Curious about the need to grind decaf so much finer than regular beans

My guess - and it’s a wildly uninformed guess - is that decaffeination removes “other” easily water-soluble compounds in addition to caffeine that would typically form fines in non-decaffeinated coffee. These ‘clog’ the puck (especially in the initial phases of extraction) enough that it doesn’t gush even if the average particle is larger, but aren’t there in decaffeinated grounds.

Here is a daft question. Can you decaffeinate any bean, and if so, why is there relatively little choice

thusband Yes, interesting thread. I wish there was a wider selection of decaf green beans. I’d like to try that sugarcane process.

Sugarcane decaffeination utilizes a naturally occurring compound, ethyl acetate (EA) to decaffeinate coffee. The EA used in this process is derived from molasses (a by-product of sugar production). Since  EA is naturally-occurring, the process is labelled as “naturally decaffeinated.” 

The EA process is relatively simple. The coffee beans are moistened with water and EA is circulated throughout. The EA binds with the caffeine in the bean and extracts the caffeine while leaving most of the other flavour compounds. After the desired caffeine level is reached, the EA residue on the beans is removed by steaming them. 

DavecUK Ethyl acetate isn’t actually naturally occurring, rather it is synthesised from sugarcane. You take the sugar from sugarcane, ferment it into ethanol, and then oxidise the ethanol with acid to form ethyl acetate.

For the grind size, as well as opening the pores more (which is why decaf beans after being roasted look oilier), it makes the bean more brittle. I think it’s this change in how brittle it is that impacts the required grind size.