The art of blending coffees from a variety of origins brought to approximately the same degree of roast is a subtler business, but hardly difficult once the basic principles are understood. Blenders who work for large commercial coffee companies need to be highly skilled because their goals are more complex than our simple efforts to blend a coffee that suits us better than would a single-origin coffee taken alone. The commercial blender blends to cut costs while maintaining something resembling quality, and wants to assemble a blend with consistent taste even though the single-origin coffees that make up the blend may differ. Certain coffees are not always available; some coffees may be cheaper than others at certain times of the year, and so on. But in an economy dominated by highly advertised brand names, the blend has to taste more or less the same every time. So blenders may find themselves amid a shifting kaleidoscope of prices and availabilities, constantly juggling coffees in an attempt to keep the taste the same and the cost down.
A good commercial blend may take an acidy, aromatic coffee such as a Colombia, Costa Rica, or Mexico and combines it with a decent grade of Brazil coffee to cut costs, plus some bland robustas to cut costs still more and add body. If it is a premium blend, the blender might combine more than one quality coffee with the Brazil: a rich, full-bodied coffee to balance a bright, acidy coffee, for instance. Low-cost blends might decrease the proportion of high-grown and Brazil coffees and make up the difference with robusta. The cheapest blends eliminate the high-grown coffee entirely and simply combine a decent grade of Brazil with the robustas.
With blends found in specialty-coffee stores, the blender’s main goal is to produce a distinctive and consistent coffee, rather than simply to cut costs. A typical specialty roaster may have only one blend, a house blend, or a dozen for all pocketbooks, tastes, brewing methods, and times of day. Some larger specialty roasters, like their commercial counterparts, also may blend for price, although (one hopes) with less urgency and compromise.