What/when/how do you consider coffee as organic? Our shop joined this bazaar and we we're selling roasted beans (Brazil Santos) which we get green then roast in our shop. A customer was asking questions about the coffee beans and the only one thing I wasn't able to answer thoroughly was: "Is this organic?"

What coffee is organic? or should I say: How or when do we consider a certain coffee to be organic?
You were most likely right in saying 'no' straight out.

Coffee is considered organic if no chemical substances were used for its production. This includes herbicides, pesticides, and I believe some fertilizers too. Wikipedia agrees with this.

But even if you're a coffee producer and you're sure you don't use chemical substances and there are no residues in the soil, that's not enough. You have to certify your product and you'll be able to say that your coffee is certified organic. The certification process and agency will depend on where the coffee is grown.

Of course, the certification costs. And some producers might not afford it (thanks to Chris_in_AK for pointing this out).

Since you're only roasting the beans and not producing them, it's not really up to you (you could ask your provider if the beans they're selling you are certified organic). But you could buy beans that are certified organic.