Note sull'episodio
Decaf's story starts with Goethe, who handed chemist Friedlieb Ferdinand Runge a carton of rare Arabian coffee beans, which Runge used to isolate caffeine for the first time. The commercial breakthrough came from an accident in 1903, when German merchant Ludwig Roselius found that a seawater soaked shipment had lost its caffeine but kept its flavor. He patented a process in 1906 that steamed beans and washed them with benzene, now known as a potent carcinogen, and sold the result as Café HAG in Europe and Sanka in the US and France.
Safer methods followed. Direct methods rinse steamed green beans 8 to 12 times with dichloromethane or ethyl acetate. The indirect method, described by 1941, soaks beans in water, strips caffeine from that water, and reuses the flavor saturated liquid so only caffeine migrates out of fresh beans. The Swiss Water process runs the same idea through activated carbon for 8 to 10 hours, the triglyceride process uses oils from spent grounds, and Kurt Zosel of the Max Planck Institute developed supercritical carbon dioxide at 65 degrees Celsius and 300 atmospheres. Even so, decaf is rarely zero caffeine, and a caffeine free coffee plant found in 2004 is not yet on the market.
- The US requires 97 percent of caffeine removed, the EU 99.9 percent caffeine free by mass, and Canada under 0.1 percent residual.
- Labs check levels with HPLC and with UV-visible light, since caffeine absorbs near 273 nanometers.
- A 2006 Florida State University study found 8.6 to 13.9 mg of caffeine in a 16 ounce coffee shop decaf.
- Steeping tea at 100 degrees Celsius for three minutes removes 83 percent of its caffeine while keeping 95 percent of catechins, but the 30 second home rinse trick fails.
- Coffea charrieriana, discovered in 2004, has a faulty caffeine synthase gene and stockpiles theobromine instead.