Cold Brew Coffee Extraction: Time, Temperature, and Grind Size

Volume I  ·  May 2026  ·  436 words

Cold brew extraction operates on fundamentally different kinetics than hot brewing. At refrigerator temperature (4°C), the rate of dissolution for coffee solubles is approximately 4–5× slower than at 93°C, which is why cold brew recipes specify 12–24 hour steep times rather than the 3–5 minutes of hot pour-over. But extraction is not simply slowed — it is also selective. Different compound classes dissolve at different rates relative to each other at low temperature, producing a flavor profile that is chemically distinct from the same coffee brewed hot and then chilled.

The primary selectivity is between organic acids (citric, malic, chlorogenic) and the bitter-tasting compounds produced during roasting (Maillard reaction products, caramelized sugars). At low temperature, acid extraction is more suppressed than bitter-compound extraction. The result is a cup with lower perceived acidity — often described as "smooth" or "mellow" — not because fewer total compounds are extracted, but because the ratio of bitter to acidic compounds is shifted. A 2018 study in Scientific Reports measured extraction yields of 14–18% for 24-hour cold brew versus 18–22% for hot brew, with the missing fraction consisting primarily of the more polar, water-soluble compounds that require thermal energy to dissolve efficiently. This is why cold brew tastes fundamentally different from iced hot coffee — it is chemically different, not just colder.

Grind size for cold brew is coarser than for pour-over (typically 800–1,200 microns, similar to French press) because the extended contact time compensates for the reduced surface area. Fine grinding increases extraction yield but also increases sediment and turbidity in the final cup. The Takeya cold brew maker and Toddy cold brew system are the two dominant consumer formats — the Takeya uses a fine-mesh infuser insert for easy cleanup, while the Toddy uses a felt filter pad that produces a cleaner cup at the cost of more involved filter maintenance. Concentrate-to-dilution ratios vary from 1:1 (strong) to 1:3 (standard), with the concentrate stable in refrigeration for 7–10 days.