Cold brew coffee is coffee made by steeping coarsely ground coffee in cold or room-temperature water for 12–24 hours, then straining out the grounds. No heat is used at any point. The result is a smooth, low-acid coffee concentrate that is typically diluted before drinking.
Cold brew is not iced coffee (which is hot-brewed coffee poured over ice). The cold-water extraction process produces a chemically different beverage with a distinctly smoother, sweeter, and less bitter taste.
How Cold Brew Is Made
The process is simple but slow:
- Combine coarse-ground coffee with cold or room-temperature water — typically at a 1:4 to 1:8 ratio of coffee to water depending on whether you want concentrate or ready-to-drink strength.
- Steep for 12–24 hours — most recipes call for 16–18 hours in the refrigerator, or 12 hours at room temperature.
- Strain out the grounds — through a fine-mesh strainer, cheesecloth, or a dedicated cold brew maker.
- Dilute if needed — concentrate is typically diluted 1:1 or 1:2 with water or milk before serving.
The full cold brew ratio guide (with tables for concentrate vs. ready-to-drink strengths) is at Cold Brew Ratio: How to Get the Perfect Strength.
Why Cold Brew Tastes Different From Hot Coffee
Temperature fundamentally changes how coffee extracts. Cold water:
- Extracts fewer bitter compounds — Chlorogenic acids and quinic acids (the sour, bitter molecules) require heat to extract efficiently. Cold water leaves most of them behind.
- Extracts more slowly and selectively — Time replaces heat. Only the soluble sugars, oils, and caffeine extract fully in cold water, producing a sweeter, rounder cup.
- Produces a lower-acid beverage — Cold brew is typically 60–70% less acidic than hot-brewed coffee, measured by pH. This makes it easier on the stomach for acid-sensitive drinkers.
- Results in a more shelf-stable product — Without heat-triggered oxidation, cold brew concentrate keeps in the refrigerator for up to 2 weeks. Hot coffee goes stale within hours.
| Factor | Cold Brew | Hot Coffee |
|---|---|---|
| Acidity | Low (pH ~6.3) | Higher (pH ~5.1) |
| Bitterness | Low | Medium–High |
| Sweetness | Naturally sweet | Less apparent |
| Caffeine | Higher per oz (concentrate) | Standard |
| Shelf life | Up to 2 weeks | Hours |
| Brew time | 12–24 hours | 2–5 minutes |
Types of Cold Brew
Cold Brew Concentrate
The most common home preparation. Brewed at a 1:4 ratio (1 cup coffee to 4 cups water), then diluted before drinking. Concentrate is versatile — mix with water, milk, oat milk, or use as a base for cocktails and coffee drinks.
Ready-to-Drink Cold Brew
Brewed at a 1:8 ratio, drinkable straight from the fridge. Takes the same time to make but produces a lighter result. Good for batch brewing a week’s supply.
Nitro Cold Brew
Cold brew infused with nitrogen gas, typically served from a pressurized tap. The nitrogen creates a creamy, cascading head similar to a nitro stout beer. Nitro cold brew tastes creamier and slightly sweeter than regular cold brew due to the nitrogen gas suppressing bitter flavor perception — and because no additional ingredients are added, it remains dairy-free and sugar-free.
Starbucks popularized nitro cold brew commercially in 2016. Home nitro setups (countertop nitro systems) exist but are a significant investment. Most home baristas drink their cold brew over ice with milk or as a base for other drinks.
Flash Brew (Japanese Iced Coffee)
A hot-then-cold method sometimes confused with cold brew: coffee is brewed hot at double-strength directly onto ice, which instantly chills it. Flash brew has the brightness and acidity of hot coffee but is served cold. Very different from cold brew’s smooth, low-acid profile.
Cold Brew vs. Iced Coffee
| Cold Brew | Iced Coffee | |
|---|---|---|
| Brewing method | Cold steep 12–24 hrs | Hot-brewed, poured over ice |
| Taste | Smooth, sweet, low acid | Brighter, more bitter, can taste watered-down |
| Acidity | Low | Higher |
| Caffeine | Higher (concentrated) | Standard |
| Prep time | 12–24 hours ahead | 5 minutes |
| Cost | Cheaper per serving | Similar or cheaper |
For the full side-by-side breakdown, see Cold Brew vs. Iced Coffee: The Complete Comparison.
How to Make Cold Brew at Home
You do not need special equipment — a mason jar, a strainer, and coarsely ground coffee are enough.
Basic method (makes ~4 servings concentrate):
- Add 1 cup (90g) coarsely ground coffee to a 32oz mason jar
- Pour in 4 cups (950ml) cold filtered water
- Stir gently to saturate all grounds
- Cover and refrigerate for 16–18 hours
- Strain through a cheesecloth-lined strainer into another jar
- Dilute 1:1 with water or milk to serve over ice
For a complete recipe with timing variations, ratios table, and equipment options, see Cold Brew Coffee Recipe: How to Make Cold Brew at Home.
Frequently Asked Questions
Is cold brew stronger than regular coffee?
Cold brew concentrate is significantly stronger than drip coffee — typically 2–3× the caffeine concentration. However, cold brew is almost always diluted before drinking, which brings the final caffeine content close to (or slightly above) regular drip coffee. Starbucks Grande Cold Brew contains approximately 205mg of caffeine vs. ~165mg in a Grande drip coffee. The concentrate itself, undiluted, is very high in caffeine.
Is cold brew good for GERD?
Cold brew is one of the most GERD-friendly coffee options due to its significantly lower acidity. Because cold water does not extract the same acidic compounds as hot brewing, cold brew typically has a pH around 6.3 compared to ~5.1 for hot-brewed coffee. Many people with acid reflux or GERD report tolerating cold brew better than hot coffee, though individual responses vary. If you have severe GERD, consult a physician — coffee of any kind may be contraindicated regardless of brewing method.
Is cold brew coffee ok for diabetics?
Plain cold brew without added sugar or milk contains almost no carbohydrates and has a negligible effect on blood sugar. Black cold brew (or concentrate diluted with plain water) is generally considered safe for people with diabetes, similar to black coffee. The concern arises with commercial cold brew drinks that add significant amounts of sugar, flavored syrups, or sweetened milk — check nutrition labels for these. As with any dietary concern for diabetes management, consult your healthcare provider.
What’s the difference between iced coffee and cold brew?
Iced coffee is hot-brewed coffee served cold; cold brew is never heated. Iced coffee is made by brewing hot coffee at double strength and pouring it over ice (or refrigerating standard-strength hot coffee). Cold brew is made by steeping grounds in cold water for 12–24 hours. The result: iced coffee is brighter and more acidic (like a cold version of your regular morning cup), while cold brew is smoother, sweeter, and lower in acid. Cold brew takes planning ahead; iced coffee can be made in minutes.