Monday, September 13, 2010

It's all about the tomatoes

If there's one piece of produce that keeps coming up in local food issues, more than any other crop, it's the powerful tomato.

Tomatoes are a staple ingredient in modern cuisine, integral in salads, sandwiches, soups, stews, sauces and condiments. The United States Department of Agriculture estimates the average American eats 22 pounds of tomatoes each year, and half of that is in ketchup and tomato sauce.

Tomatoes are also a wonderful example of the positive effects globalization can have on culture. The Etruscans brought pasta with them when they were assimilated into Roman culture and the Spanish brought the first tomatoes to Italy in 1522 all the way from Peru. This mixing of culture and plant life has shaped Italian cuisine into something incredible, something that would have been impossible if they had remained restricted to local, native ingredients.

Locavores claim that local tomatoes taste much better than what the grocery stores sell because the delay between harvesting and consumption can take a week. Tomatoes that are bred for transportation have to be tougher and thus blander, while the fragile "heirloom" tomatoes that local farmers sometimes grow taste much better.

I've expressed skepticism at that idea of heirloom tomatoes tasting better, as people's expectations can trick their taste buds. However, a Freakonomics blog interview with agricultural economist Daniel Sumner brought up this pesky, inconvenient exchange:

Q: Do you have a personal garden at home? If so, what are your major crops and why?

A: We have lemons, plums, peaches, nectarines, oranges, and apricots in the backyard. We used to grow tomatoes, but the local tomatoes here are quite tasty and available during the same months when our backyard tomatoes are producing. Also, any friends and neighbors are happy to share their crops during the peak seasons.

Sumner is critical of the environmental and economic arguments of the localist movement, but his specific mention of tomatoes showed me that its likely there are some taste differences in specific crops. In the same interview he also mentioned strawberries:

I love to go out and buy strawberries from the little two-acre field a couple of miles from my house. Some days by the time I get there he has sold out of his daily harvest from that field and he will try to sell me the bigger prettier ones from his “other field.” But one taste is enough to make me wait for a day.
Unlike tomatoes, strawberries are something I will eat unprepared and after eating a few local strawberries I had to admit that they do taste better. Unquestionably.

This lends credibility to the taste hierarchy of tomatoes. I'm spending a little more time on this small aspect than I normally would because it is an admission of a flaw in something I've written before, and I don't want to rush over it.

What are heirloom tomatoes?

Having heard the term "heirloom tomato" thrown around so long, I finally looked it up. From CNN's food snob blog Eatocracy:

Here's the deal. Heirloom seeds come from plants that have remained genetically unchanged and have been open-pollinated (by insects, birds, wind, etc.) for at least 50 - or some say 100 - years. This means no hybridizing with other varieties of plants. This has its ups and downs.

On one hand, the Amish Paste or Beefsteak tomato you're biting into tastes the same as it would have in your grandfather's day. It hasn't been genetically modified to select durability or uniform appearance over flavor, so while it might be lumpy and bumpy, and appear any color from moon-pale, purple, pink or black to gold, green, yellow, brown and zebra-striped, chances are it's going to be luscious, or growers wouldn't have bothered propagating the line.

On the other, a cruelly short shelf life and thin skin can cause havoc for a farmer who's looking to transport a harvest, and many varieties haven't been bred for disease resistance - hence the devastation wrought by last year's blight. Also - some people just like a uniformly round, red, taste-free tomato.

Let them have the bland, beauty pageant supermarket 'maters. We'll hold out for the ugly stuff.
Organic blogger Gary Ibsen, who specializes in tomatoes, makes the case for heirloom tomatoes less about taste and more about warding off the apocalypse:

In the past 40 years, we've lost many of our heirloom varieties, along with the many smaller family farms that supported heirlooms. The multitude of heirlooms that had adapted to survive well for hundreds of years were lost or replaced by fewer hybrid tomatoes, bred for their commercially attractive characteristics.

In the process we have also lost much of the ownership of foods typically grown by family gardeners and small farms, and we are loosing the genetic diversity at an accelerating and alarming rate.

Every heirloom variety is genetically unique and inherent in this uniqueness is an evolved resistance to pests and diseases and an adaptation to specific growing conditions and climates. With the reduction in genetic diversity, food production is drastically at risk from plant epidemics and infestation by pests. Call this genetic erosion.

The late Jack Harlan, world-renowned plant collector who wrote the classic Crops and Man while Professor of Plant Genetics at University of Illinois at Urbana, wrote, "These resources stand between us and catastrophic starvation on a scale we cannot imagine. In a very real sense, the future of the human race rides on these materials. The line between abundance and disaster is becoming thinner and thinner, and the public is unaware and unconcerned. Must we wait for disaster to be real before we are heard? Will people listen only after it is too late."

It is up to us as gardeners and responsible stewards of the earth to assure that we sustain the diversity afforded us through heirloom varieties.

So it sounds like heirloom tomatoes could provide a bulwark against diseases and carry the last genes of tasty produce.

A Scientific American article from last year says otherwise. It turns out the heirloom tomatoes have little chance against disease and their taste is a result of growing styles - not genetics:

Famous for their taste, color and, well, homeliness, heirloom tomatoes tug at the heartstrings of gardeners and advocates of locally grown foods. The tomato aficionado might conclude that, given the immense varieties—which go by such fanciful names as Aunt Gertie's Gold and the Green Zebra—heirlooms must have a more diverse and superior set of genes than their grocery store cousins, those run-of-the-mill hybrid varieties such as beefsteak, cherry and plum.

No matter how you slice it, however, their seeming diversity is only skin-deep: heirlooms are actually feeble and inbred—the defective product of breeding experiments that began during the Enlightenment and exploded thanks to enthusiastic backyard gardeners from Victorian England to Depression-era West Virginia. Heirlooms are the tomato equivalent of the pug—that "purebred" dog with the convoluted nose that snorts and hacks when it tries to catch a breath.

"The irony of all this," says Steven Tanksley, a geneticist at Cornell University, "is all that diversity of heirlooms can be accounted for by a handful of genes. There's probably no more than 10 mutant genes that create the diversity of heirlooms you see."


The selection of these traits has taken a toll on the heirloom's hardiness: They are often plagued by fungal infections that cause the fruit to crack, split and otherwise rot quickly. Wild plants must continuously evolve to fend off natural pathogens, points out Roger Chetelat of the Tomato Genetics Resource Center at the University of California, Davis. But in their quest for size, shape and flavor, humans have inadvertently eliminated defensive genes. As a result, most possess only a single disease-resistance gene.

Perhaps that's the price to pay for a good, flavorful fruit? Hardly, Chetelat says, because the heirlooms' taste may have less to do with its genes than with the productivity of the plant and the growing environment. Any plant that sets only two fruits, as heirlooms sometimes do, is bound to produce juicier, sweeter and more flavorful fruit than varieties that set 100, as commercial types do. Plus, heirlooms are sold ripened on the vine, a surefire way to get tastier results than allowing them to mature on the shelf.
So all of this fawning over heirloom tomatoes is about a slow, land-intensive and inefficient growing style, where each vine is only allowed to grow two tomatoes. This is essentially a luxury good, like a hand-made pair of shoes, where a skilled craftsman charges much more than a factory-produced version for those who can afford it. Saying everyone should only eat heirloom tomatoes is like saying everyone should eat caviar and turn up their nose at anything less.

I'm reminded of what Jeffrey Steingarten wrote in his chapter Salt Chic in It Must've Been Something I ate. Gourmets claim that expensive sea salt gives a superior taste to iodized salt, but when given a taste test with the salt in a prepared entree, they were unable to tell the difference. Food snobs still make a huge deal out of the ingredient, but it loses its edge when combined with a flurry of other tastes and textures.

Tomatoes will stand out in a salad or when eaten solo, but the premium someone pays for a luxury tomato is wasted when it's cut up and incorporated into a dish with ten other items.

Local foods suffer from seasonal availability

Because the tomato is the unofficial mascot of the locavore movement, I did the math to see what fraction of the year they can actually get fresh, natural tomatoes here in Maine. The answer is a mere one-quarter of the year.

Growing season in Maine is from May to early October, or about five months. The plants take a minimum of 58 days to produce edible fruit, so the edible season is down to just over three months.

This season can be extended using heated greenhouses, but this compromises the philosophy that people should only eat where food can be grown outside as nature intended. It's also damaging to the environment to spend energy heating plants when they can be grown in other parts of the world outside year round.

The solution for committed locavores is to preserve the tomatoes for the rest of the year.

It's rather odd to realize that the relentless example local food activists always turn to in the tomato is such a brief phenomena out of the year. This one-quarter of the year figure assumes locavores will be picking tomatoes out of their gardens each week. In practise, its much less because tomatoes lose most of their flavor a few hours after they are picked, according to a Science Wire article:

Once a fully ripened tomato is picked, its flavor deteriorates quickly. There are more than four hundred compounds, aromatic as well as flavorful, in the fruit. They all act in concert to let you know you are eating a tomato rather than a turnip. After the fruit is picked, these compounds rapidly deteriorate. Just two hours off the vine, a tomato has lost some of the factors that make it taste so good. The flavor also suffers if a ripe tomato is kept for more than a few hours in a refrigerator.
Most farmers' markets are open once a week, so assuming those tomatoes are picked right before they are sold, those localvores only get the benefit of fresh tomatoes once a week during the growing season, or about 14 days out of the year.

So while I admit there are some taste preferences to be found in heirloom tomatoes, the same can be said for a $90 box of chocolates. It's up to the consumer to decide if the taste is worth paying for.

No comments:

Post a Comment