Coffee needs 24-36 hours to de-gas after roasting. More than that becomes detrimental. Of course, the stuff at the grocery store in cans is generally MONTHS post-roasting, so even week old coffee is an improvement. Sweet Marias is a good place to do business. I have probably had well over 100 varietals in the past 5 -7 years, and here is my advice.
First, find a bean you like, and understand it will change with each crop, and even a tiny bit with each batch roasted. Then try to find a supplier who will ship the same day as roasting (bags have a one-way valve to allow de-gassing), who is no more than 3 days shipping from you, and never ship when the beans might sit in a hot truck (I tend not to order about May-September). You will find connoseuirs who will insist on roasting green beans daily, and that freezing is intolerable. I have pretty discriminating taste buds, and I freeze roasted beans, grinding almost daily what I need. I have talked with others who I think are just as particular about their coffee, and most agree with me that freezing the roasted bean works very well.
I have three basic beans I use, and blend in different proportions depending on what I want....2-3 more types of beans I buy from time to time for variety. I have never found a single bean that I enjoy as much as I do the blends I can make. Most great espresso is made from blended beans....some beans have better aroma, some finish better, some make a better initial presentation.
I order Blue Mountain from a grower in Kauai (
Kauai Coffee Company) ....I find it infinitely smoother than the Blue Mountain from Jamaica, but it has a very bold full finish. It is roasted on a Friday in most cases, and shipped air, arriving on Monday. I order Kona extra fancy from a supplier on Maui (superbeans.com), and I order Guatamelan organic (fantastic dark chocolate overtones) from Coffee Break Roasters in Cincinnati (
http://www.coffeebreakroasting.com/). I also get a columbian bean (viennese roast) from Coffee Break Roasters, and a couple others. They ship UPS the day of roasting in the valved bag. Look for a local roaster....fresher is better. Many of the large suppliers will ship stuff roasted days ago...I believe Sweet Marias is an exception to that.
Start slowly, so you can process over time what you really enjoy the most. The variations and variables are nearly endless. Coffee is an excellent source of antioxidants (yes, it's good for you!) and the number of flavonoids (the little things that create flavors) in coffee far exceeds those in wine......i.e., there are more possibilities for flavors in coffee than virtually anything else we ingest. Feel free to email for any information, and enjoy the journey. Coffee is one of my favorite things, and it is a true pleasure for me each day.