Summer is upon us, and many people will be craving their favorite brew in a more season-friendly form. Cold brew is available, and it tends to be sweeter than most other forms of coffee, but it’s also so darn expensive! At Starbucks, a tall cold brew is 50% more than a tall drip coffee!
At home, you can make cold brew with things you already own around the house. All you need is patience, a large container, coffee, and a method of straining. There are several easy ways to do it, so I’ll go over each and recommend tips for how to make it easier.
In general, the basic equipment will be as follows:
- Dry measuring cups or a food scale (scale is better)
- A liquid measuring cup
- Coffee beans (freshly ground is preferred)
- A fine sieve, cheesecloth, a metal strainer, a french press or a cold brew coffee kit
For the following methods, I will start by covering approaches from least to most specialized equipment.
Why Cold Brew Coffee? Cold Brew vs. Iced Coffee
First, not all cold coffee is cold brew. Cold brew, specifically, is coffee that has been brewed (almost) exclusively cold. It is not coffee that has been brewed hot, then cooled off with ice. That would be iced coffee. One method below will start with hot water, but that’s not the main form of extraction.
Cold brew takes much longer to extract the good stuff out of the beans, which reduces the amount of acidity and bitterness that we associate with traditionally made coffee.
The flavor is smoother, it’s better for your teeth and stomach, and it also has a much higher amount of caffeine.
Some believe that, in addition to reducing the negative traits of the coffee, it also removes some of the positive features. Cold drinks are harder to taste as fully, and perhaps some subtleties will be hard to detect. This is the (very worthwhile) trade-off.
I recommend using an older, stale, or suboptimal coffee for cold brew because it will make it a lot more palatable. It’s not a bad idea to use the good stuff, either, but this is a way to enjoy cold brew while also getting rid of the beans you’re not terribly fond of.
Why use a food scale?
The food scale is for more precision when it comes to measuring your beans, as the most accurate measurement for coffee is weight. Why? If you’ve heard the phrase “The darker the bean, the less caffeine”, then you’ll see why.
Dark roast beans expand and fill with air as they roast. The weight is approximately the same as a light roast, so you’ll end up with the same amount of caffeine if you go by weight.
If you go by volume, measuring out scoops and cups, then you’ll get fewer beans due to the dark roasts’ larger beans.
As well, what is a scoop, exactly? There is no international standard for what a scoop entails, so you could range from 7-12g for a single “scoop”. That’s a huge range!
Just something to be aware of when measuring out your coffee. However, for the sake of this article, let’s say a dry cup of ground coffee is roughly 80 grams.
James Hoffman recommends 60g/L as a good starting point, but that’s his recommendation for general, hot coffee brewing.
Others seem to recommend 160g/L. Others still have recommended the wastefully high 200g/L.
Personally, I use 85g/L and found it satisfying. This is the best one I can recommend, as it will result in a cold brew concentrate, which is the goal. That’s roughly a 1:4 ratio (1 cup coffee grounds to 4 cups water).
Method 1 – Immersion Method
The basic equipment for this method are:
- Dry measuring cups or a food scale (1 dry cup of coffee is roughly 80g)
- A liquid measuring cup (optional if you know the size of your container)
- A large container (1L or more)
- Coffee (freshly ground is preferred)
- Water (soft, cold)
- A fine sieve, cheesecloth, flat-bottomed coffee filter, OR a very fine metal strainer
- A rubber band (optional)
The ratio I’ve been using to great effect has been 85g of coffee to 1L of cold water. Others have recommended as much as 200g per liter, but that seems wasteful and excessive to me. Experiment to taste.
The upside to making it extra strong is that you’ll have a strong coffee concentrate, which will last longer – but only so long as all the grounds are able to be submerged. I once tried the upper limit and found that the grounds wouldn’t fit in the water because the container was overflowing.
- Pour ½ cup of cold, filtered water into the bottom of the jug. The water does not need to be filtered, but it is preferred.
- Grind your coffee beans to the coarsest level your grinder can be set to, similar to cornmeal.
- Thoroughly stir the grounds into the water, ensuring no dry pockets remain.
- Continue stirring as you fill the rest of the water.
- Cover with cheesecloth or a flat-bottomed coffee filter (for percolations) and fasten it to the mouth of the container with the elastic. Note: if the filters are old, they can cause mold to infect your brew. (I’ve learned this the hard way).
- Two options for timing and temperature. Remember, longer = more caffeine:
- Room temperature: since it’s warmer, less time is needed. For this method, they recommend 10-24 hours.
- Fridge: 24-48 hours is recommended.
- If you fastened the cheesecloth or filter with the elastic band, pour the liquid through that filter. Use your hand to make sure the elastic doesn’t slip.
- If you didn’t have either of those, you will need a fine metal mesh, or you could try to combine a coffee filter with a strainer. It will be slow, but a filter will remove all of the silt. The fine metal mesh will allow some coffee powder to collect at the bottom, but it’s harmless.
Method 2 – Hot Bloom Method
The benefits of this method aren’t apparent to me; it just lets the coffee de-gas quickly and would start the brewing a little quicker as a result. Likely not a huge change in end results.
Follow Method 1’s steps, but instead of using cold water at the beginning, use hot water up to about ⅓ of the total water volume. Let sit for 60 seconds, thoroughly stir to eliminate dry pockets, then fill with cold water.
Method 3 – Coffee Sock
Coffee socks are what they sound like: a food-grade sock that you fill with coffee to make cold brew. You could probably use other food-grade straining bags, but you’d want to make sure that the fabric is woven fine enough that it won’t let chunks of coffee grains through.
- Grind coffee.
- Fill coffee sock.
- If your sock style allows it, pour the water into the sock directly and stir to ensure there are no dry pockets.
- Once thoroughly wetted, fill the rest of the container with water.
- Seal and place on counter or in fridge.
- On counter: 10-24h
- In fridge: 24-48h
Method 4 – French Press
French presses are great for all sorts of things, but you’d need a fairly sizable one to make this worthwhile. I’d recommend at least a 750ml one, since it will still take 24ish hours to finish brewing.
- Add a small amount of water, about ¼ of the container
- Add coffee, stir in and wet as thoroughly as possible. Aim to eliminate all dry pockets.
- Fill with the rest of the water
- Place on counter or in fridge.
- On counter: 12-24h
- In fridge: 24-48h
- Use plunger to strain the coffee to the bottom, pour to a bottle or container for the cold brew concentrate.
Method 5 – Cold brew kits
Each kit will come with their own instructions, but the most promoted is the Toddy.
You will have to do your best to follow the instructions that come with your gear, which should be fairly easy. The toddy recommended a ridiculous amount of coffee, roughly 4x what I recommend in the ratio section (1:4 is mine; they suggest 1:16 coffee-to-water). At some point, you have to wonder if you’re just wasting beans.
There are several types of kits, but the ones I’ve noticed have these features:
- Fine mesh inserts: these inserts will do a good job of retaining the gross material, like chunks of coffee grounds. It will, however, let through fine coffee powder. Again, it’s harmless, but some people don’t like it – myself included.
- Perforated metal inserts: Near-solid metal cups that have small holes punctured throughout the edges. Same problem as the fine mesh: powder and smaller bits will fall through.
- Coffee socks: More flexible for various containers, it’s more versatile than the first two and is easy to store. Will still let silt/coffee powder through.
- Cloth/paper filters: This will be the best defense against keeping out the extra coffee bits you don’t want. The toddy is my go-to for this reason because it employs a reusable felt filter that will catch all noticeable debris from slipping through. I recommend this one for the cleanest results.
Method 6 – Cold Brew Towers
These are a lot more expensive, require plenty of space, and might be a bit more hassle to clean. Though, they can make a nice conversation piece and add to your decor.
Generally, it will come with a compartment at the top for the water to go in, and a compartment below with ice in it, followed by a spigot on the bottom to control the flow of water. The water will drip into a basket filled with coffee grounds, and it will be gravity-fed into the carafe at the bottom.
Because this is not an immersion brew, you will need to grind it slightly finer than the rest – aim for a medium coarseness, somewhere between brown sugar or raw sugar granules.
- Fill the coffee basket with the grounds.
- Wet the coffee slightly, agitating it to avoid dry pockets.
- Fill your ice compartment (if applicable).
- Fill your water compartment, add stopper, place on top of the tower.
- Adjust the flow rate to ~1 drop per second. Starting slightly faster is ok because it will slow over time as the weight of the water lessens.
Remember that the longer the brew time, the stronger the brew. It’s hard to compare the strength of these brews with the previous methods because it is a finer grind. It will likely result in weaker coffee when compared to the cold brew concentrates.
In general, these towers will require 3-6 hours to complete one batch.
Clean up: run warm water through each piece after every use, then place it back together once it has dried.
Cold brew is simple to make – you just need foresight, patience, and basic equipment. If you don’t mind a little coffee silt in the bottom, then you can probably assemble everything you need with what you have on hand in a normally-stocked kitchen.
I don’t know about you, but I’m never going back to buying $5+ cups of cold brew when I can make it myself for <$5 per liter.
Since it’s summer, keep an eye out for my coming recipes that you can use your cold brew in! I’m developing some flavors you can add to the mix!