There was a time when we didn't talk about decaffeinated coffee. Why bother? Everybody knew that decaf was not to be taken seriously and, if used at all, was to be hidden away in a dark place along with soymilk substitutes and vacuum-packed nut cutlets. But not now. Decaf is out of the closet and making up for all those years in the wilderness.

The editor turns eagerly to Matthew Algie's scientist-in-chief, Ewan Reid, to make sense of it all. It's to do with some water, apparently.

"We use Swiss Water Decaffeination. Removing caffeine from coffee beans is nothing new, and there are a number of techniques. The Swiss Water process is an expensive one but it results in the best coffee taste" explains Ewan, putting down his test tubes for a moment. But how does it all work?

Ewan goes into technical mode. "Arabica coffee beans are circulated in flavour-charged water. This is water saturated with coffee flavour components. Flavour-charged water circulation is unique to the Swiss Water process and prevents most of the flavour compounds within the beans from dissolving during decaffeination, whilst at the same time the caffeine from the beans is absorbed into the surrounding liquid."

So far, so wet. "We then use a series of activated carbon filters to remove all the caffeine from the flavour-charged water, and it can be used again for the next batch of beans. It's a remarkably efficient process, and an expensive one, not least because of the strict caffeine monitoring involved." So, how are other coffees decaffeinated, then? "Typically, coffee is decaffeinated through a variety of more chemically-reliant, severe processes involving substances like Methylene Chloride, Supercritical Carbon Dioxide or Ethyl Acetate. In fact, Ethyl Acetate is a natural substance found in fruit but, like the other chemical processes, it can leave a distinctive aftertaste that most coffee drinkers can detect."

Thanks for the Ewan. Now, for those of us without a scientific mind, there is a simpler version! The Swiss Water process uses water - no nasty chemicals - to remove the caffeine, but not the flavour. Matthew Algie now has a fine example of Swiss Water decaffeinated beans: our scrumptious new Sumatra Mandheling Decaf. In a shocking departure from the horribly bland decafs of old, these beans yield an amazing flavour. And, of course, you can drink it at bedtime. If you like that sort of thing.

1. Caffeine removal Caffeine moves from green coffee beans to water.

2. Water Recycled Water drains out to be reused after being carbon flitered, leaving decaffeinated coffee beans.

3. Carbon Filter Removal of caffeine from flavour charged water.

This article originally appeared in Fresh 10