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The Ultimate Guide to Cold Brew Coffee
Written by: Raj Jana
It began in boutique coffee shops around the world. It moved to the big leagues in Starbucks and Peets. Now you can find it pre-packaged in gas stations. Cold brew coffee is bigger than ever before.
I still remember that first time I was told about brewing coffee in cold water. I thought it was just another scenario where things become more complicated than necessary. I thought it was a strange experiment for people with too much time on their hands. I was wrong.
Iced coffee via cold brewing is delicious and completely legitimate. Whether you’re still a skeptic, or you’ve tasted the wonder of cold brew, this guide will empower you to brew it yourself in your own home.
What Is Cold Brew Coffee?
Cold brew coffee is coffee brewed with cold water. This sometimes means coffee grounds are saturated in cold or room temperature water and allowed to steep for 12+ hours. Other times it means cold water is dripped over a bed of coffee slowly over several hours.
Cold brew coffee is not hot coffee poured over ice. That method of iced coffee brews by some different rules at the molecular level and produces very different results than cold brewing.
Why Is It Special?
There are several reasons cold brew coffee has exploded so quickly over the last couple years. These reasons are so compelling that it makes me wonder why people weren’t cold brewing coffee hundreds of years ago.
Read: What Makes Specialty Coffee Special?
Though both of these things contribute toward and enhance the flavor of coffee, bitterness and acidity can really kill a good cup if they get out of hand with poor brewing. Cold brew coffee doesn’t use hot water, so it doesn’t break down and extract many of the compounds that are responsible for the acidity and bitterness.
With less than half the acidity and bitterness of hot brewed coffee, cold brew feels smooth and forgiving on the palate. You won’t get some of the flavors you would find in hot coffee without the higher levels of bitter tannins and acids (like bright fruity flavors or deep grapefruit), but the results are still striking.
Cold brewing won’t change the flavor of a coffee entirely, but it has a way of presenting it to you in a different way - often with a pronounced sweetness and creamy body. It’s always intriguing to see how the flavors of a great hot coffee come out in a batch of cold brew.
Read: How To: Learn To Taste Coffee!
If you’re a fan of smooth coffee with a very low acidity and creamy body, cold brew coffee may become your best friend.
Easy On The Body
I know how uncomfortable the acidity from most hot coffees can be, especially on an empty stomach. With the low acidity from cold brewing, cold brew coffee is very easy to drink and enjoy, discomfort free!
If you’re sensitive to acidity, cold brew coffee is the way to go.
You Can Brew It As A Concentrate
Cold brew coffee is brewed in a concentrated form. By doubling or tripling the amount of coffee grounds you put in the water, you can double or triple the concentrated strength. If you tried this with hot brewed coffee, you would end up with an under extracted, sour cup of coffee, because each coffee particle didn’t get the amount of water it needed.
Hot brewing takes minutes for balanced extraction to take place. Cold brewing takes hours. This key difference enables us to add extra coffee grounds to the slurry without compromising each particle’s ability to achieve a balanced extraction.
Cold brew concentrate takes up little space, is easier to brew with equipment you probably already have, and opens up a world of possibilities.
All The Possibilities
Hot coffee can be turned into a few different drinks, but the possibilities with cold brew coffee are endless. The concentrated cold brew contains a lot of flavors and mixes well with other ingredients.
Dilute the concentrate with milk and you have a cold brew iced latte. Dilute with soda water and simple syrup, then top with cream for a cold brew cream soda. Mix the concentrate with your spirit of choice and have yourself a caffeinated cocktail. Try a cold brew lemonade (seriously it’s delicious)!
See what I mean? There’s no end to the drink combinations!
I live in a location with intense Summers, and hot coffee just doesn’t sound right when the sun beats down with such ferocity. Cold brew is perfect for those sweltering afternoons.
Two Ways to Cold Brew Coffee
There are two ways that cold brew coffee is made, and both come with their ups and downs.
The most accessible method requires nothing more than mixing coffee grounds with cold water, then filtering it after 12+ hours. I like to use our french press for the brewing, and then our pour over coffee dripper for filtering. The process is very low maintenance and dependable.
Since this is an immersion method, the flavor is full and well-rounded (with the exception of flavors that depend on acidity and bitterness). This is my go-to method for cold brew coffee.
If you want to brew a large batch of concentrate (enough to last several days), and can be available to filter the brew after 12 hours, this is the right method for you.
The slow drip method is more striking visually but is often more difficult to pull off in a home setting. You may have seen this method in the form of glass towers sitting on coffee shop counters with ice in a top chamber, coffee grounds in a middle chamber, and cold brew concentrate in the bottom.
You can accomplish this same style of cold brewing with our pour over coffee maker and an AeroPress by putting ice in the cone and letting it drip down over coffee grounds in the AeroPress. The liquid in the coffee bed eventually falls through the filter into a carafe or mug under the Aeropress.
This method requires more setup and tear down, but it can take as little as 6 hours. The resulting concentrate has a thinner body than the immersion method, but a brighter, crisper flavor.
Since the coffee and water are not in constant contact the entire time and it can be difficult to control the rate that ice melts and drips over coffee, the slow drip method is less user-friendly than the immersion method. If you’re up to the challenge, this method will surely take you on an adventure.
This method makes it hard to brew large batches, but it doesn’t require your full attention after a certain amount of time. When the ice has melted and fallen through, there’s no more brewing taking place. This means you can leave it overnight or all day long, despite it taking only 6 hours or so.
Fresh Coffee Always
Never underestimate the excellence of freshly roasted and ground coffee.
Roasted coffee beans release carbon dioxide and absorb oxygen, which results in oxidation, the same process that turns apples brown and causes iron to rust. As this process happens, the original tasty flavors break down and are replaced with a dull, stale, and bitter flavor.
This decline in quality becomes noticeable after two or three weeks with whole coffee beans, so it’s important to buy coffee from a source that cares about freshness.
Once the coffee is ground, it takes less than thirty minutes for the coffee grounds to experience this rapid decline in yumminess. I suggest grinding your coffee with a burr grinder a couple minutes before brewing, rather than grinding it all at one time. The difference will be very noticeable and you’ll never go back to pre-ground.
Coffee to Water Ratios
Your coffee to water ratio is one of the easiest things to mess up if you’re not being careful, but once you’ve got it down, you’ll be able to rely on it.
Normally with brewed coffee, you would want to use anywhere between a 1:15 and 1:17 ratio of coffee to water. This means that for every 1g of coffee, you use 15 to 17g (or ml) of water. Making adjustments according to the amount of coffee you want to drink or the amount of beans you have is simple from there.
Since you want to brew a concentrate, use a 1:7 coffee to water ratio. For this guide, I’ll be using 100g of coffee and 700g of water to brew the concentrate at 1:7. When I’m ready for a glass, I’ll cut the concentrate with an equal amount of water to bring the final ratio up to 1:14.
Read: How To: The Golden Ratio in Coffee Brewing
In the end, your final glass of cold brew coffee should be pretty close to that normal range of 1:15 to 1:17, which is where most of like our coffee strength. I’ll be aiming for 1:14 because I like my iced coffee to be a little stronger to account for some ice melt.
Be Picky With Your Water
If you don’t really like the taste of your usual water source, you don’t really want to brew coffee with that water. Coffee is mostly water, after all, so use water that you actually like.
Use a Consistent, Medium or Coarse Grind
A coarse grind is ideal for the immersion method. You can use a medium grind size and reduce your extraction time by a couple hours, but the concentrate will take a very long time to filter and the result will not be as clean.
A medium to medium-fine grind is ideal for the slow drip method since the coffee and water have minimal contact over a few hours. Go too coarse and the water will drain in between the grounds without extracting anything delicious out of them. The result will be under extracted - sour and weak.
We have our own burr coffee grinder at JavaPresse that we’ve developed to be effective and affordable. There’s a reason coffee professionals (including myself) say that a good grinder is the most important piece of equipment in a coffee setup.
A Step-By-Step Guide To Immersion Cold Brew Coffee
Gather the tools and ingredients and set it all before you.
- Fresh Roasted Coffee
- French Press
- Filter (I use our pour over filter)
- Tasty Cold Water
- Burr Coffee Grinder
- Kitchen Scale
Weigh out 100g of coffee (about 20 level tablespoons) and grind it coarsely with a burr grinder. Place the grounds in your french press.
Slowly pour 700g (700ml) of water over the coffee grounds, saturating all of them evenly.
After five minutes, use a spoon or paddle to gently submerge any coffee grounds that have created a crust at the top of the brewing slurry.
If the french press won’t come in contact with any direct sunlight or high temperatures, it can be left to brew on a countertop for twelve hours. If it will come in contact with one of those, leave it in the refrigerator to brew for fifteen hours. I usually leave it on the counter overnight.
When the brewing time has elapsed, slowly plunge the french press filter down. To prolong the life of the concentrate, pour it through a second filter and into a container with a lid, then store it in the fridge for up to two weeks.
When you’re ready for a glass, combine the concentrate with an equal amount of water, add some ice, and enjoy!
A Step-By-Step Guide To Slow Drip Cold Brew Coffee
You’ll need some different tools for the slow drip method. Gather them and begin setting up.
- Fresh Roasted Coffee
- 1 Stainless Steel Filter and 1 Paper Filter (2 paper filters will work as well)
- Pour Over Cone
- Tasty Cold Water and Ice
- Burr Coffee Grinder
- Kitchen Scale
Place a filter in the AeroPress filter cap and give it a rinse, then attach it to the brewing chamber. I like to use our stainless steel filter because it allows the oils to get through, which results in a stronger flavor. Cut a second paper filter to be slightly smaller than the first so that it will fit inside the brewing chamber on top of the coffee bed.
Weigh out 30g of fresh coffee (roughly 6 tablespoons) and grind it at a medium-fine setting with a burr grinder. Weigh out 210g of ice (about 12 coarse cubes).
Place the coffee grounds in the AeroPress, filter down, then slide the second filter on top of the grounds for better water dispersion and brewing balance.
Place the AeroPress on top of the AeroPress funnel and over a carafe of some sort (I’m using a mason jar). Set your pour over coffee dripper on top of the AeroPress, and fill it with your ice.
Drop about 1 ounce of cold water (29ml) over the ice to help it begin to melt.
You should see drops of cold water form and fall onto the coffee bed every couple seconds. This process will speed up slowly as the ice melts more quickly.
If your slow drip setup won’t come in contact with any direct sunlight or high temperatures, it can be left to brew on a countertop. If it will come in contact with one of those, find a cooler, darker place or make room for it in the refrigerator.
When the ice has melted, give the brew another hour or so to let the coffee drain from the coffee bed. In total, you can expect the process to take between 5 and 6 hours.
Your cold brew concentrate is already filtered, so all you need to do to enjoy a glass is cut it with an equal amount of water, top with ice, and start sipping.
Cold brewing coffee is usually a forgiving process, but mistakes are easy to make - and thankfully easy to fix. Here are a few problems you may be having, as well as some solutions.
It Isn’t Strong Enough; It’s Too Strong
Most of the time, issues of strength can be resolved by using more or less water when you cut the concentrate. If it’s too strong, add some water to level it out. Not strong enough? Add some concentrate.
You are the ultimate decision maker here, so go with your palate.
If you think you may have brewed the concentrate with an incorrect amount of coffee grounds, don’t be ashamed. I’ve done it too. If you cannot salvage the batch by finding a concentrate to water ratio that’s right for you, it’s time to brew again.
The Concentrate Tastes Bitter or Sour
If you find your cold brew to be a little bitter, it’s likely that the concentrate was over extracted by too much time or too fine of a grind. For immersion, you can reduce the brew time or use a coarser grind. For slow drip, try a coarser grind.
If you find your cold brew to be a little sour, it probably is under extracted and just needs to brew more. Add an hour or two or use a finer grind setting next time if you’re using the immersion method. For the slow drip method, use a slightly finer grind.
Read: How To Pair Your Coffee Brewer With Its Perfect Grind Size
You’ve now stepped into a reality where iced coffee is fantastic, where hot Summer days can be great days for coffee, and where cold brew can change how you think of mixed drinks. It’s a good reality to exist in.
Like with any style or method of coffee brewing, the best cup of coffee is one you enjoy thoroughly. If you happen to like your cold brew a little stronger than I, play with the recipe some and make your concentrate the way you like it. You’re the master of the coffee you drink.
All that's left to do is get yourself a french press and a coffee grinder and get going! You'll be sipping iced coffee in no time.
Chief Brewing Officer
JavaPresse Coffee Company