Cold brew coffee: our guide to ratios, beans and infused coffee

Cold brew coffee is a brewing method that uses time instead of heat to extract the oils and flavours from ground coffee. It is a full immersion method, which means the grounds sit in the water for the whole brew, rather than water running through them as it does in a pour-over. The steep runs anywhere from 12 to 24 hours, typically 12 to 18.

Why so long? Extraction, the process of dissolving flavour compounds from the grounds into the water, happens much faster in hot water. That is why a hot filter coffee is ready in minutes, while cold brew needs hours. For context, an espresso takes roughly 25 to 30 seconds and a filter brew two to six minutes. Temperature also changes which compounds come out and how quickly, so the same beans can taste surprisingly different brewed cold.

When the steep is done, you filter out the grounds and keep the coffee in the fridge.

A method, not a bean

Cold brew describes how coffee is brewed, not a type of coffee. You can cold brew any coffee, and one you already know well is a good way to taste what the method does. When we sell cold brew coffee, we mean beans we have selected and roasted to taste their best brewed this way.

Concentrate or ready to drink

You can brew it two ways. A concentrate uses a lot of coffee for the amount of water, so it comes out strong and you dilute it with water or milk before drinking. A ready-to-drink cold brew uses more water from the start, so it can go straight into the glass. The ratio decides which one you end up with.

Cold brew is popular for its smooth, mellow flavour and for how many ways there are to drink it. If you love hot filter coffee, it is also a way to enjoy your favourite coffee cold on a warm day. Here is what the slow, cold extraction gives you.

It tastes less acidic and less bitter. Cold brew generally has lower perceived acidity than the same coffee brewed hot. That is part of why it tastes smooth and rounded.

Acidity is not a fault, though. In specialty coffee, acidity is often the quality people look for: the crispness of apple, the brightness of citrus, the juiciness of stone fruit. Cold brew presents a coffee differently, not better. If you love a bright, lively single origin, try it as an iced coffee too.

It is naturally sweet. Cold brew tastes naturally sweet, with plenty of body.

It is flexible. Drink it on its own, over ice, or with milk as an iced latte. Change the ratio to make it as strong or as light as you like.

It is made ahead. One batch keeps in the fridge for several days, so cold coffee is ready whenever you want it.

It shows off subtle flavours. Cold brew highlights the quieter flavours in specialty coffee. We roast a range of coffees specifically to shine when they are brewed cold.

It needs no special skill. There is no espresso machine to master and no pouring technique to learn. If you can weigh, stir and wait, you can make cold brew.

Cold brew and iced coffee are both served cold, but they are made in completely different ways. Cold brew is extracted with cold water over many hours. Iced coffee is brewed with hot water, often straight over ice, and chilled quickly, so it keeps more of the brightness you would taste in a hot cup.

Neither one is better. They answer different cravings. Choose cold brew when you want something smooth, with lower perceived acidity, that you can make in a batch and drink over several days. Choose iced coffee when you want brightness and origin character in a glass that is ready in minutes.

The best way to learn the difference is to take one bag of coffee, brew half as cold brew and half as iced coffee, and taste them side by side. Our guide to cold brew vs iced coffee walks you through it.

The cold brew coffee ratio is the weight of coffee compared with the weight of water. A ratio of 1:15 means one gram of coffee for every 15 grams of water.

For cold brew, we work between 1:5 and 1:15, depending on the brewing system. That is a wide range, because the ratio decides what kind of cold brew you end up with. The closer you get to 1:5, the stronger the brew and the more you will dilute it. The closer you get to 1:15, the lighter and more delicate the cup.

Working it out. Divide the weight of the water by the second number in the ratio. For 1,000g of water at 1:10, that is 100g of coffee. At 1:15, it is about 67g.

Dilute slowly. When you dilute a concentrate, add water or milk a little at a time and taste as you go until it is balanced. It is easier to add more than to take it back out.

Some coffees have their own recipe. Our Strawberry Scoop is brewed at 1:18 for 11 hours in the fridge, a lighter ratio and a shorter steep than our general range. Every one of our cold brew releases comes with a brew card that gives the grind size, ratio and steep time for that coffee, so start there.

Weigh, don't scoop. Scales keep the ratio accurate. Once you find a recipe you like, write it down. Keeping everything else the same makes it much easier to compare one coffee with another.

The ratio sets the strength, not the cold water. Cold brew has a reputation for being strong, and that comes from the ratio. Brewed as a concentrate, it is strong until you dilute it. Brewed with more water, it is ready to drink.

There is no single right bean for cold brew. The best choice depends on how you like to drink it, and a coffee you already enjoy is a good place to start.

For black cold brew, choose a light or filter roast single origin. Light roasts work best with slow extraction methods like cold brew, and a single origin lets that coffee's particular flavour come through. Single origins are also seasonal, so each new harvest brings new flavours to try. We release new single origins every month, including a filter roast.

For a chocolatey, fuller cup, start with a coffee that already tastes that way. If you enjoy chocolate, caramel and a fuller body, choose a coffee with those notes.

Processing changes the flavour. Natural, or dry-processed, coffees tend to be fruitier and sweeter. Washed coffees are usually cleaner and more delicate. Our guide to single origins and blends explains more.

Freshness matters too. Coffee starts to lose aroma as soon as it is ground, because it oxidises. Grind just before you brew if you can, and keep your beans in an airtight container somewhere cool and dry.

The coffees we roast for cold brew

Our cold brew range is built for cold extraction. Each coffee goes through experimental fermentation at origin, such as extended anaerobic fermentation with fruit or yeast cultures, and we roast it specifically to shine when brewed cold. The aim is a bright, fruit-driven, refreshing cup.

They come in 200g bags, either as whole beans or in our cold brew grind, which is ground coarse for cold brew. Every release comes with a brew card covering grind size, ratio and steep time.

The range rotates, with new cold brew releases through the year. Earlier releases include Lychee Bloom, Passionfruit Sun and Peachy Keen. The newest is Strawberry Scoop, and its recipe is further down this page.

Making cold brew is simple. The hard part is waiting.

You need coffee, a grinder, scales, filtered water, a spoon or paddle to stir with, a brewer or a jar or jug to steep in, a filter, and a container to keep it in the fridge. Paper, cloth and reusable nylon filters all work. Rinse paper filters first to remove any paper taste.

1. Weigh your coffee and water to your chosen ratio.
2. Grind the coffee medium-coarse, just before you brew. A coarser grind has less surface area, so it releases flavour slowly, which suits a long brew.
3. Combine the coffee and water, and stir at the start so every ground is saturated and the coffee extracts evenly.
4. Cover and steep for 12 to 18 hours, in the fridge or at room temperature.
5. Filter through a fine mesh sieve or a cold brew filter, then refrigerate.
6. Serve over ice, diluted with water or milk to taste.

Cold filtered water is best, but cool or room-temperature water works. Water makes up the vast majority of every cup, and its mineral balance changes how the same coffee tastes, so our guide to water for coffee is worth a read.

Taste as you go. The lighter, more acidic compounds in coffee dissolve first, then sweetness, then body, and finally the heavier, bitter compounds. So under-extracted cold brew tastes sour and lacks sweetness, while over-extracted cold brew turns bitter.

A dedicated brewer makes the job tidier. The Hario Cold Brew Pot is a one-litre glass pot with a permanent filter inside, and it steeps in the fridge for 12 to 18 hours for a clean, smooth cup. The Toddy cold brew system steeps in the fridge or at room temperature and is made for larger batches, which keep refrigerated for up to seven days. It brews tea as well as coffee. Todd Simpson, a chemical engineering graduate, developed and patented the Toddy system in 1964.

Infused coffee is coffee processed with fruit, spices or specially selected yeasts added during fermentation, at origin and before it is roasted. The additions enhance or transform the coffee's natural flavours, bringing out notes like tropical fruit, florals or subtle spice.

Why producers infuse coffee. Infusion lets farmers widen the range of flavours they can offer and craft unique, high-quality coffees. It adds value, meets global demand for new flavour profiles, and gives producers more control over how the final cup tastes.

How it is done. Fermentation is where much of a coffee's flavour develops, and producers now borrow techniques from winemaking to shape it. In anaerobic fermentation, coffee cherries go into sealed tanks with the oxygen removed. The process is slower, which gives flavours more time to develop, often into bold, fruity or wine-like notes. Adding fruit, or a particular yeast strain, steers how those flavours develop. Each yeast strain behaves differently: some bring out fruit, while others bring out floral, spicy or creamy qualities.

Our recent cold brew releases all used a 72-hour dry anaerobic fermentation with fruit added:

A closer look at Lychee Bloom. Lychee Bloom came from Finca Santa Mónica in Armenia, Quindío, Colombia, and was 100% Castillo variety, honey processed. Honey processing has nothing to do with honey: the sticky, sweet layer of fruit on the bean, called mucilage, is left on while the bean dries. The cherries spent 72 hours in sealed anaerobic tanks, with lychee fruit and wine yeast added during fermentation. The result was tropical, floral and juicy sweetness with a balanced flavour.

Why they suit cold brew. We roast these coffees specifically for cold brew, where their fruit-driven flavours come through bright and refreshing. They are best enjoyed chilled or over ice.

To read more about how producers use fermentation, including carbonic maceration and thermal shock, see our guide to experimental fermentation.

Strawberry Scoop is a fruity, refreshing coffee made for cold brew. The cherries go through a 72-hour dry anaerobic fermentation with ripe strawberries and wine yeast, before they are pulped and dried on raised beds. The strawberries lend their natural sweetness and the wine yeast adds aromatic complexity and depth, so the cup is full of ripe strawberry notes.

Our recipe:

• Ratio: 1:18. For example, 50g of coffee to 900g of water.
• Grind: coarse, or buy it in our cold brew grind.
• Steep: 11 hours, in the fridge.

1. Coarsely grind the coffee and combine it with filtered water in your brewer, stirring until all the grounds are wet.
2. Cover and steep in the fridge for 11 hours.
3. Filter through a sieve or a cold brew filter.
4. Serve over ice, diluting with water or milk to taste.

Strawberry Scoop is naturally bright and balanced, so it needs very little help. Mix it with milk for a fruity iced latte, and sweeten it lightly if you like. It makes a refreshing summer drink.

Brewing it for the first time? We pair Strawberry Scoop with the gear to brew it. The Strawberry Scoop Hario Cold Brew Kit has the one-litre Hario Cold Brew Pot, a 200g bag and a Beastman MiiR tumbler. The Strawberry Scoop Toddy Cold Brew Kit is for larger batches, with the Toddy system, a MiiR Tomo thermos with sipping mugs and a 200g bag. The Strawberry Scoop Paradox Cold Cup Kit pairs a bag with our Paradox Cold Cup, which has a splash-proof lid and a straw, for cold brew on the go.

A few ways to drink it:

• Over ice. If it is a concentrate, dilute it first, and remember that melting ice waters it down too.
• With milk. Add milk for an iced latte. A fruit-driven coffee like Strawberry Scoop makes a fruity one.
• As a Strawberry Cream Cold Brew. Our Strawberry Cream Cold Brew tops cold brew over ice with a strawberry cream, whisked from cream, vanilla, milk and strawberry syrup until it foams.
• As a Cold Brew Yuzu. For something citrusy, our Cold Brew Yuzu shakes cold brew with yuzu syrup, vanilla and lemon juice, then strains it over ice.
• Straight from the can. Our Kenyan cold brew cans are ready to drink, chilled or over ice. Each 250ml can is made with a single origin Kenyan natural coffee, with plum, toffee and chocolate notes, and they come in packs of four or 16.