Based on some light reading just now:

- SWP is a means of treating green coffee beans pre-roast. They can be roasted any which way afterwards.

- Any type of bean can be treated this way.

- The process is pretty specific in targeting just caffeine. In removing caffeine though, the total dissolved solubles in the end coffee will be lower for the same amount of beans. Probably a lessor body unless you use more.

Interested to hear from someone who has tried it.

I roast my own coffee beans. I usually get decaf SWP beans from Sweet Marias. https://www.sweetmarias.com/green-coffee/decaf.html The decaf SWP beans start out a different color of green bordering on tan compared to the light green of regular "green" coffee beans. Its not just the starting color, they roast differently too. Coffee beans crack during roasting - there is a first crack and then if you want it dark there is a second crack. The sound is usually pronounced. With the SWP beans the crack sound is more of a poof. Apparently SWP changes the structure of the beans, possibly introducing cracks or holes. The roasted beans seem drier and duller brown in color, less mahogany, less shiny. Its hard to know what the flavor impact of SWP was b/c I haven't tried the same beans before they were made decaf. It could just be my own prejudice or lack of skill in roasting but I would say on average the decaf coffee turns out 5-10% worse in quality.

In practice, it's far easier to find good single-origin roasts than to find good decaf options. I've actually never been able to find anything lighter than medium roast in SWP -- not sure if that's for some functional or taste reason, or just because it's a sliver of a sliver of the market.

I am very sensitive to caffeine and recently switched to decaf only after drinking coffee daily for 20+ years. I drink mainly Mountain Water Processed coffee, which is the same thing but from coffee sourced in South America. It is roasted by a local roaster in Minneapolis. I honestly can't tell the difference between the decaf and regular (except for the lack of caffeine).

Also, SWP or MWP coffee removes nearly all caffeine unlike the more heavily processed versions.

Which Minneapolis roaster? I'm local

UP Coffee Roasters / UP Cafe