What is cold brew coffee?
We love cold brew and frankly, I’m surprised it’s taken us this long to answer exactly what is cold brew coffee. We have covered a lot of different brewing methods including Vietnamese and Greek coffee but never cold brew.
We know, cold brew isn’t really “coffee” in the traditional sense but it has become commonplace for roasters and cafes to offer a version of it-especially in hot South Florida. Visit your local coffee shop and you’ll undoubtedly notice cold brew has gained some popularity in the past few years.
The Temperature Factor
Probably the most important part in answering “What is cold brew coffee?” is talking about the temperature of the water. Temperature is what puts the cold in cold brew.
When making cold brew you are using room-temperature or cold water which is a bit odd. Normally, when making a cup of morning joe, you heat the water to right around 200 degrees Fahrenheit and pour it over top of premeasured coffee grinds. This is called extraction.
Remembering back to science class, particles move much faster in hot water than cold water. This means coffee particles are able to dissolve easier and faster in hot water than cold. Heat is what brings out some aromatic and flavor properties in the final product. With cold brew, we have to replace heat with something else to fully extract the grinds. That brings me to the next point– Time.
The Time Factor
Since we do not have the luxury of using heat in the extraction, we replace heat with time. Cafes can extract their cold brew anywhere from 8 to 48 hours. 48 hours is a bit excessive. I have only met one barista who did his cold brew this way and it wasn’t to my liking. 12-24 hours is the prime window for extracting cold brew.
The Brewing Method
There are a couple different ways to extract cold brew. One method is to use a filter bag and fully submerge the coffee grinds inside a vessel of water. This is known as the immersion method. The CoffeeSock is a great example. Our experience is immersion cold brew produces the weakest coffee. This is okay for some casual coffee drinkers, but not for true cold brew fans.
Another is the drip method. The drip method produces the strongest coffee. Room temperature water drips over top a bed of coffee and then passes through all the grinds before emptying into the vessel beneath. If a coffee shop is using the drip method for its cold brew, you might notice something that looks like this behind the counter.
The last option is what we call the “free-floating” method. This is where you take a vessel of water and add grinds to it, unfiltered. Later, the grinds are filtered out to immediately halt extraction. This brew method allows the grinds to be stirred periodically, further extracting the coffee through agitation. Familiar with Toddy?
The Grind Settings
Most baristas use a medium to coarse grind. I’ve tried making cold brew using the fine setting on my burr grinder and believe me when I say it’s not pleasant. Fine grinds will over–extract, producing a bitter and sometimes sour taste. For the sake of getting that perfect smooth flavor, you’ll want to use coarse grinds. The surface area of the beans is much larger hence extracting at a reduced rate. That’s what will give you a smoother flavor- a slow and even extraction.
The Ratio Factor
Next, let’s talk about ratios. The goal isn’t to make a ready-to-serve result. Cold brew is made as a concentrate and then later diluted with water. The coffee-to-water ratio will help determine the strength of that concentrate. To give an example, a regular pour-over coffee uses a ratio of about 1 part coffee to 16 parts water extracted over the course of 2-3 minutes. This can deviate depending on the consumer’s preference, but in the instance of cold brew we are talking a whopping 1:4 ratio extracted for up to 24 hours.
The Bean Factor
This is one area of the cold brewing process that is left up to the barista. I have had cold brew made with Ethiopian beans and others made with Colombian beans. Both were delicious and it really just depends on your preference. My recommendation is to use beans that produce a high acid end result when brewed normally. The flavor will be bolder than tea like. Don’t be afraid to use blends as well.
That may have answered, “How do I make cold brew?” better than the original question, “What is cold brew coffee?” We can now surmise cold brew is a chilled coffee concentrate made using a 1 part coarsely ground coffee with 4 parts water extracted over 12-24 hours.
Why cold brew in the first place?
Due to the absence of heat, cold brew contains much less acid than a regular cup of joe. This is great for coffee drinkers with acid sensitivities and easily upset stomachs. If you don’t believe acid content really affects us, take a stroll through the bottled water section at Whole Foods. Guaranteed, most bottles are going to boast about where they fall on the pH scale. What does that mean for cold brew coffee exactly?
It’s a catch-22. Acid is what produces colorful and bright tasting notes, and without it, some say the coffee feels dull and lacking. This is the same reason coffee snobs say arabica beans are superior to robusta.
Iced Coffee vs. Cold Brew
Although the names would lead one to believe iced coffee and cold brew are two in the same, they couldn’t be more different. We already covered how cold brew is prepared, so now let’s look at how iced coffee differs.
For starters, there is a multitude of ways to make iced coffee, Japanese and flash-chilled being the most common. For the purpose of this article, we will be discussing Japanese-style.
The Japanese method is fairly easy.
- Pre-measure grinds (medium) and water in a ratio of 1 to 7.
- Place ice in a cup. Ice should match the weight of the water. Use a new and clean ice-cube tray when making ice for your brew. If the tray has been sitting in the freezer for a week or more, the ice will make your coffee taste funky.
- You can use a Chemex, but I prefer a Hario V60 for brewing.
- Brew overtop of your cup of ice with a 30-second bloom at twice the weight of your coffee.
- Brew time –
Example: 16g coffee, 112g water, 112g ice, 30-second bloom at 32g
Coffee aficionados will tell you to go with this recipe over cold brewing, but why? The Japanese method introduces your coffee to heat, which releases oils and aromas. When the hot coffee drips onto the ice those properties are locked in and diluted therefore giving you a flavorful and acidic cup of coffee. That being said, [Japanese] Iced Coffee can be summed up as a chilled diluted coffee made using 1 part coffee to 7 parts water
Like all coffee based drinks, liking cold brew comes down to preference. Some coffee snobs will stop their feet and say any cold coffee is an abomination and to that, I say “to each their own.” Cold brew can be very refreshing and if served on nitrogen aesthetically appealing as well. Check out our Instagram for tons of cold brew pictures.
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