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Avoid These Mistakes When Making Cold Brew Coffee

Cold brew coffee is one of the most thirst-quenching drinks out there. It allows coffee lovers to enjoy the nutty aromas of their beloved drink whilst not overheating on a hot summer’s day. 

Cold brew coffee differs from iced coffee in the way it is prepared and the way it tastes, despite both being popular chilled coffee drinks. 

Cold brew coffee is actually often confused with regular iced coffee, but there is actually a longer and more detailed process involved in making it the right way than you might think. 

So, if you want to nail the perfect cold brew coffee from the comfort of your own home, and avoid commonly committed mistakes, then you’ve come to the right place! 

What is Cold Brew Coffee?

Cold brew coffee is pretty self-descriptive when it comes to the way it’s made.

Whilst you may see cold brew and iced coffee sitting next to each other in your local coffee house, the way they are made is far from similar!  

Cold brew has been around for centuries. In fact, most coffee historians believe cold brew dates back to the 1600s when it originated in Japan. As with a lot of significant points in the history of coffee, it is difficult to track down exact dates and locations for when the first cold brew coffee was actually brewed, but the point is, it’s been around for a while! 

Cold brew is incredibly popular in the summer months across the world. It tends to have a more mellow, earthy, and subtle taste compared to iced coffee made from espresso, and this comes down to the way it is brewed. 

Since cold brew is made using cold, filtered water, the extraction of the coffee’s oils and flavors happens over a much longer period of time. There is no heat or pressurized water to force the coffee’s flavors into the water, so much more time is needed for this process to take place. 

Where a cup of espresso can be delivered in around 30 seconds, it takes at least 12 hours for a cold brew solution to produce a strong, palatable coffee! 

Iced coffee uses freshly brewed espresso, ice, and milk (or water for an iced americano) to offer a strong, aromatic flavor that is punchy but well-balanced. 

Whereas, cold brew coffee uses just the coffee grounds, time, and no heat at all to produce a more subtle, well-rounded brew. 

Once cold brew coffee has been steeped for a long enough period of time, usually between 12 and 24 hours, it is filtered at least once and this results in ‘cold brew concentrate’. 

This can either be drunk straight away over ice or watered down slightly to make it a little more palatable. 

How to Make Cold Brew Coffee

The method involved in making cold brew coffee is not particularly complicated, but the ingredients used have to be top quality to get the best results. 

If you break it down, all we really need is ground coffee, water, and some ice to serve, right? 

Well, not exactly… 

Using any old coffee bean, ground however you like, and combining it with regular tap water will produce pretty poor results. 

That is because using the wrong grind size will result in over-extracted, bitter coffee that won’t be any good to anyone! 

In general, for cold brew coffee, you can produce either a coffee concentrate or a ready-to-serve coffee solution. Coffee concentrate uses a ratio of around 1 part coffee to 3 parts water, whereas a cold brew coffee that is ready to drink would use 1 part coffee to 7 or 8 parts water. 

The benefit of producing coffee concentrate is that it can be diluted down to make many more cups of cold brew coffee from a single batch, so it is a more efficient way of using your coffee grounds, especially when you have to wait overnight! 

For the purposes of the method shown below, I will be using a ratio of 1 part coffee to 3 parts water to produce a strong, but not overpowering coffee concentrate. 

So, let’s dive into the basics of making the perfect cold-brew coffee! 


  • Extra Coarse Ground Cold Brew Coffee – 1 Cup/200g/7 oz
  • A Glass Jar (for the cold brew coffee to steep in) – Approx 30 oz capacity
  • Cold, Filtered Water – 3 Cups/600g/21 oz
  • V60/Coffee Filter
  • Sieve
  • Serving Glass
  • Ice Cubes
  • Milk (optional)


  • Preparing the Coffee (1 Minute)
  • Steeping and Brewing in the Fridge (12-24 hours)
  • Extracting Coffee and Serving (5 Minutes)


Here is a step-by-step foolproof method to brewing great cold brew coffee from the comfort of your own home, time after time! 

Step 1: Pick Your Beans

The first step to making the perfect cold brew coffee from home is to pick the correct beans for the job. 

Whilst any good quality coffee beans would make a high-standard cold brew, I’d recommend going for a specially roasted “Cold Brew” bean. These are specifically blended to steep well during the long extraction period associated with cold brew coffee. 

Don’t forget, we are brewing coffee using cold rather than hot water here. This extraction method brings out the dark, earthy notes of the beans rather than hot water which tends to extract more vibrant, nutty flavors. 

Therefore, you want to use a bean that will complement this process.  

If you are looking for cold brew coffee beans, check these out on Amazon

Step 2: Grind

Next, let’s talk about grind size. 

The main differences between which size of coffee grind you’ll need comes down to whether you’ll be forcing pressurized water through the grounds or submerging the coffee in water and letting them steep to brew. 

For pressurized coffee extraction; think espresso, moka pot, percolator, Aeropress, etc, you’ll want a very fine grind. 

Whereas for submersion coffee extraction; think the french press, cold brew, drip brew, etc, you’ll want a coarser grind. 

For cold brew coffee, you’ll want to use the coarsest grind your grinder will allow. This ensures that the maximum coffee flavor is extracted overnight. 

Again, since we are using cold rather than hot water to dissolve those coffee flavors into the water, we need to ensure the grind is as robust as possible for the best results. 

Add approx 1 cup/7oz/200g of these coarse coffee grounds to your glass jar and try not to spill any! 

Step 3: Steep in Cold Water

The next step is to add your cold, filtered water to your glass container. Add around 3 cups, 21oz, 600g of cold, filtered water to the glass and shake well to ensure all of the coarsely ground coffee makes contact with the water. 

If you don’t have a water filter but need to order one, here are some of the most popular options on Amazon

Step 4: Leave Overnight

To get the best results and the maximum coffee extraction, you’ll want to leave your cold brew coffee in the fridge for at least 12 hours, but preferably overnight. 

Step 5: Filter Your Cold Brew Concentrate

Once your cold brew coffee has been fully extracted, you’ll need to filter it to ensure you get the perfect, strong coffee concentrate without any leftover sediment or grit. 

Because you will have used coarsely ground coffee, the first filter can be done using a sieve. Simply strain your cold brew coffee through a sieve into a bowl to catch the largest grounds. 

Then, once you have this liquid, pass it through a V60 and standard filter paper to ensure the coffee concentrate is completely free from any sediment. 

Step 6: Serve and Enjoy!

Once you have got your coffee concentrate fully filtered and extracted, it’s time to serve! 

It would be advisable to water down your coffee concentrate before serving. 

The amount of water, ice, and milk you may add to your cold brew coffee is up to you, and it definitely takes some trial and error to get the blend to your liking. 

But as a general rule of thumb, add to your glass approx 1 third coffee concentrate, 1 third cold, filtered water, 1 third ice (and a splash of milk if required). 

Watching the milk cascade down the sides of your chilled glass is one of the most satisfying parts of making a cold brew coffee! 

Simply stir it up and enjoy the fruits of your labor! 

Mistakes to Avoid When Making Cold Brew Coffee

If you follow the steps above, you’ll be sure to make a pretty good cold brew coffee every single time. 

Some experimentation is definitely needed when dialing in your recipe for cold brew coffee, as everyone has different taste and strength preferences. 

However, here are some of the common mistakes that you can avoid when brewing your own cold-brew coffee from home!  

Using a Grind Size Too Small

Since cold brew coffee is steeped for a very long period of time (between 12 and 24 hours generally), a very coarse grind is needed to ensure the coffee oils and flavors are extracted correctly. 

Using a grind size that is too small for this coffee extraction method will result in over-extracted, bitter, and distasteful cold brew coffee.

Using Plain Old Tap Water

Using tap water rather than filtered water can impact the taste and overall quality of your cold brew coffee-making process. 

Different areas have a different hardness of water, and again this can impact the taste of your cold brew. 

For consistent, high-quality results, it is best to pass your tap water through a water filter before adding it to your coarsely ground coffee beans. 

Getting Your Ratios Wrong

One of the biggest mistakes the home coffee brewer can make is using the wrong coffee-to-water ratios when steeping their cold brew mixture. 

In general, a great glass of cold brew concentrate should contain anywhere between 1:3 and 1:4 coffee-to-water ratio. This ensures you have a strong enough coffee concentrate to be diluted, but also that the coffee is extracted properly too. 

However, if you don’t use enough coffee and dilute the grounds too much, you’ll end up with an under-extracted, weak cold brew that is pretty much flavorless! 

Once your coffee concentrate is ready to be served, it would be advisable to dilute it with about 30%-50% freshly filtered cold water. This will ensure your drink won’t be too bitter or highly caffeinated. Also, adding a splash of milk and a little sweetener can take the edge off the intense coffee concentrate. 

Using the Wrong Coffee Beans

Cold brew coffee beans are specifically roasted, ground, and blended to bring out the best in long, cold extraction. 

Bear in mind that the coffee will have a more subtle, earthy, and less acidic flavor profile when compared to coffee that is extracted using hot water. So, using a medium to a dark roast bean that is robust enough to stand up to this drawn-out extraction process is key to ensuring your cold brew concentrate is up to scratch. 

Also, since you are grinding up your coffee very coarsely and leaving it to steep for a long period of time, you should save your ‘Sunday best’ coffee for another day. Use medium to lower-grade coffee beans for cold brew, as you won’t taste the delicate flavor notes of a light roast, high-quality, single-origin bean very easily through the cold brewing process. 

Not Diluting Your Coffee Concentrate Enough

Finally, not diluting your cold brew coffee concentrate enough will result in an incredibly bitter final product. 

Whilst being a coffee hardcore might sound like a good idea, overly strong cold brew coffee isn’t necessarily the same as having a strong double espresso… 

Make sure to dilute your coffee concentrate with at least an extra 30% of freshly filtered cold water and add ice and milk as necessary to ensure the flavor is on point and you taste the underlying coffee flavors, rather than just a sharp bitterness! 


Overall, cold brew coffee is a very refreshing and popular drink that many coffee lovers all over the world enjoy in the summer months. 

Cold brew coffee is a drink that does not require many ingredients to make, but the quality of the inputs plays a huge role in determining the quality of the final product. 

Using medium to dark roast coffee, ground very coarsely, and added to freshly brewed cold water in the correct ratios will ensure you aren’t left with a bitter, over-extracted drink at the end of the process. 

Related Questions

What Happens if You Over Steep Cold Brew Coffee?

Whilst it is difficult to over brew cold brew coffee since it is meant to be steeped for over 24 hours, if it is left too long in the fridge, it will develop overly bitter and woody flavors. 

Cold brew coffee concentrate can generally last for up to 2 weeks in the fridge, but it will gradually become more bitter and less palatable over time. 

Why Does My Cold Brew Coffee Taste Bad?

The taste of cold brew coffee can be upset by either; grinding your coffee even too finely, using low-quality water, not filtering it properly, not letting it steep for long enough, or using too much or too little coffee in relation to water. 

Is 2 Hours Long Enough to Make Cold Brew?

No, cold brew coffee should be steeped in cold, filtered water for a minimum of 12 hours, and even as long as 36 for the best results. If you are looking for a quicker cold or iced coffee recipe, you may be better off making an iced americano

What Happens if You Don’t Dilute Cold Brew Coffee Concentrate?

Drinking coffee concentrate before it has been diluted will give you a very strong, bitter, and overly caffeinated cup of joe. This will not be very pleasant to drink, so it is worth diluting it with between 30% and 50% water to ensure you get the right balance of flavors. 

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