How Do You Decaffeinate Coffee Beans?

iStock / RyanJLane
iStock / RyanJLane

There are a number of ways to cut the eye-opening power of a cup of joe, but the methods are basically pretty similar. First, processors use water or steam to swell the green beans, then they extract the caffeine using a solvent. Water, ethyl acetate, methylene chloride, or highly pressurized carbon dioxide strip the caffeine away from the beans, which are then steamed to remove any solvent residues and dried.

Do these methods get all the caffeine out?

Not quite, but it strips away quite a bit. According to U.S. law, any decaffeinated coffee must retain less than 2.5% of its caffeine, while in the EU only 0.1% of decaf beans’ dry weight can be caffeine. According to the International Coffee Organization, a cup of decaf has around 3 mg of caffeine in it, while the average 5 oz. cup of drip coffee contains 115 mg.

What happens to all the caffeine that gets stripped from the coffee?

It would be a shame for all that caffeine to go to waste—there are undercaffeinated children in third-world countries, you know—so processors save and sell the jittery gold. Pharmaceutical companies and soft drink makers are the big customers for the extracts; although the kola nut provides a bit of a jolt for your cola, the majority of the caffeine in your soda comes from the addition of caffeine extracted from coffee beans during decaffeination.

This post originally appeared in 2010.

Why Are Sloths So Slow?

Sloths have little problem holding still for nature photographers.
Sloths have little problem holding still for nature photographers.
Geoview/iStock via Getty Images

When it comes to physical activity, few animals have as maligned a reputation as the sloth. The six sloth species, which call Brazil and Panama home, move with no urgency, having seemingly adapted to an existence that allows for a life lived in slow motion. But what makes sloths so sedate? And what horrible, poop-related price must they pay in order to maintain life in the slow lane?

According to HowStuffWorks, the sloth’s limited movements are primarily the result of their diet. Residing mainly in the canopy vines of Central and South American forests, sloths dine out on leaves, fruits, and buds. With virtually no fat or protein, sloths conserve energy by taking a leisurely approach to life. On average, a sloth will climb or travel roughly 125 feet per day. On land, it takes them roughly one minute to move just one foot.

A sloth’s digestive system matches their locomotion. After munching leaves using their lips—they have no incisors—it can take up to a month for their meals to be fully digested. And a sloth's metabolic rate is 40 to 45 percent slower than most mammals' to help compensate for their low caloric intake. With so little fuel to burn, a sloth makes the most of it.

Deliberate movement shouldn’t be confused for weakness, however. Sloths can hang from branches for hours, showing off some impressive stamina. And because they spend most of their time high up in trees, they have no need for rapid movement to evade predators.

There is, however, one major downside to the sloth's leisurely lifestyle. Owing to their meager diet, they typically only have to poop once per week. Like going in a public bathroom, this can be a stressful event, as it means going to the ground and risking detection by predators—which puts their lives on the line. Worse, that slow bowel motility means they’re trying to push out nearly one-third of their body weight in feces at a time. It's something to consider the next time you feel envious of their chill lifestyle.

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Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

This post originally appeared on Quora. Click here to view.

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