pressure deficit – the driver of moisture loss – is smaller.”
Brown tells me I should soak vegetables in cold water from the tap to revive them, and to do so in the refrigerator instead of in my warm kitchen.
For vegetables that have a heavy cuticle or waxy exterior layer that may not admit water as quickly – Swiss chard and celery are examples – Brown suggests trimming the stems and putting them in a glass or vase of water, as you would fresh flowers.
How do you know when they’re refreshed? “When the vegetables are well hydrated, there is a higher pressure in the cells, and they break and release moisture more easily when you chew, so they seem crisp,” says Brown.
Can vegetables be over-hydrated? Sort of.
Gardener and chef Deborah Madison, whose latest book is Vegetable Literacy (Ten Speed Press), cautions that when you wash or revive leafy greens such as lettuce, kale or chard, you need to dry them thoroughly if you’re not going to use them right away.
Water remaining on the outside invites bacteria. In fact, Madison breaks apart her lettuce and other leafy greens, rinses and dries them, then stores them in a plastic bag with a clean, dry dish towel or paper towels to absorb any remaining moisture on the leaves.
The challenge for many consumers, myself included, is that crisper drawers are at the bottom of the refrigerator, and out of sight is out of mind.
Madison keeps flours, grains, nuts and dried fruit in her refrigerator crisper drawers – not vegetables.
“I store vegetables in plastic bags on the shelves in my fridge, and it works just fine,” she says. Keeping them in plastic bags provided by vendors gives vegetables a better chance at lasting longer.
It’s common sense that the foods kept at eye level are those you will use most in cooking, says Madison.
If you’ve lost sight of vegetables and they have wilted, it’s worth trying to rehydrate them. But if they are past the point of no return – if they have changed colour, are covered in dark spots or have become discoloured, liquefied, or slimy or have obvious bacterial or mould growth – discard them.
Better yet, “compost them”, says Madison. “Returning them to the earth should make you feel less guilty.” – The Washington Post