Yellow Bourbon is a Bourbon mutation whose cherries ripen to yellow instead of red, found in Brazil in the early twentieth century.
The sweetness
Widely regarded as Brazil’s sweetest variety, with a rounded, low-acid, honeyed character. Mogiana and Mantiqueira Yellow Bourbon in particular can be genuinely delicate.
The picking problem
Ripeness is judged visually, and a yellow cherry going from underripe to overripe is much harder to read than a green cherry turning red.
That costs precision at harvest, and it is why some producers avoid it despite the cup.
Where it grows
Brazil principally, with plantings in Central America.
Brewing it
Filter at light to medium roast, or espresso where the sweetness carries through milk.
How producers handle the picking problem
Brazilian farms that specialize in it pick in several passes, or harvest by machine and then sort by density and with optical sorters, which can separate underripe fruit that the eye would miss. Many also dry it as a natural or pulped natural, processes that add sweetness. A bag saying Yellow Bourbon from a named Brazilian fazenda usually signals care, though the variety alone guarantees little: treat it as you would any Brazilian coffee, grind medium, and expect caramel, milk chocolate and honey rather than fruit.