How To Make Cold Brew In Mason Jar At Home

We review and suggest products independently, but if you buy a product via the links in our posts, we may earn an affiliate commission at no cost to you.

Black Friday 2022! Click Here to check our selected coffee deals.

Iced coffee, we all love it, especially in the hot summer. There are so many gadgets and recipes out there to make cold brew coffee. If you’re a do it yourself person, and you want to do it at home, even a mason jar and a filter bag or a cheese cloth will get you there.

If you strip down the process of making cold brew, all you really need is a container, some sort of straining devices, and coarsely ground coffee. Simply grab the coffee, immerse it in cold water and allow it to infuse. 

One of the most popular methods of making cold brew is using a mason jar. Many people just have one laying around. This is a really easy way to make cold brew without buying anything extra cold coffee brewer or coffee gear. 

Before we get started, let’s clear something up.

Cold Brew vs. Cold Brew Concentrate

Cold brew coffee concentrate is much stronger than a ready-to-drink cold brew coffee.

Both can be made through the same cold brewing process. You let the coffee ground steep in the cold water for more than 12 hours and strain the coffee out. 

The only difference is the coffee to water ratio.Coffee concentrate uses a greater amount of coffee, like 1:6. You’ll want to dilute the coffee concentrate with water or milk. While the ready to drink cold brew coffee uses 1:15 ratio, which is similar to the drip or French press coffee.

In the following brewing guide, we are making the cold brew coffee concentrate with a Mason Jar – a really strong coffee concentrate. You’re going to dilute it with water or milk to make more cold brew coffee. 

Things To Know Before You Make Cold Brew Coffee

1.Coffee Grind Size

Since the coffee grounds will be steeped in the cold water for more than 12 hours, it requires a coarser grind size. The logic behind this is very straightforward, the more contact time between the coffee and the water, the more extraction. If you use a fine grind to make a cold brew, the coffee will be over-extracted in such a long time. To check out the right grind size for cold brew, please check out this coffee grind chart


2. Cold Brew Ratio

Here we will make a jar of concentrated coffee. You can store it in the fridge for a week and dilute it into several cups of cold brew drinks. We will use a 1:6 coffee to water ratio, which means we use 50 grams of grounds and get 300 ml (10 oz) of coffee.

If you are making a cup of cold brew that is ready-to-drink without dilution, the 1:15 brew ratio is good to go. However, do you really want to spend a whole day making one cup of coffee? 

3.Brew Time 

Normally it takes 12-24 hours to make a cold brew. The longer the steeping time, the stronger coffee you have. Don’t let the water extract the coffee for more than 24 hours. You may get more bitterness in the coffee. Less than 12 hours, the coffee will be too weak since we are using coarsely ground coffee. 16-18 hours is a good starting point, you can find your own sweet spot base on your taste preference next time. 

4.Things We Need

To make a cold brew, you’re going to need five things, a brewer (A mason jar in this guide), a spoon, water, a stainer, and of course, the coffee. It’s great if you have a coffee grinder so you can ensure the freshness of your coffee. However, if you don’t have a grinder, use the coarse preground coffee you got from the supermarket is totally fine. You can also make French press cold brew if you have one.


5.What Coffee Is Best For Cold Brew 

Honestly, all coffee works. Just pick your favorite coffee beans. Some coffee lovers prefer lightly roasted coffee. At the same time, some believe the cold brew coffee concentrate should have a richer, darker flavor, so an espresso blend can make a better coffee concentrate. There’s no right or wrong, but just your taste preference.  In fact, cold brew is a very forgiving coffee brewing method, it will cut the bitterness and the adicity of the coffee during the brewing process. So it tastes smoother than hot brew coffee. Check out our cold brew coffee beans reviews for more options.

Step by Step Guide To Make Cold Brew in a Mason Jar

Now you have the basic ideas you need to pay attention to while making cold brew in a mason jar. Let’s get started and make your DIY cold brew coffee at home. 

Time needed: 16 hours.

Mason Jar Cold Brew Instructions

  1. Weigh coffee beans (Or preground coffee)

    If you have a kitchen scale, weigh 50 grams of whole coffee beans. It’s always recommended to measure the amount of coffee and water so you can make consistent coffee. If you don’t have a scale, use 3-4 tablespoons, or just eyeball it.

  2. Grind the coffee beans 

    Use a coarse grind setting of your coffee grinder to grind the coffee beans. It’s about the size of peppercorns. 
    Tips: It’s good to use a good burr grinder since it’s challenging to get uniform coarse grounds for some blade grinders. The fine particles will be over-extracted and present unpleasant notes in your final cups. 

  3. Add water to a mason jar

    Pour the water at room temperature into the mason jar. Since we use 50 grams of coffee, we need to add 300 ml (10 oz) of water using a 1:6 ratio. You can use a spoon to stir the coffee grounds and wet them as evenly as possible.  

  4. Wait for 12-24 hours

    This is the most difficult part. You’d better put the mason jar in a corner and try not to pay attention to it. Leave it there for 16 hours. 

  5. Decant and Strain the coffee

    The next day, remove the lid and you are going to pour the cold brewed coffee into another mason jar or any decanter through coffee filters. That depends on what you have at home. 
    If you use a mesh strainer as a coffee filter, there’s gonna be a lot of tiny bits left in your cup, which makes it tastes gritty. 
    Cheese cloth is better coffee filter but it can get really clogged up, especially by coffee grounds. The concentrate you filtered with cheese cloth is still not really clean. You can taste and feel the sediment in your mouth. 
    And if you think sediment in hot coffee is unpleasant, it’s even worse in a cold drink. If you have a filter paper, that’s awesome. It’s good to filter the coffee again to reduce the sediment.

  6. Serve the cold brew coffee

    Now we’ve got the cold brewed coffee concentrate, the best bit, it’s time to serve it up. 
    For a basic black cold brew, take a chilled glass, add some ice and pour one part cold brew concentrate and then one to two parts cold water. You can adjust the amount of cold water depending on your own preference. 
    If you like milk, the same thing but we substitute the water for milk. Take a chilled glass, add some ice and pull one part of concentrate, then two parts milk or whatever milk alternative you want. 

  7. Store the rest in the fridge

    If you have some coffee concentrate left, screw the lid on the mason jar and store it in the fridge for up to 12 days. Whenever you need to drink the iced coffee, just add some water and milk and enjoy. 
    If you are caffeine addictive as we do, usually a jar of coffee won’t last for 3 days. 🙂

Final Thoughts About Cold Brewed Mason Jar Coffee

That’s how to make cold brew concentrate using Mason Jars at home without any coffee makers. It’s simple, cheap and very easy to repeat on a day to day basis. You can make a big jar of coffee concentrate at the weekend and enjoy cold brew drinks for a whole week. How amazing!


Can You Make Cold Brew in a plastic container?

Sure, you can make cold brew following the brew guide above in any watertight vessel you can find in your kitchen, such as Mason jars, a bowl, a glass vessel, or even a plastic container. As long as it is large enough to contain the water and coffee. 

Should you make cold brew coffee in the fridge or at room temperature?

Both work, you can either make a cold brew in a fridge or at room temperature. However, the brew time should be adjusted accordingly. As colder water extracts the coffee slower, you will need to let it steep for longer if you are brewing in the fridge. In contrast, brewing at room temperature will require less time. We usually recommend extra 3 hours if you make cold brew in the fridge.