How to make Cold Brew Coffee

Table of Contents

Iced coffee sitting on a bench, this is an image on Bean Merchant's blog how to make cold brew coffee and how to make iced coffee.

I remember it clearly. The sun’s rays caressing your skin. The sweat prickling the back of your neck like a thousand baby cacti. The bottoms of your feet burning, as they cry out for shade. 

The clink of ice in a glass. The cooling wash around your mouth. The sweet liquid as it touches the back of your toungue. And the refreshing kick of energy as caffeine spreads throughout your veins. 
Arguably one the most exquisite drinks in existence, cold brew coffee will keep you cool in the long hot summer months. 

What is cold brew coffee?

Cold brew coffee is a method of preparing coffee in which ground coffee beans are steeped in cold water for an extended period of time, typically 12-24 hours. The result is a concentrate that can be diluted with water or milk and served over ice. It can be consumed straight, but drinkers need to be aware that it usually contains more caffeine than coffee brewed in other ways. Cold brew coffee is known for its smooth, less acidic flavor compared to traditional hot brewed coffee.

Cold brew coffee lasts a long time in the fridge, meaning it can be brewed and then consumed for the week afterwards. It’s great mixed with milk, as said above, but can also be mixed with hot water, to create an instant coffee-type drink while retaining the sensational flavours of quality specialty coffee beans. 

What is the best recipe for cold brew?

The number of coffee recipe’s on the internet are as numerous as hairs on my forearm, but we’ve got one that we especially like here at Bean Merchant Headquarters. A coffee recipe is really just a fancy name for a ratio of coffee to water. You’ll find these for different brew methods, including plunger and espresso, and are usually a rule of thumb to go by, with experimentation recommended around the fringes. 

Recipes for cold brew vary. Some think that a ratio of 1:2 coffee to water is good, whereas others suggest that a ratio of 1:5 or even 1:8 is best. This is for a cold brew concentrate though that you would then mix with milk or water. Some suggest that if you don’t want to make a concentrate and want to just drink it straight, you could use 1:17 or 1:18. All I know is that it’s down to personal preference. Like strong coffee? Go for a lower ratio. Like weaker? Go for a higher one.

Bean Merchant Headquarters ratio of choice is 1:8. This means that if you’re using 8 parts water, use 1 part coffee. So if you’re making a cold brew of 500ml of water, you’d mix it with 62.5g of coffee. 

What are the best beans for cold brew coffee.

The best beans for cold brew coffee are typically a medium to dark roast with a good balance of flavour and acidity. The beans should have a strong and bold flavour, but not be too bitter. Some popular options include Colombian, Sumatran, and Ethiopian beans. These beans are known for their rich, full-bodied flavour and notes of chocolate and fruit. Additionally, blends specifically labeled as “cold brew” are also available. These are formulated to produce the best cold brew experience and are typically a mix of different origins.

The biggest tip we can give you around bean choice is to choose beans that are fresh. As beans age, they let of CO2, and lose a lot of their flavours that make them unique. If you want to enjoy the fruity, chocolatey, caramelly flavours of your cold brew, you’re going to want to brew it within around 2 weeks of roasting. All good coffee roasters should have a roast date on their packet. 

There are a lot of different attributes that make choosing the perfect coffee bean for cold brew difficult. The altitude the coffee bean was processed at, the method that the farmer used to process the coffee cherry off the tree, the region it was grown in, even before it gets to the coffee roaster for roasting.

Bean Merchant’s quiz will support you to choose your coffee beans wisely. We’ve gone through every coffee bean on our website, and matched their attributes with best ways to brew. If you’re looking for specialised cold brew coffee beans, let our quiz look for you. Click here to be taken to our coffee quiz, and get matched with the perfect coffee beans for your cold brew brewing. 

How to make cold brew coffee.

Making cold brew is probably one of the easiest ways to brew coffee beans, however it’s also probably one of the longest! 


  • Fresh coffee beans
  • Drinkable water
  • Jar, or french press to brew in
  • Filter (if not brewed in french press)
  • Fridge


Step 1

Grind your coffee at a coarse grind setting. If you grind too fine, your cold brew is going to start tasting bitter. The length of time that the coffee is in contact with the water allows the flavours to infuse well out of the coffee bean even at the coarsest grind setting. Remember to look back at the recipe you’re using. If we’re at 1:8 at this stage we’d be using 62.5g of coffee. 

Step 2

Pour your coffee into your vessel of choice. It’s great if your vessel has some sort of mesh to allow the coffee grounds to brew in the water, with an easy cleanup at the other end. A plunger is a good vessel to use, we’ve also used a jar in the past, and then strained the cold brew coffee through some muslin at the end.

Step 3

Pour your water into your vessel of choice. Remember again to check your recipe. With our cold brew coffee recipe of 1:8 we’re going to use 500ml of water.

Step 4

Give it a stir. Mix those coffee grounds into the water well, all the coffee grounds need to be saturated to allow them to infuse into the water properly.

Step 5

Slap a lid on it. This will stop your cold brew coffee getting that fridge-taste.

Step 6

Put it in the fridge for 24 hours. 

Step 7

Filter the liquid off the coffee grounds – through a tea towel, or a chemex filter, or your plunger if you’ve used this. Put the liquid into a bottle or container and keep it in the fridge. It’ll last up to a week. 

You can drink it straight (it’s concentrate though, so be careful), you can mix it with water (cold or hot to create cold or hot coffee drinks) or you can mix it with milk (to create those oh-so-delicious iced coffees).

What price you should be paying for cold brew coffee.

The price of cold brew coffee in New Zealand can vary depending on the location, brand, and whether it is purchased as a concentrate or a ready-to-drink beverage. In cafes, cold brew coffee is usually sold as a ready-to-drink beverage and can range from around $4 to $8 NZD per cup. If you are buying cold brew concentrate in a bottle or can, the price can range from around $8 to $15 NZD for a 250ml bottle or can. It’s worth noting that there may be a premium for cold brew coffee as it is more time-consuming to make than regular coffee.

This is one of those things that you can absolutely save money on if you brew your own cold brew coffee at home. 

If you buy a 1kg bag of beans from Bean Merchant for $50.00 including shipping, you can make 8 litres of cold brew. That’s worth 40 cans of cold brew coffee from those roasters discussed above, which would set you back around $200.00. 

By brewing at home, you’ve just saved yourself $150.00 that you can put into your rainy day fund. Or that trip fund. Or that treat yourself and get pampered fund.

Now you’re all schooled up on making incredible cold brew coffee, iced coffee, and iced latte. Hopefully you’ve got some tips around how to get the best beans for cold brew coffee, and how to drink it responsibly. Keep cool this summer. If you have any questions or feedback we’d love to hear them below.

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