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Home » How To Make Cold Brew Coffee in a mason jar

How To Make Cold Brew Coffee in a mason jar

Do you love the cold, refreshing kick of tasty, non-acidic coffee on a hot summer’s mid-morning? Of course you do. Who doesn’t!?

Would you like to be able to make some without spending any money on fancy equipment…or without spending $10 on a ‘bespoke small batch’ bottle that you know has been made by marketers? Would you like it to taste better than when you pour your leftover hot coffee over ice? Yeah, that’d be great. My coffee sucks when I do that.

Here’s the thing; you probably have more mason jars in your house than you know what to do with, huh? Good, because today I’m going to help you make some delicious mason jar cold brew.

But First: Why Cold Brew?

Cold brew is the process of brewing coffee without hot water. Instead, you use room temperature or even cold water to do the job.

The actual brew takes much longer since you are not using hot water (think 12-24 hours instead of 3-5 minutes). The grounds and the water sit together in a container, slowly extracting over time. The result of brewing coffee this way is a smooth cup of coffee without all the acid (1).

Cold brew coffee has less acid in it per ounce as compared to hot coffee… This happens because coffee grounds, or more specifically the various oils, acids, and other aromatic molecules, are most easily extracted at about 195-205 degrees.

The process of brewing coffee cold is made easier by specifically designed brewers. With any of these, you can make more cold brew at one time. They come with everything you need, including a filter that will take care of even the tiniest grounds that slip by DIY filters.

But having a fancy cold brewer isn’t necessary. If you would like to test the waters of cold brew with what you already have in your kitchen, read on.

RELATED: If you want to learn more about the nuances of cold brew coffee: read this ultimate guide. You can also make cold brew with a French Press, or with an Aeropress – the only limit is your imagination.

The Steps: How To Make Cold Brew Coffee In A Mason Jar

Cold brew is so easy to make. All you need are a few kitchen basics and some patience. Below we have the written version, and here we have Scott show you on our YouTube channel:

Once we grind our coffee, we are going to simply put it in the jar and add water. We will let it sit for 12-24 hours and then strain out the larger grounds with a mesh strainer. Then we’ll pour it through a paper or cloth filter to get all the micro grounds out. Voila, we’ve got cold brew!

Now, it’s a little more complicated, but that’s the basic idea. Again, using an actual cold brewing device will save some time on the backend, as you won’t have as many steps. You also can’t make too much cold brew (unless you have a really big jar).

Everything you need to make cold brew coffee in a mason jar
Get your items ready to brew!

What You Need:

  • 57 grams coffee – Can’t make cold brew coffee without, well, coffee.
  • It needs to be coarse ground.
  • 475 ml room temperature water – We will make enough for about 2 cups of cold brew. If you have a larger mason jar, feel free to double or even triple this recipe to make more.
  • Coffee grinder* – Grinding your coffee fresh is super important for any coffee brewing that you do. A good burr grinder will get you consistent grounds every time – but you need one that can grind super coarse*
  • Scale – We’re going to weigh our coffee and water for the best results.
  • Mason jar – Make sure it’s clean and doesn’t smell weird (sometimes if they’ve been sealed shut for a long period of time, they smell funny. Wash them out so that smell doesn’t affect the coffee).
  • Paddle or spoon.
  • Mesh strainer – failing that; a cheesecloth, nut milk bag or some other type of cloth filter (I used a microfiber kitchen towel)
  • Paper filter – You can use any type of filter you have, a pour over filter, coffee pot filter, Aeropress filter.

*PRO TIP: Not all standard grinders can grind coarse enough for cold brew. If yours can’t – take your beans to a coffee shop and ask them to grind for you – Super coarse.

Step By Step Instructions

You’ll probably slap me for writing a whole article on this topic when you see how simple this really is. But do you know what? I enjoyed writing this article, and you seem to be still reading. Follow these steps if you want to make some kickarse DIY cold brew.

1. Weigh out 57 grams of your suitable beans.

Set a cup on your scale and tare it. Add 57 grams whole bean coffee. You can use any coffee you like, but light roasted beans will produce the best results. Here’s a guide to choosing beans for cold brew.

Weigh your beans for mason jar cold brew
ALWAYS measure your coffee. Aim for 57 grams.

PRO TIP: Cold brew is extremely forgiving. That means that you don’t necessarily have to use the freshest coffee. You can use the coffee that’s 3 or 4 weeks old, and it will still taste great.

2. Grind the coffee very coarse

Grind more coarse than a French press, or about the size of bread crumbs. Add it to the mason jar. Check out or coffee grind size chart here if you need some guidance.

coarse ground coffee
Here’s what your grounds should like like…more or less.

PRO TIP: If the grounds are too fine, the coffee will be over extracted. On top of that, it will be harder to filter out the grounds at the end.

3. Add Water and Give Her A GOOD Stir.

Pour your room temperature water into the jar. Using your paddle or spoon, give the grounds a gentle stir, ensuring all grounds are wet. Actually give her a good stir. You want all areas of the ground to be wet.

Adding water in a cold brew coffee
You ARE using high quality water to brew your coffee, aren’t you?

PRO TIP: If your water doesn’t taste great by itself, it isn’t going to make great coffee. Use water that tastes good and consider brewing with water like this for the best extraction.

4. Let it chill for 12 – 24 hours.

The longer, the stronger. The more time the water has to extract the coffee, the stronger the final cup will be. Again, don’t let it steep more than that, or you run the risk of getting very bitter coffee. 24 hours max. Don’t overdo it (2).

Personally, 16 hours is the sweet spot for my tastebuds. But the beauty of this process is you can do what you want and it will adjust the flavour. The first time you try it, aim for 16 hours, then next time add or minus 2 hours and taste the difference.

PRO TIP: Make 2 batches of cold brew at the same time. Let one steep for 12 hours and 1 for 24 hours, if you can. Do everything else the exact same and decide what tastes better to you.

5. Strain the coffee.

Set a mesh strainer on top of an empty container. Once the coffee has finished steeping, take your jar and pour it into the strainer. Empty these grounds in the trash. If you feel like getting pedantic (me), strain it multiple times. Our cold brew is almost ready!

Straining out large grounds with metal strainer
Straining: part 1

6. Now strain it again, using a paper filter.

Now, set up any coffee brewing device with a paper filter over your mason jar from earlier. This can be any paper filter you have on hand. Take the cold brew concentrate and pour it into the paper filter. The concentrate will slowly drip through the paper. It may take a while since the liquid is not hot (I like using the Aeropress because you can force the coffee through the filter much faster).

Don’t forget to wash your filter with warm water first. If you don’t do this, you may get a slight papery taste in your final brew.

Coffee Pouring into paper filter
Straining: part 2

Alternatively, use a cloth filter. If you don’t want to filter the coffee twice, or if you don’t have either a mesh strainer or a paper filter of some sorts, you probably at least have a towel you can use. I’d recommend using a cheesecloth or nut milk bag if you have one, but a kitchen towel will do (make sure it’s clean and probably dark in colour as the coffee will stain it).

Strain with cloth for mason jar cold brew
Straining: part 3!

Set the cloth on top of a wide bowl. Pour the contents of the jar into the cloth, fold up the corners and squeeze all the coffee out of the cloth. You now have a coffee concentrate and a dirty towel. Proceed.

7. Dilute the concentrate.

Add room temperature water to your concentrate. We recommend starting with a 1:2 ratio of coffee to water. So if you have 30 ml of coffee concentrate, add 60 ml water. Adjust to taste. More water if it’s too strong for your liking, less if you like it strong.

Pouring water in a mason jar
Turning the cold brew concentrate into a smoother glass of cold brew.

PRO TIP: The concentrate will last up to 2 weeks in the fridge. But if you add water to it, the shelf life decreases to 2-3 days.

8. Add ice and start sipping.

Now simply enjoy your cold brew coffee. Mason jars are perfect for drinking from as well.

add ice - the last step for making cold brew coffee in a mason jar
Sprinkling coffee beans next to your drink is completely optional.

PRO TIP: Take this concentrate with you camping, on road trips, or any other trip where you want to have all the supplies necessary to make a normal cup of coffee. Simply add water and ice to it when you are ready to drink it.

Final Thoughts

There you have it. Even with a mason jar and some other basic kitchen essentials, you have what it takes to make great cold brew. You no longer have an excuse to pour your leftover morning coffee over ice. Life’s too short. Drink better coffee.

Did you appreciate this tutorial? Now it’s your turn. Go make some mason jar cold brew and let us know how it tastes. We would love to hear from you in the comments below.

  1. Miller, K. Is Cold Brew Coffee Better for You Than Regular Coffee? (2016, December) Retrieved from https://www.huffpost.com/entry/is-cold-brew-coffee-bette_b_8964244
  2. Wolczynski, B. Cold Brew FAQs (2017, June) Retrieved from https://www.stumptowncoffee.com/blogs/news/cold-brewing-faqs

Alex Azoury
Alex is an Editor of Home Grounds, who considers himself as a traveling coffee fanatic. He is passionate about brewing amazing coffee while in obscure locations, and teaching others to do the same.

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