Have you ever wondered if you're cooking vegetables well?

Recently, one of my clients asked me about strategies for cooking vegetables correctly. She often struggles in her kitchen, getting confused because she doesn't know how to cook vegetables. She cooks broccoli for too long and can never figure out the right cooking times for most of her produce. This dilemma was getting old. Who wants to eat mushy broccoli?

To answer her question, I dove into research. What is the common denominator when it comes to cooking any vegetable well?

I started with fiber content. Unfortunately, that went out the window because there doesn't seem to be a concrete link between fiber content and cooking time. For example, avocados have lots of fiber but don't need to be cooked for long (or at all!) to be delicious. So. That avenue is closed.

What about water content? It turns out that water content isn't a good common denominator either because most vegetables are high in water and yet require a wide range of cooking times.

This was getting frustrating.  What makes a vegetable a candidate for long or short cooking times?

The more I looked for an answer, the more intrigued I got. I had never learned this approach in any of my Culinary Institute of America classes, nor had I ever read one in a book or blog. Where could I go to get this information?

The tides began to turn after I stumbled upon a discussion of cellular structure and its impact on cooking times. As I poured over the book FOOD SCIENCE by Norman N. Potter and Joseph H. Hotchkiss, I realized I was on to something. The answer to the texture of vegetables and their respective cooking times could lie in their cellular structure.

Alas, dear cooking aficionados, there was no chart to illustrate this point anywhere. I took to the internet to see if I could find one and was subsequently buried in an avalanche of options. Sadly, the variations and inconsistencies prevented me from finding the perfect guide to cooking vegetables.

My efforts were not for naught, however, because I did come across an article about cellulose and the cell structure of vegetables. At this point, I was becoming sure that the common denominator to vegetable cooking times is cell structure.

Here's how I got there...

• Cellulose and the cell structure of vegetables are responsible for the amazing variety of structures we find in our vegetables.

• In addition to cellulose, there are also pectins and hemicellulose.

• Cooking softens cell walls, though sometimes the cell walls never become digestible. Don't worry; this is a good thing -- these are the sources of fiber.

• The older a vegetable is after it is picked, the less water it has in its cells and the less crisp it becomes.

• The water pressure in vegetable cells is called turgor. It can be reduced if a vegetable is frozen or cooked.

• The older a vegetable is before it is harvested, the tougher it will become.

• An older vegetable will not be as tender. Leaving it too long in the vegetable drawer or at room temperature will dehydrate it and make it lose crispness.

Click the image above to download the chart.

From here, I devised my system for determining vegetable cooking times: the chop test.

If a vegetable is physically hard to chop, then that vegetable will take longer to cook. Cook it until it is tender, and don't worry too much about overcooking. Stick a knife or fork into the vegetable. When that vegetable yields easily to such prodding, then it's done.

What are some hard-to-chop vegetables?

• Artichokes

• Beets

• Carrots

• Potatoes

• Pumpkin

• Rhubarb

• Rutabagas

• Sweet potatoes

• Turnips

• Winter squash

What are the best ways to cook them?

• Chop them up and roast them in the oven at 350 degrees Fahrenheit for one hour.

• Cook them in a pressure cooker according to the manufacturer's instructions.

• Chop, cover, and microwave them in 5-minute intervals until tender.

If a vegetable is easy to slice, then it will cook much more quickly. Cook gently until just crisp-tender, paying careful attention to doneness. These vegetables are more finicky than the hard to chop options -- overcooking will make them mushy and less palatable.What are some easy-to-slice vegetables?

•  Arugula

• Broccoli

• Broccoli Rabe

• Cabbage

• Cauliflower

• Cherry Tomatoes

• Eggplant

• Fennel

• Garlic

• Green Beans

• Onions

• Peas

• Peppers

• Snow Peas

• Spinach

• Sugar Snap Peas

• Summer Squash

• Tomatoes

What are the best ways to cook them?

• On a grill. Preheat your grill and either lay down a piece of lightly-oiled foil, placing sliced vegetables on top of it or use skewers instead and thread vegetable slices onto them, placing the veggie-laden skewers directly on the grates. Check veggies every minute or two and remove the second they get crisp-tender

• In a steamer basket. Bring a bit of water to a simmer in the bottom of a saucepan. Place a steamer basket in the pan, then top with sliced vegetables. Cover the pan and steam until veggies are crisp-tender, checking water levels and doneness every few minutes. Be vigilant!

• On the stovetop. Quickly sear or saute vegetables in a wok or saute pan with a little olive oil and seasoning.

Some vegetables should not be cooked because they are easy to slice and very high in water content. This is more of a cooking lesson than the rest, because ease of chopping is not a factor.What vegetables shouldn't be cooked?

• Avocado

• Cucumbers

• Lettuce

• Radishes

• Sprouts

What are the best ways to serve them?

• Tossed with vinegar and a dash of olive oil as a salad.

• Shaved thinly and served carpaccio-style.

• Sliced into wedges and served with dip.

Well, now that we've got the basics out of the way, it's time to talk exceptions. There are exceptions to every rule, after all. So, what's different here?Long-cooking greens are an exception because they are easy to cut but need longer cooking to make them tender and palatable. Then there are tomatoes, which mellow over time if you are making a sauce.So what do you think? Feeling inspired? If you'd like to try cooking these healthful veggies, here are some quick links to get you started!

Stay tuned! There's a lot more to come. Right now we're testing a new concept from the Science of Modern Cooking: a dip in a hot water bath to lengthen the shelf life of most fruits and vegetables, even lettuce and berries. What do you think? Have you tried it?

References:

1. Modernist Cuisine - Volume 3, Plants and Animals.

2. Vegetables and Fruits” from the book FOOD SCIENCE by Norman N. Potter and Joseph H. Hotchkiss. Published by Kluwer Academic/Plenum Publishers. New York

Click the image to download.

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