The high heat and fast brew times of hot brew coffee makers create bitter coffee that's high in acid and hard on the stomach. The patented Hourglass cold-brew coffee maker solves this problem, producing a coffee extract with 69.9% less acid than hot brewed coffee in certified lab tests. The result is a smooth, rich tasting coffee that's healthier than hot brew and easy on the stomach. The coffee extract stays fresh in the fridge for 2 weeks. Just add hot water for a fast, convenient cup anytime.