The Science Behind A Stronger Pour-over With Less Beans – CoffeeTalk

Researchers have discovered a way to make a stronger pour-over coffee without the need for expensive beans or filters. Dr Arnold Mathijssen, a co-author of the study from the University of Pennsylvania, found that pouring hot water slowly from a goose-neck kettle increases contact time between the water and the coffee grounds, while pouring from a greater height increases mixing, both of which result in more coffee being extracted. However, he also warned that if you pour too slowly or go too high, the jet tends to break up into smaller droplets, which is what you want to avoid.

The team carried out experiments involving transparent silica gel particles representing ground coffee, which were illuminated with a laser sheet and recorded with a high-speed camera. While slow pouring increases contact time, the velocity of the water was too low at low heights to dig into and disturb the bed of particles. Water poured from greater heights resulted in greater agitation of the particles, but the team found that water must flow in an unbroken jet to dig into the bed of particles and displace those at the bottom of the funnel, resulting in particles building up on the sides and then falling in, creating an avalanche-like effect that increases mixing.

When applying their findings to coffee itself, the team found that pouring from a greater height resulted in stronger brews, provided an unbroken flow of water was used. A good starting point for those at home is to reduce the amount of ground coffee by 10%, say from 20 to 18 grams per cup, and taste the coffee produced by pouring the hot water at different heights, keeping a limit of about 30cm for safety.

Read More @ The Guardian