The small but mighty sprayhead is the unheralded work horse for most BUNN coffeemakers. The average coffee drinker probably is unaware of the importance of this component and its function in a quality brewer. It is the critical delivery vehicle that controls how the water gets dispersed, or "broadcast," over the coffee with the ultimate goal being uniform flavor extraction from a bed of grounds.

BUNN’s unique sprayhead designs create the right amount of turbulence to cause the grounds to rise and suspend in the hot water solution in order to extract flavor evenly and thoroughly from all of the grounds. Without a proper sprayhead design, water drips straight through and often does not expose coffee evenly. This will result in very erratic levels of extraction, often all in the same pot of coffee.

The flow rate of the sprayhead needs to deliver the water to the coffee in a time frame that will work with the grind size. Also known as the "Wetting Phase" of the three-phase brewing process, this initial step is when the grounds begin to absorb the hot water from the sprayhead and release gasses from the coffee. For consistent extraction from all parts of the coffee grounds, the entire bed of coffee must be wetted in the first 10% of the brew cycle. For finely ground coffee, the ideal brew time-or the time the water hits the grounds and filters through-is four minutes or less. A longer brew time is required for the water to penetrate larger grind particles. An operator should experiment with a coarser or finer grind to attain the preferred flavor profile.

The second factor that works in tandem with the function of the sprayhead is placing an ideal bed depth of 2.5-5.0 cm (1-2 inches) of grounds in the brew basket. If the coffee bed is less than 2.5 cm (1 inch), the force of the sprayhead may cause the water to move through too quickly and under-extract the flavor from the coffee grounds. Likewise, water moving too slowly through the grounds may cause an over-extraction of flavor and a bitter taste. Less experienced coffee drinkers often mistake bitter coffee for coffee that they describe as "too strong." The real culprit, however, is often an inappropriate pairing of sprayhead design and the amount of coffee grounds placed in the brew basket.

There have been a myriad of sprayhead designs with various patterns and hole sizes over the years. BUNN currently has various sprayhead designs to accommodate the function of the brewer and funnel size. For most low- to medium-volume brewers, a six-hole pattern achieves the ideal water broadcast and contact time in the brew funnel with the ground coffee. Some brewer designs may also feature a pulsating broadcast in order to achieve the ultimate uniform extraction. A chief reason the sprayhead is replaced with an alternate design would be to alter the flow rate into the funnel. The five-hole design has a narrower pattern and a slower rate than the six-hole design. Some operators may need a slower flow rate to compensate for softened water or to accommodate a different width size of the funnel.