eli5 How exactly does one “de-caffeinate” coffee? Are they actually removing the chemical?
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Yep! One process is to soak and drain it with liquid carbon dioxide (under high pressures, carbon dioxide can be a liquid), which carries most of the caffeine away, while leaving almost all the rest of the coffee-stuff behind.
Note that decaf coffee contains *less* caffeine, not *no* caffeine. It can still keep you awake at night if you’re not accustomed to it.
Yes. Decaffeination is usually done before the coffee beans are treated in any way. They use a variety of chemicals to literally wash out the caffeine from the coffee beans, then they just treat the beans as they normally would. Brew the resulting ground and you have coffee without caffeine. The very first method involved steaming the raw coffee beans with an acid, then washing them with benzene. The benzene dissolved the caffeine and carried it away.
They de-caffeinate coffee based on the solubility of caffeine in different solvents. Since caffeine is very soluble in some organic solvents such as ethyl acetate. You can isolate the caffeine from the beans using this solvent.
‘Selective’ solvents- unlike water, the ‘universal solvent’ due to its bipolarity- take a subset of molecules which may be otherwise dissolved into broader acting solvents.
The most popular method, the Swiss water method, works by essentially extracting all the flavor out of some coffee with water and removing the caffeine from it.
Now that you have a bunch of caffeine free, coffee flavored water, you dry and submerge new beans in that solution. Since stuff like caffeine wants to be evenly distributed, it’ll leave the beans which are full of caffeine and enter the water which has no caffeine.
If you didn’t make the coffee flavored water, that coffee flavor also would’ve left the beans but thankfully the water solution helps keep it intact.
Now that some caffeine is in the water, the water has its caffeine removed and reinserted back into the mix and we’re back to step one. Over time, they’ll do this until nearly all the caffeine in the beans are gone.
Once upon a time a famous brand of decaffeinated removed the caffeine with ethylene chloride. A report came out that ethylene chloride was mildly carcinogenic so they switched to methylene chloride instead. Turned out the methylene chloride was much worse than the ethylene chloride.
The best method is EA or ethylene acetate that is derived from sugar cane. When the beans are submerged, it extracts only the caffeine and leaves the flavor compounds in tact, unlike the swiss water method. EA decaf is more expensive since EA is a controlled substance as it is widely used in cocaine production
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