Most people probably wouldn't notice the difference - the overall taste of the espresso is a result of many influences which include the growth, harvest & roasting of the beans. Organic farming of the beans will have an impact on the taste although this particular influence would be difficult for most of us to pick up. Taste a couple and see if you notice a difference - although you're trying to pick up something, your taste buds might get creative! As fas as I know, in NZ anyhow, if the beans are certified to be organic this refers to the entire process & production to that point - including roasting. If the beans were farmed organically but not in the roasting process, they can't be advertised as organic.

One of my favourite cafes near where i live serve an organic blend & i think they make the best latte in town. I don't think it's necessarily the organic part that makes it taste so good but the fact that the coffee IS organic has got to influence the taste somehow. I know when I buy organic fruit & veges THEY seem to taste better but maybe it's a preconceived expectation that if is organic it WILL taste better? Mind over matter maybe? Try it yourself - a good excuse for another cup I reakon! I'll be taking note next time i'm out!

I'd say the best way to find an answer would be try it yourself! Sample a couple of organic brews & a couple of non organic - maybe not back to back! You could always ask the folk at your local coffee shop, they might have an opinion on the blend that they serve.