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"The Botany of Desire" Documentary, TONIGHT at 8pm on PBS

Update: the entire documentary is now available online for free!

A new PBS* documentary, The Botany of Desire, premieres Wednesday night (tonight!) at 8pm on PBS stations throughout the US. It's based on the popular Michael Pollan book of the same name, and I urge you to carve out two hours (in most markets between 8pm - 10pm) on Wednesday night to watch it. The program is packed with science, history, and beautiful photography.

I've seen the film in advance, and I highly recommend it, particularly if you're interested in any of the four plants featured in it: tulip, marijuana, potato, and apple. By telling the stories of these plants, Pollan explains how in some ways the plants are manipulating us, rather than the other way around -- in the same way that flowers "use" bees to spread their pollen, these plants have "used" humans to spread themselves across the planet and out-compete other plants. One note: the program may not be suitable for young children, as there is use of the word "sex" (as applied to plants) and discussion of marijuana. It also might be pretty boring for the under-twelve set (despite beautiful flower photography), unless they're thoroughly nerdy.

Here's a preview of the documentary:

After the jump, I include some notes on each plant discussed in the documentary.

The Apple - Good for Booze AND for Eatin'

Apples arose in Kazakhstan, where bears would eat them and, uh, deposit the seeds as they went. But when people entered the picture, we began to spread the apple and its sweetness. Thus, the "biological strategy" of apples is to increase their sweetness, causing us to spread them around the globe. Humans have an innate desire for sweetness -- presumably because in nature, sweetness is rare and generally denotes lots of calories.

Although the Bible doesn't specify the fruit that was at the heart of so much trouble in the Garden of Eden, we assume it to be an apple -- even though it was probably a pomegranate due to geographic restrictions on where apples grow best. Then there's the rather fascinating discussion of Johnny Appleseed, whose real motivation was to bring alcohol (via hard cider) to pioneers, rather than tasty sweet apples. (Follow the link for some more info, all snagged from Pollan's book, on the man -- he was surprisingly rich for a dude who wore a tin pot on his head.)

Tulips

Tulips are examples of angiosperms, or flowering plants. The rise of the angiosperms brought sex (via flowers and pollen exchange) into the plant picture, and as Pollan says, "sex creates variation." The documentary thoroughly explains the Dutch speculative investment bubble known as Tulip Mania, which made tulips one of the most valuable commodities in the world. At the height of Tulip Mania, a single tulip bulb sold for the equivalent of what today would be $10-15 million! Tragically, some of the most prized tulips were made beautiful because of a virus that was slowing killing them -- which caused spectacular striped or "broken" flowers, but ultimately killed the plant. Pollan suggests that the tulip's biological "strategy" has been to develop a form of beauty that humans find very appealing, causing us to domesticate and grow it even to the point of financial ruin.

Cannabis

I won't say much about this section, as this is a family blog, but I can certainly say that this program treats the topic fairly and doesn't go nuts with it. There's an interesting discussion of how THC (the main "active ingredient") binds to receptors in the human brain that affect the brain's ability to remember and forget -- and Pollan wonders exactly how a plant would find a way to manipulate those human brain receptors in order to make cannabis such a widely-propagated plant today. It is a curious question, indeed -- how would a plant manage to just "happen" to have such a profound effect on humans? Again, Pollan wonders if this is a biological "strategy" in some sense.

The documentary includes extensive footage of legal (under state laws, though not federal law) cannabis growing operations -- you get an inside look into how medical marijuana is produced, and it's surprisingly complex. My favorite line: in describing how the farmers plant only female cannabis plants so they'll produce more THC-rich resin, Pollan describes the grow room as a room of "massive sexual frustration" -- all the female plants are desperately trying to catch some male pollen, producing more and more resin in their efforts.

Potatoes

The documentary takes us to South America, showing how the descendants of the Incas are still farming potatoes, and how potatoes traveled from South America to Europe via the Spanish Conquistadores. The potato was such a hugely productive crop (more food per acre than grain) that it transformed the Old World, enabling the industrial revolution. There's also much discussion of "The Lumper," the dominant strain of potato in Ireland that happened to be susceptible to a wind-spread fungus that destroyed Lumpers, causing the terrible Potato Famine. The famine killed one out of every eight people living in Ireland. Can you imagine that? Pollan suggests that the Potato Famine is a parable about the dangers of monoculture (planting a single type of plant) -- had the Irish planted a wider variety of potatoes, they might have had more that were resistant to the fungus that killed Lumpers.

Also discussed: how the fast food industry currently relies on a monoculture of the Russet Burbank potato to make the "long fries" used in McDonald's, to fill those tall red fry boxes; how that monoculture demands lots of pesticides; and how Monsanto is developing insect-repellant crops -- and what happens with those crops over the long term.

Full Blogger Disclosure

I have received an advance screener of this documentary from PBS, but have not been compensated in any way for this post. I just like PBS and documentaries, and think this is a great program -- and the book is highly recommended as well.

* = Note that the program is presented by KQED in San Francisco and produced by Kikim Media. But to myself and y'all, that's fancy talk for "PBS."

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Today's Wine Glasses Are Almost Seven Times Larger Than They Were in 1700
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Holiday party season (a.k.a. hangover season) is in full swing. While you likely have no one to blame but yourself for drinking that second (or third) pour at the office soiree, your glassware isn't doing you any favors—especially if you live in the UK. Vino vessels in England are nearly seven times larger today than they were in 1700, according to a new study spotted by Live Science. These findings were recently published in the English medical journal The BMJ.

Researchers at the University of Cambridge measured more than 400 wineglasses from the past three centuries to gauge whether glass size affects how much we drink. They dug deep into the history of parties past, perusing both the collections of the Ashmolean Museum of Art and Archaeology at the University of Oxford and the Royal Household's assemblage of glassware (a new set is commissioned for each monarch). They also scoured a vintage catalog, a modern department store, and eBay for examples.

After measuring these cups, researchers concluded that the average wineglass in 1700 held just 2.2 fluid ounces. For comparison's sake, that's the size of a double shot at a bar. Glasses today hold an average of 15.2 fluid ounces, even though a standard single serving size of wine is just 5 ounces.

BMJ infographic detailing increases in wine glass size from 1700 to 2017
BMJ Publishing group Ltd.

Advances in technology and manufacturing are partly to blame for this increase, as is the wine industry. Marketing campaigns promoted the beverage as it increasingly became more affordable and available for purchase, which in turn prompted aficionados to opt for larger pours. Perhaps not surprisingly, this bigger-is-better mindset was also compounded by American drinking habits: Extra-large wineglasses became popular in the U.S. in the 1990s, prompting overseas manufacturers to follow suit.

Wine consumption in both England and America has risen dramatically since the 1960s [PDF]. Cambridge researchers noted that their study doesn't necessarily prove that the rise of super-sized glassware has led to this increase. But their findings do fit a larger trend: previous studies have found that larger plate size can increase food consumption. This might be because they skew our sense of perception, making us think we're consuming less than we actually are. And in the case of wine, in particular, oversized glasses could also heighten our sensory enjoyment, as they might release more of the drink's aroma.

“We cannot infer that the increase in glass size and the rise in wine consumption in England are causally linked,” the study's authors wrote. “Nor can we infer that reducing glass size would cut drinking. Our observation of increasing size does, however, draw attention to wine glass size as an area to investigate further in the context of population health.”

[h/t Live Science]

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Researchers Pore Over the Physics Behind the Layered Latte
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The layered latte isn't the most widely known espresso drink on coffee-shop menus, but it is a scientific curiosity. Instead of a traditional latte, where steamed milk is poured into a shot (or several) of espresso, the layered latte is made by pouring the espresso into a glass of hot milk. The result is an Instagram-friendly drink that features a gradient of milky coffee colors from pure white on the bottom to dark brown on the top. The effect is odd enough that Princeton University researchers decided to explore the fluid dynamics that make it happen, as The New York Times reports.

In a new study in Nature Communications, Princeton engineering professor Howard Stone and his team explore just what creates the distinct horizontal layers pattern of layered latte. To find out, they injected warm, dyed water into a tank filled with warm salt water, mimicking the process of pouring low-density espresso into higher-density steamed milk.

Four different images of a latte forming layers over time
Xue et al., Nature Communications (2017)

According to the study, the layered look of the latte forms over the course of minutes, and can last for "tens of minutes, or even several hours" if the drink isn't stirred. When the espresso-like dyed water was injected into the salt brine, the downward jet of the dyed water floated up to the top of the tank, because the buoyant force of the low-density liquid encountering the higher-density brine forced it upward. The layers become more visible when the hot drink cools down.

The New York Times explains it succinctly:

When the liquids try to mix, layered patterns form as gradients in temperature cause a portion of the liquid to heat up, become lighter and rise, while another, denser portion sinks. This gives rise to convection cells that trap mixtures of similar densities within layers.

This structure can withstand gentle movement, such as a light stirring or sipping, and can stay stable for as long as a day or more. The layers don't disappear until the liquids cool down to room temperature.

But before you go trying to experiment with layering your own lattes, know that it can be trickier than the study—which refers to the process as "haphazardly pouring espresso into a glass of warm milk"—makes it sound. You may need to experiment several times with the speed and height of your pour and the ratio of espresso to milk before you get the look just right.

[h/t The New York Times]

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