Is it True that You Shouldn't Cut Lettuce with a Knife? And is Iceberg Devoid of Nutrients?

Posted by Eric Troy on 22 Feb 2013 02:35

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No and no. The frequent admonishment to never cut lettuce with a knife, lest the cut edges turn brown faster than hand torn lettuce leaves, is a myth. Many cookbooks still carry the statement that a knife may "bruise the leaves." This myth seems to have been based on the belief that hand tearing will tear the lettuce along natural seams and thus damage less cells, limiting their exposure to oxygen, which turns them brown. But this isn't true and tearing lettuce does not damage less cells than cutting the leaves with a knife. It really will make no difference whatsoever which method you choose, and both will turn brown at the same rate. Before we go further, keep in mind that introducing bacteria, via the blade, to the cut edges of lettuce that you intend to store for a period of time, is a different subject, but one that is more of interest to commercial bagged lettuce processors than home cooks.

Torn Lettuce Isn't All It's Cracked Up To Be

Sometimes hand torn lettuce is better but at other times, uniformly cut lettuce is nice. Many "fancy" restaurants seem to have taken this myth to heart, producing green salads that have lettuce pieces of all different sizes, making it difficult to eat. This happens with Caesar salad quite a lot, which really should have nice uniform square pieces of Romaine lettuce, if you ask me, regardless of how it may have been done in the past. Also, you couldn't have an iceberg wedge without a knife. But this article isn't about whether salads should be chopped or not, which, frankly, I could care less about. You can throw your salad ingredients in a blender and slurp them through a straw, for all I care. Tear it, cut it, bash it with a hammer, use it for toilet paper, I don't care. This is about the myth of lettuce being damaged by cutting because I enjoy busting myths. Call it a hobby.

Romaine lettuce

Romaine Lettuce

Romaine lettuce

Romaine Lettuce

Incidentally, when dealing with a whole head of green lettuce such as Romaine or a leaf lettuce variety, you can actually store your leaves longer if you go ahead and cut or tear them away from the stem, and wash or dry them, making them ready for use. Just make sure to dry them well, with paper towels or even better, in a salad spinner. As hinted at in the opening paragraphs, if you cut them, a clean knife might be a good idea. Then, store them in a bag lined wit paper towels to absorb any excess moisture, which will cause the lettuce to decompose more quickly. Don't fall for the mistaken instruction that the paper towels should be damp to retain moisture, as this will only hasten the demise of your lettuce. There are also green fabric bags you can buy to store your lettuce or other greens, which work well. Romaine will last longer than most leaf lettuces (red leaf, butterhead, curly leaf, etc.) which will wilt terribly within 4 days, at best.

Crisp head lettuces, of which iceberg is the most well-known, will hold up the longest and can do well on it's own with no preparation, for a while. It is the superior storage qualities, and hence the ease of shipping, which made iceberg so readily available, and hence so popular, long before other varieties were commonly found in grocery stores.


Iceberg Lettuce
image by Rasbak via wikimedia


Iceberg Lettuce
image by Rasbak via wikimedia

Is Iceberg Lettuce Really So Bad?

Since Romaine and leaf varieties of lettuce have become so widely available, our treasured iceberg lettuce, with its leaves perfect for hamburgers and sandwiches, its crisp texture and taste that doesn't bully a salad, has been much maligned. It's tasteless, mostly water; it's a nutritional pauper, they say. Well, I beg to differ.

The iceberg is bad crowd seems to sustain this smear campaign simply because they think it makes them look more cultured. Iceberg has lots of things going for it, and one of those is its lack of strong flavor! Sometimes, what you want is texture, and not taste. For some reason, people also like to say the iceberg lacks texture, but this is just silly. It has a delicate, crisp texture. This is what makes it so perfect for a hamburger. As well, the crisp texture, kept in wedges, can be just the thing when the right dressing is used. The wedge salad with blue cheese dressing and bacon is a standby in steak houses (a "BLT Wedge Salad) and before you scoff, consider that when you add flavors to other lettuces, they compete, but when you add flavors to iceberg, the iceberg acts simply as a crispy carrier. And you can even cook with iceberg! Try out this recipe from Katie's Cucina for BLT Wedge Salad with Creamy Pepper Dressing.

And nutrition? Well I don't usually do nutrition in this blog, but in the interest of defending iceberg, I'll compare iceberg to Romaine, per 100 grams, by weight. Keep in mind that the outer leaves of Romaine are more nutritious than the inner leaves, and this analysis assumes an average composition.

Nutrient Unit Romaine, 100g Iceberg, 100g
Calcium mg 33 18
Iron mg 0.97 0.41
Magnesium mg 14 7
Phosphorus mg 30 20
Potassium mg 247 141
Sodium mg 8 10
Zinc mg 0.23 0.15
Vitamin C mg 4 2.8
Thiamin mg 0.072 0.041
Riboflavin mg 0.067 0.025
Vitamin B-6 mg 0.074 0.042
Folate µg 136 29
Vitamin B-12 µg 0.00 0.00
Vitamin A µg 436 25
Vitamin E mg 0.13 0.18
Vitamin K µg 102.5 24.1

It's clear that Romaine is some great stuff. The two nutrients that leafy green vegetables are held in such regard for, calcium and Vitamin A, it has in abundance. Iceberg can't compete. And it lags behind in other micronutrients. But is it "almost completely devoid of nutrients," as is so often reported? No, clearly not. To put this in perspective, bring Romain down a notch by considering the RDI (Reference Daily Intake) of calcium, of 1000 mg. You'd have to eat over 3000 grams of Romaine to get that, over 6.5lbs. Sure, that's a lot better than 12lbs of iceberg lettuce, but either way, you are going to be in some GI trouble. Romaine is better than iceberg, but it's not a miracle. This can be a good approach, by the way, to help you cut through some of the overwrought claims about the superior nutritional nature of one vegetable over another. Consider it's percent of contribution of key nutrients to a "daily allowance" rather than just comparing one raw number to another. By those standards, no lettuce can really make or break you.

Looking at the actual values, above, it seems that the nutrition books frequently get it wrong, by saying that Romaine has up to six times as much vitamin C, it doesn't even contain twice as much. And neither contain a lot. It's with beta carotene that Romaine really shines, though, and absolutely squashes iceberg.

So, iceberg is not as nutritious as Romaine. In fact, it has the lowest nutritional value of all the lettuces. But it does have some nutritional value, and that nutrition comes in with low energy-density. Also, it has uses that it is quite suited for. If you don't believe me, try an Asian lettuce wrap made with Romaine and see if you don't want to get with some iceberg again.

How Did Iceberg Lettuce Get Its Name, Anyway?

As above, iceberg owes its popularity to economics. This firm head lettuce was easier to ship and got to the store less damaged. We (used to) love iceberg because we grew up eating it, being that it was pretty much the only lettuce many of us ever saw, as children.

Iceberg was introduced by W. Altee Burpee Company in 1894. In the 1920's, the company shipped by train covered with crushed ice. People saw the boxes coming with all their heaps of crushed ice and they said "The icebergs are coming." Or so the story goes. The lettuce came to be called iceberg lettuce because of this but before, it was called Crisphead lettuce.

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