I added Guatemala Robusta beans to my Colombian. When asking my coffee pusher about the negativity towards Robusta as being inferior, he pointed out to me that some of the finest Italian espressos are indeed Robusta, or Robusta blends, and that there is such a thing as well grown and processed Robusta.
As someone who is not a coffee snob, or could care less about all of the subtle, sensory surprises, and that prefers sweetener/cream in coffee, fresh roasted Arabica can be a bit *too* smooth, or mellow. Adding the Robusta at a ratio of about 30%, put back some of that smoky, sour edge that I get from shelf brands. This, after giving about 10 different Arabicas a try.
Also tried the Aeropress. While it makes a good cup of coffee, it still doesn't win out over the drip machine. Must be the timing vs. grind, or whatever. I notice how there is a buildup of hot water in the basket before the filter can let it out fast enough, so all of the coffee is being steeped for roughly 10 mins.
Current blend is, 70% Colombian (Sierra Nevada FTO) roasted to right at the beginning of second crack and 30% Guatemala Robusto, with half at beginning of second crack, and half at full second (dark and oily) crack.