Many roasting companies treat their blends as trade secrets - no different from consumers not knowing the recipe for Coca-Cola. Nothing shady about it.

It definitely is. I wonder if there are other people who are affected by this. I can absolutely understand that it won't matter to most tho.

Quite a few of the large Italian roasters post their Arabica/Robusta ratios: here's Manaresi's

What you seem to care about the most is caffeine content and I've never seen any roaster specify that. Robusta percentage doesn't tell you with any certainty.

coffee_maybe wrote:Decided to drop them a mail and they replied "due to a policy of the company we cannot indicate the exact percentage of Arabica and Robusta in our products".

FYI, as a site policy documented in the Guidelines for productive online discussion, we do not allow verbatim quoting of emails without the permission of both parties. I've edited your post accordingly and left the key salient point.

coffee_maybe wrote:Do you find this practice a little shady? Personally I find that this is something that can stop me from buying a certain bean if I can't find that information. Taste is king but I really don't want to buy a 1kg bag that ends up being 50/50 arabica and robusta for example.

Am I being too picky?

How picky you want to be is entirely up to you, but don't feel that this is the only practice that you might regard as "shady". For example, blends are often the dumping ground for green buying mistakes, or places where roasters are very price sensitive and buy cheap stuff - coffee might be past crop (like a year or two older than the current crop), or it might have good aspects offset by a number of bad aspects. This is particularly the case with "espresso" blends, where the darker roast level introduces bitterness to the cup, so roasters often seem to feel that if the coffee they are putting into the blend is astringent, papery, phenolic, medicinal, rubbery or has a host of other bad aspects, they're going to be hidden in the roast level anyway. There's coffee around on the market that has so many defects to it that it is not specialty grade. Like it's not all that uncommon that I'll taste commercial blends that seem to have mould or phenolic defect.

If a roaster doesn't want to disclose the composition of the blend, it may be that they need a bit of flexibility. This might be because they are buying different components specially for the blend, or it might be because the blend is a dumping ground for leftovers that they wind up with. And if they a roaster has coffee that isn't too characterful, in fairness, they can probably hide 10-15% in a blend without most people realizing.

Then there's the whole mire around coffee companies' representations around sustainability and what they pay for their green coffee, where, suffice to say, most coffee companies will make some noises about paying some amount that they think is fair, and most of them will not provide actual details to consumers.

The flipside is that invariably many consumers have a pigheaded combination of wanting to pay very little, and wanting to believe some sort of marketing puffery along the lines that they are getting "only the finest."

So ... are you being too picky? It's caveat emptor.

(I say all of this as general comments - I don't know anything about this particular roaster.)

Back to the challenge of the OP seeking a lower caffeine Pellini coffee, Pellini Top is that roaster's 100% Arabica blend. I tried it a few years ago and found it very mild and chocolaty. Some other Italian roasters feature all arabica coffees and generally charge a bit more for them.