In the past few years, cold coffee drinks – especially cold brew and flash brew – have become extremely popular across coffee shops. However, as well as their sudden growth in out-of-home hospitality businesses, they’ve also become more popular at home too.
It’s a good thing, then, that brewing cold coffee at home has never been easier. Whether you’re making cold brew, flash brew, or other cold coffee beverages entirely, they offer a fantastic way to experiment with new flavour profiles.
Read on to learn why cold coffee is such a hit at the moment, how to brew it at home, and why using the right beans and equipment can make all the difference.
Why are cold coffee drinks so popular at the moment?
In recent years, the demand for cold coffee has grown tremendously. Last year, customers ordered an estimated 373 million servings of cold brew and 2.8 billion servings of iced coffee around the world.
Younger generations, particularly millennials and Gen Zs, are driving this growth in particular. Cold coffee offers both convenience and versatility, which are both popular with these demographics.
Cold coffee drinks – especially those in RTD formats, like canned cold brew – provide an easy on-the-go option, and are also suitable all year round.
Danny Pang is Technical and Sales Manager at Marco APAC. He explains that cold coffee drinks are also becoming more prominent as more brands realise how much potential there is.
“The cold brew trend is growing positively on the whole, as businesses start to realise the operational convenience and consistency of using cold brew concentrate to produce their cold coffees,” he says.
Alongside this, if we look back to 2020 and 2021, we saw how home baristas and “prosumers” were forced to find alternative ways to enjoy coffee at home. This is another reason why home-brewed cold coffee has become so popular.
How to make cold brew at home
Many coffee drinkers are familiar with cold brew coffee, which brews over an extended period of time to create a sweet, smooth, mellow drink with low acidity.
René Kallus is the Key Account and Tech Support for EU at Marco Beverage Systems. He explains that unlike with hot coffee, there are very few things that can go wrong when making cold brew.
“To make basic cold brew coffee, you just need a container, coarsely ground coffee, and a filter of some kind,” he adds.
Your container can be anything from a bucket to a jug – provided it is food safe. Some home baristas use a French press (or cafetière) as it already comes with a filter.
However, remember that when you brew it in this way, cold brew generally ends up being a strong concentrate that may need to be diluted before drinking.
“The simplest method is to grind and soak coffee grounds in ambient temperature water and leave it in the fridge or at room temperature overnight,” Danny explains. “A one litre vessel is enough to produce a decent 1:2 coffee concentrate overnight, depending on the grind size used. The coffee slurry is then filtered and can be diluted to taste over ice.”
René adds that by brewing at a lower temperature, you avoid the bitterness or acidity typically associated with hot coffee, and instead create a more mellow and smooth flavour profile.
Generally speaking, coffee professionals recommend using a 1:4 to 1:8 coffee-to-water ratio for cold brew concentrate; if you want to brew something that’s less concentrated, you can opt for a 1:11 or 1:12 ratio.
Concentrate has a number of advantages, however. Firstly, it’s got a much longer shelf life (it can typically be stored for up to a week and a half in the fridge). It’s also much more versatile – you can add a concentrate to cocktails, milkshakes, or desserts, or even use systems like the Marco POUR’D to dispense it on demand.
How to make flash brew at home
Separate to cold brew coffee is flash brew coffee, also known as cold filter coffee or Japanese-style iced coffee. This is made similarly to a standard pour over – the only difference is the temperature.
“Simply brew your filter coffee hot with your favourite V60 or Kalita dripper, and let it brew over ice,” Dann explains. “You need to reduce the amount of hot water you use, as you need to adjust to account for the water dilution from the melting ice.”
More specifically, the brewing “water” should be 65% hot water (poured over the coffee) and 35% ice (which the coffee drips over). It’s helpful to weigh the brew water and ice individually to ensure a balanced final cup.
Flash brew is good if you want some slightly more complex and nuanced flavours. Unlike cold brew and iced coffee (which are usually sweet and mellow), flash brew preserves more of the acidity and bitterness to create a lighter, more delicate flavour profile closer to filter coffee.
Although a basic filter coffee setup will do the job, Marco’s Ottomatic Coffee Brewer automates the process, resulting in a more consistent brewing experience.
The Ottomatic’s iced coffee mode accounts for the use of ice to avoid diluting the cup too much. To adjust it accordingly, it disables the heating element on the heating plate at the base during brewing to make sure the ice doesn’t melt too fast.
René cautions, however, that this isn’t as straightforward as making cold brew – pour over coffee has number of variables that you need to manage.
“There is a delicate balance for extraction, especially with hot coffee, as we only want certain substances to be extracted. If you brew it over too long a period or use water that’s too hot, you can end up with burnt flavours or a tangy mouthfeel.”
He explains that by carefully dispensing water from its pulsing spray head, the Ottomatic manages all of these variables perfectly.
“Once you set the grind size of the coffee, the same coffee should generally brew to the same level of extraction over the course of several brews,” Danny adds.
Tips and tricks for brewing the best cold coffee
The first thing you need to do if you want to brew high-quality cold coffee is find some specialty-grade coffee beans.
“If you like your cold brew or cold filter coffee on its own and wish to taste the complex acidity in coffee without the adulteration of milk, then use a lighter roast,” Danny suggests. “If you like a low-acidity coffee and love a rich, smooth body, then choose a darker roast.”
Darker roasts are great for cold brew in particular, which brings out more sweet and smooth flavours. They also pair well with milk, which complements common flavour notes such as chocolate, caramel, and brown sugar.
Another consideration is the coffee’s origin. Brazilian coffee, for instance, is commonly associated with chocolate and nut notes, while coffees from East Africa tend to be more floral or citrusy.
René adds that he prefers Ethiopian coffees like Yirgacheffe and Sidamo for cold coffee. He says cold brew can emphasise these coffees’ fruity and floral notes without adding bitterness.
No matter which coffee is used, remember that grind size plays an important role. For cold brew, the coffee needs to be coarsely ground. If it’s too fine, you’ll end up with a muddy and overextracted beverage.
For flash brew, meanwhile, experts suggest that you grind slightly finer than you would for pour over coffee.
Ultimately, flash brew and cold brew present an opportunity for home baristas to experiment with new cup profiles while also offering a fresh, cool beverage.
Furthermore, if you want to keep drinking cold coffee made perfectly, continue investing in an automated brewer like the Marco Ottomatic. By managing all the brew variables precisely, the Ottomatic can help you get the best out of your coffee – whether it’s hot or cold.
