Cold brew is made by steeping extra-coarse coffee grounds in cold filtered water at a 1:8 ratio for 16 to 18 hours. The cold water extracts sweet carbohydrates and cacao solubles while leaving bitter chlorogenic acids behind, resulting in 67% lower perceived acidity than hot-brewed coffee.
Why Cold Water Changes Coffee Chemistry
Hot water is an aggressive solvent. Temperatures around 200°F rapidly dissolve acidic compounds like quinic and chlorogenic acids. In cold water, those acids dissolve extremely slowly. Instead, extended 18-hour contact time dissolves only the sweet caramel and chocolate compounds, resulting in smooth, syrupy coffee that is naturally gentle on sensitive stomachs.
Concentrate vs. Ready-to-Drink
Brewing a concentrate (1:8 ratio) has three major advantages:
- Takes up half the space in your refrigerator.
- Stays fresh and stable for up to 14 days without going stale.
- Allows you to customize each glass: dilute 1:1 with ice water for an iced Americano, or 1:1 with whole milk / oat milk for an iced cold brew latte.
Always double-strain! Use a metal sieve to catch the heavy coarse grounds, followed by a paper filter pass. The paper filter captures microscopic fines, turning a cloudy brew into crystal-clear cold brew nectar.