Coffee & Tea Ratios

Cold Brew Concentrate Ratio (1:4 to 1:5)

Also: cold brew ratio, cold brew concentrate, toddy ratio

1 gram of coarse-ground coffee to 4–5 grams of cold water, steeped 12–24 hours, to produce a high-strength concentrate meant to be diluted before serving.

Cold brew concentrate is produced by steeping coarsely ground coffee in cold or room-temperature water for an extended period — typically 12 to 24 hours — at a very low water-to-coffee ratio. The resulting liquid is 2–4 times stronger than brewed coffee and is intended to be diluted with water, milk, or ice before drinking. Cold extraction at low temperature selectively solvates different compounds than hot water: it favors lower-acidity organic acids and suppresses the volatile aromatic esters that define hot coffee's aroma, producing a cup characteristically smooth, chocolatey, and mellow. The 1:4 to 1:5 ratio (roughly 200 g coffee per 1 litre of water) is calibrated so that a 1:1 dilution with water or milk yields a drink approaching the strength of regular drip coffee.

The proportions

Coffee (coarse ground) · 1Cold or room-temperature water · 4 to 5Steep time · 12–24 hours

1: Coffee (coarse ground) — Coarse grind (similar to French press) maximizes surface area without producing fines that cloud the extract and turn bitter
4 to 5: Cold or room-temperature water — Cold (refrigerator) steep takes 18–24 h; room temperature reduces to 12–16 h but slightly increases acidity
12–24 hours: Steep time — Beyond 24 h the extract develops astringent, vegetal off-notes from over-extraction of chlorogenic acids

Method

Combine coarsely ground coffee and cold water in a jar, pitcher, or dedicated cold brew maker. Stir to ensure all grounds are wetted. Cover and refrigerate 18–24 hours (or steep at room temperature for 12–16 hours). Strain through a fine-mesh sieve lined with a paper coffee filter or cheesecloth, pressing gently but not squeezing grounds (squeezing forces bitter fines through). The resulting concentrate keeps refrigerated up to 2 weeks. To serve, dilute 1:1 with cold water, milk, oat milk, or ice — or use undiluted as a base for cocktails and coffee desserts.

Tips

Use filtered water: cold brew's long steep time magnifies off-flavors from chlorine or minerals in tap water.
Coarser grinds reduce bitter tannin extraction during the long steep — aim for a grind between French press and percolator coarseness.
Do not squeeze the coffee grounds when straining; gravitational drip produces a cleaner, less astringent concentrate.
Room-temperature steeping is faster but more acidic; refrigerator steeping is mellower and more shelf-stable post-brew.
Single-origin light-roast coffees from Ethiopia or Colombia express bright fruit notes even in cold brew; dark roasts produce chocolatey, syrupy concentrates that work well in milk drinks.
For a clarified, glass-clear concentrate, pass through a Chemex paper filter after initial straining — valuable for coffee cocktails.

Variations

Ready-to-drink ratio (1:8 to 1:10)
A single-steep brew calibrated to drink-strength directly without dilution; requires longer steeping or finer grind to compensate
Toddy concentrate (1:4)
Classic Toddy system ratio; 340 g coffee per 1.35 L water, 12 h room temperature steep — the original commercial cold brew process
Nitro cold brew base (1:4)
Higher strength base needed because nitrogen infusion aerates and visually thickens the drink, slightly muting perceived concentration
Cold brew with bloomed grounds
Brief 30-second hot water bloom (2× coffee weight) before adding cold water accelerates extraction and brightens the final cup
Kyoto slow drip (1:10 to 1:15)
Japanese tower dripper produces ready-to-drink strength; not a concentrate — different technique, comparable cold extraction chemistry

Related ratios

French Press Ratio (1:12 to 1:15)
Same immersion principle but hot water reduces steep time from hours to minutes
Espresso Ratio (1:1 to 1:3)
The other high-concentration format; achieved via pressure and 25–30 seconds rather than cold and 18–24 hours
AeroPress Ratio (1:12 to 1:16)
Can be used cold (room-temp immersion) for a fast cold-style coffee, though with distinct extraction character

Appears in

Nitro cold brew on tapCold brew tonicEspresso martini (cold brew version)Cold brew tiramisuAffogato (cold brew poured over gelato)Coffee old fashioned cocktail

References

1.The World Atlas of Coffee — James Hoffmann (2014)
2.The Blue Bottle Craft of Coffee — James Freeman, Caitlin Freeman, Tara Duggan (2012)
3.Toddy Cold Brew System Original Recipe Guide — Toddy LLC
4.SCA Water Quality Handbook — Specialty Coffee Association

Confidence: high

Notes

Why cold brew is low-acid

Hot water is a far more aggressive solvent for chlorogenic acids and certain phenolic compounds that register as brightness or sharpness on the palate. Cold water extracts fewer of these volatile acids over the same dose, even when steep time is extended dramatically. The result is not a failure to extract — the caffeine content of cold brew concentrate is often higher than hot coffee — but a selective extraction that skews toward heavier, sweeter, less acidic compounds. People with acid sensitivity frequently tolerate cold brew far better than hot-brewed coffee.

Concentrate shelf life

Cold brew concentrate refrigerated at 4 °C (39 °F) in a sealed container typically holds quality for 1–2 weeks, with most producers recommending 7–10 days for peak flavor. The absence of heat means none of the oxidative staling pathways that afflict hot-brewed coffee within hours; however, slow bacterial activity and continued extraction from any residual fines will gradually flatten and sour the concentrate over time. Commercial cold brew is often nitrogen-flushed at packaging to extend shelf life to 30–90 days.