Cold Brew Coffee Ratio & Concentrate Dilution Guide (2026)

A cold brew ratio is easy to misread because brew ratio and serving dilution are different calculations.

That distinction explains why one recipe says 1:5, another says 1:8, and a manufacturer later tells you to mix the finished concentrate 1:2 with water.

The first number describes how much coffee and water go into the brewer. The second describes how much finished concentrate and water or milk go into the glass.

Cafe & Crema’s assessment is based on current manufacturer recipes, current manufacturer instructions, general food-storage guidance, and our analysis of how those documented recipes translate into repeatable home workflows. Cafe & Crema has not performed first-party cold-brew testing for this guide.

Cold brew ratio: the short answer

For concentrate, current manufacturer examples sit in a fairly tight band but are not identical:

• OXO full-size Cold Brew Coffee Maker: 284 g coffee with 1,200 ml water, approximately 1:4.2 coffee to water by weight.
• Toddy Home Cold Brew System: 340 g coffee with 1.9 L water, approximately 1:5.6 by weight.
• Toddy cupping protocol: explicitly labels 1:5 as concentrate.

For ready-to-drink strength, Toddy’s current cupping protocol separates several categories:

Brew ratio	Toddy classification
1:5	Concentrate
1:8	Concentrated ready-to-drink
1:10	Strong ready-to-drink
1:14	Typical ready-to-drink

That is more useful than declaring one number universally correct.

If you want one simple home starting point without a dedicated brewer recipe, 1:5 by weight is a reasonable concentrate reference because Toddy documents it explicitly as concentrate. Treat it as a starting point, not a law.

Brew ratio and serving dilution are different calculations

Suppose you brew at 1:5.

That means:

• 100 g coffee
• 500 g water

It does not tell you how strong the drink should be in the glass.

Once filtered, the resulting concentrate can be diluted separately.

OXO’s current full-size recipe uses:

• 284 g coffee
• 1,200 ml water
• 12–24 hours at room temperature

Then OXO recommends serving one part concentrate to two or three parts water or milk.

Toddy’s current home instructions use:

• 340 g coffee
• 1.9 L water
• 8–24 hours at room temperature

Then Toddy recommends starting with one part concentrate to two parts water or milk.

The practical rule is:

First brew to the recipe. Then dilute the finished concentrate to the recipe or to taste. Do not collapse those two ratios into one number.

How to calculate a cold brew ratio by weight

A 1:5 ratio means one part coffee for every five parts water.

Examples:

Coffee	Water	Ratio
60 g	300 g	1:5
100 g	500 g	1:5
150 g	750 g	1:5
200 g	1,000 g	1:5

For water, 1 ml is close enough to 1 g for normal kitchen recipe scaling, so a scale makes the calculation simple.

If your brewer publishes its own recipe, use that first. Manufacturer geometry, filter design and intended yield can differ enough that copying another brewer’s numbers is not always the best baseline.

Why 1:8 can be confusing

The old version of this page called 1:8 a universal ready-to-drink ratio. Current Toddy documentation shows why that is too simplistic.

Toddy’s cupping protocol classifies:

• 1:5 as concentrate;
• 1:8 as concentrated ready-to-drink;
• 1:10 as strong ready-to-drink;
• 1:14 as typical ready-to-drink.

So when you see “1:8 cold brew,” ask what the recipe expects you to do next.

A 1:8 brew may be intended to drink as-is, to pour over ice, or to dilute further depending on the method and target strength.

How long should cold brew steep?

There is no single universal steep time across current manufacturer instructions.

OXO full-size brewer

OXO currently says to steep its 284 g / 1,200 ml recipe at room temperature for 12–24 hours.

OXO compact brewer

OXO’s compact instructions allow:

• 12–24 hours on the counter; or
• 20–24 hours in the refrigerator.

Toddy Home

Toddy currently specifies 8–24 hours at room temperature.

Those windows overlap, but they are not identical.

That is why this refresh removes the old claims that anything under twelve hours is automatically underdeveloped or that one fixed range is universally best.

If you want to change the result, change one variable at a time: ratio, grind, steep time or temperature. Otherwise you will not know which change mattered.

What grind size should you use?

Current OXO and Toddy instructions both call for coarse-ground coffee.

That is a useful starting description. A universal numeric grinder setting is not.

Different grinders number their dials differently, and the same number can represent completely different burr gaps.

If your grinder produces a lot of fines at a coarse setting, filtration can become slower and the cup can carry more sediment. The burr grinder explainer covers why burr system, adjustment and grind path matter more than copying a number from somebody else’s grinder.

For actual grinder choices, use the best coffee grinders or best manual hand grinders guides.

How to dilute cold brew concentrate

Use the concentrate recipe you actually brewed.

OXO starting point

OXO recommends:

• 1 part concentrate
• 2–3 parts water or milk

For a 60 ml serving of concentrate, that means roughly 120–180 ml water or milk before ice.

Toddy starting point

Toddy recommends:

• 1 part concentrate
• 2 parts water or milk

These are starting points, not taste rules.

If the drink is too strong, add more water or milk. If it is too weak, use less dilution next time.

The important part is consistency: brew the same concentrate recipe first, then change the serving dilution. That keeps the variables separate.

Cold brew with milk

A milk drink is still two calculations:

1. how strong the brewed concentrate is;
2. how much concentrate you mix with milk.

OXO explicitly includes milk in its 1:2 to 1:3 serving guidance, and Toddy includes milk in its 1:2 starting recommendation.

That is better evidence than inventing a universal “cold brew latte ratio.”

Once milk is added, follow normal dairy-storage rules rather than the concentrate’s manufacturer storage window.

How long does cold brew concentrate keep?

Storage advice should follow the exact recipe and brewer.

Both current manufacturer instructions below say their filtered concentrate can be stored in the refrigerator for up to two weeks:

• OXO full-size Cold Brew Coffee Maker;
• Toddy Home Cold Brew System.

That does not prove every homemade cold brew recipe has the same shelf life.

Cafe & Crema therefore treats two weeks as maker-specific guidance for those systems, not as a universal safety guarantee.

For refrigerator temperature, FDA guidance says to keep the refrigerator at 40°F / 4°C or below and to keep refrigerated foods covered.

A sealed carafe also reduces refrigerator-odor pickup and accidental contamination. If storage workflow matters to you, the coffee canister guide covers sealed coffee-storage designs for beans; for brewed concentrate, use the sealed carafe or bottle recommended by the brewer.

Room temperature or refrigerator?

Both methods appear in current manufacturer instructions.

• OXO full-size: 12–24 hours at room temperature.
• OXO compact: 12–24 hours on the counter or 20–24 hours in the refrigerator.
• Toddy Home: 8–24 hours at room temperature.

The safe editorial conclusion is not that one is universally better. It is that time and temperature are part of the brewer recipe.

Start with the documented method for your equipment before experimenting.

Do you need a dedicated cold brew maker?

No.

The ratio logic works in any vessel that can hold coffee and water and then filter them cleanly.

A purpose-built brewer mainly changes workflow:

• how the grounds are contained;
• how the water is distributed;
• how the concentrate drains;
• how easy the vessel is to clean and seal.

If you make cold brew regularly, the best cold brew makers guide compares current OXO, Toddy, Hario and Takeya designs.

If you already own another immersion brewer, French press, AeroPress and moka compared helps explain which methods share similar immersion logic and which do not.

A repeatable starting workflow

If your brewer has no published recipe and you simply need a controlled baseline:

1. Weigh the coffee and water.
2. Start around 1:5 by weight for a concentrate reference.
3. Grind coarse.
4. Keep steep time and temperature fixed for the first batch.
5. Filter completely.
6. Refrigerate the finished concentrate promptly in a covered container.
7. Start serving around 1:2 concentrate to water or milk and adjust in the glass.
8. Change only one variable in the next batch.

This workflow is intentionally conservative. It borrows the ratio and dilution logic from current manufacturer examples without pretending every brewer extracts identically.

Sources & Evidence

1. Toddy — Home Model Brewing Guide — primary manufacturer evidence for 340 g coffee with 1.9 L water, coarse grind, 8–24 hour room-temperature steep, refrigeration for up to two weeks, and a starting serving dilution of one part concentrate to two parts water or milk. https://toddycafe.com/cold-brew/instruction-manual
2. Toddy — Cold Brew Cupping Protocol — primary manufacturer evidence separating 1:5 concentrate, 1:8 concentrated ready-to-drink, 1:10 strong ready-to-drink and 1:14 typical ready-to-drink categories. https://toddycafe.com/downloads/Toddy_cold_brew_cupping_protocol.pdf
3. OXO — How to Use the OXO Cold Brew Coffee Maker — primary manufacturer evidence for 284 g coffee, 1,200 ml water, coarse grind, 12–24 hour room-temperature steep, up-to-two-week refrigerated storage and 1:2–1:3 serving dilution. https://www.oxo.com/blog/coffee-and-beverages/how-to-use-the-oxo-cold-brew-coffee-maker
4. OXO — Compact Cold Brew Coffee Maker Instructions — primary manufacturer evidence for 175 g coffee with 700 ml water, 12–24 hour counter or 20–24 hour refrigerator steep, 1:2–1:3 serving dilution and up-to-14-day refrigerator storage. https://www.oxo.com/blog/coffee-and-beverages/how-to-make-cold-brew-coffee
5. U.S. Food and Drug Administration — Are You Storing Food Safely? — general refrigerator guidance supporting 40°F / 4°C or below and covered refrigerated storage; used here for general storage hygiene, not to set a cold-brew-specific shelf life. https://www.fda.gov/consumers/consumer-updates/are-you-storing-food-safely

Frequently asked questions

What is a good cold brew concentrate ratio?

There is no single universal concentrate ratio. Current manufacturer examples cluster around roughly 1:4 to 1:6 coffee-to-water by weight. OXO uses 284 g coffee with 1,200 ml water in its full-size brewer, while Toddy's current home recipe uses 340 g coffee with 1.9 L water. Toddy's cupping protocol also labels 1:5 as concentrate. Use the recipe for the brewer you own, then adjust taste after you understand the baseline.

What is the difference between cold brew ratio and dilution ratio?

The brew ratio describes coffee grounds to brew water before extraction. The dilution ratio describes finished concentrate to water or milk in the glass. They are separate calculations. OXO's current full-size recipe uses 284 g coffee to 1,200 ml water, then recommends one part concentrate to two or three parts water or milk when serving.

How long should cold brew concentrate steep?

Follow the exact brewer recipe. OXO currently specifies 12–24 hours at room temperature for its full-size cold brew maker and 20–24 hours in the refrigerator for its compact model. Toddy's current home instructions specify 8–24 hours at room temperature. Those ranges show why a single universal steep time is not defensible across every brewer.

How do I dilute cold brew concentrate?

Start with the manufacturer guidance for the concentrate you made. OXO recommends one part concentrate to two or three parts water or milk. Toddy recommends starting with one part concentrate to two parts water or milk. Adjust from there rather than assuming every concentrate has the same strength.

How long does cold brew concentrate keep?

Use the storage guidance for the exact brewer and recipe. Both OXO and Toddy currently state that their filtered concentrate can be refrigerated for up to two weeks. That is manufacturer guidance for their systems, not a universal shelf-life promise for every homemade recipe. Refrigerate promptly after filtering and keep the refrigerator at 40°F / 4°C or below.

Should cold brew be made at room temperature or in the refrigerator?

Both appear in current manufacturer instructions. OXO's full-size brewer uses a 12–24 hour room-temperature steep, while its compact brewer allows 20–24 hours in the refrigerator. Toddy's current home instructions use 8–24 hours at room temperature. Follow the maker's recipe before changing both temperature and time at once.

What grind size should I use for cold brew?

Current OXO and Toddy instructions both call for coarse-ground coffee. The exact grinder setting depends on the grinder and brewer, so use coarse as the starting description rather than copying a numeric setting from a different grinder.

Is 1:8 cold brew a concentrate?

It depends on the context. Toddy's current cupping protocol classifies 1:5 as concentrate, 1:8 as concentrated ready-to-drink, 1:10 as strong ready-to-drink, and 1:14 as typical ready-to-drink. That is a useful reminder that the same number can mean different serving intentions in different recipes.