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

thusband

I roast my own beans. Decaf for the wife and regular for me. I grind for espresso and the setting in my Niche for decaf is around two but for my non-decaf it’s 12.

If I pull a shot of decaf at the grind setting for non-decaf it gushes out of the portafilter. Why does decaf require a much finer grind?

DavecUK

thusband I expect it’s a result of the decaffeination process.

thusband

Right. Something must happen to the bean structure during the process that changes things. I wonder what that is?

DavecUK

thusband Probably the boiling with water, or steaming process to open the bean structure for removal of CO2

thusband

DavecUK

So the beans are actually "cooked’ a bit during the process? I know decaf green beans are generally darker than regular beans.

CoyoteOldMan

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.

Just So Stories

thusband

CoyoteOldMan

That sounds reasonable to me. If fines are removed it would certainly explain the gushing.

dfk41

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

LMSC

dfk41 Can you decaffeinate any bean, and if so, why is there relatively little choice

There was a good discussion about this recently.

Please read this

https://coffeetime.freeflarum.com/d/760-sugarcane-or-swiss-water-decaf/26

thusband

LMSC

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

DavecUK

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.

thusband

DavecUK

Very interesting. Do you know of any sugarcane decaf suppliers of green beans in the UK?

hornbyben

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.

DavecUK

thusband Not really, I suspect roasters will from time to time get sugar cane decaf in…because it’s good marketing as it sounds good.

This search shows up quite a few: https://www.google.com/search?q=sugfarcane+decaf+uk&rlz=1C1CHBF_en-GBGB858GB858&oq=sugfarcane+decaf+uk&aqs=chrome..69i57j0i546l4.7849j0j15&sourceid=chrome&ie=UTF-8

thusband

DavecUK

Yes, I’ve Googled around but nobody, so far, has any greens.

thusband

hornbyben

Interesting. Thanks!