Here on INeedCoffee, we have several coffee brewing tutorials for making cold brew coffee. You can buy a Primula, a Toddy, or a cold brew filter pouch. Or maybe you don’t need a dedicated coffee brewer at all. That is what we decided to find out. We wanted to repurpose one of our existing brewers to make cold brew coffee. The perfect choice was the French Press.
For this article, we are using a 34-ounce French Press. The model we used for this article is no longer available for sale, but other models should work the same.
The basics of cold brew coffee are explained in the article Cold Brew Coffee is Not Rocket Science. Let water steep over coffee grounds at room temperature for 12+ hours then filter and serve. Let’s get brewing.
#1 Measure Coffee
How much coffee should you use? The answer to this question will vary depending on whom you ask. The short answer is more than you would for regular brewed coffee. If you do not want to deal with math or scales, just double the amount of the coffee you normally use when making hot French Press coffee. If you want to jump into the math, read on, otherwise skip ahead to Step #2.
In our French Press tutorial, we use a 17 to 1 ratio. This means 17 parts water to 1 part coffee. For cold brew, the advice is to use between 3 to 1 and 7 to 1. We found a 7 to 1 ratio was ideal for the French Press due to volume limitations. If you find 7 to 1 is not strong enough, I would extend the brew time by a few hours instead of adding more coffee.
The sizes of French Press brewers are an interesting topic. There is the size listed on the box, how much liquid it holds filled to the very top, and then the estimated coffee yield when you brew the coffee. Seattle Coffee Gear did a comprehensive test of these numbers in the post Coffee Presses: Overall Volume vs. Actual Yield. What you notice when you scan this chart is that the actual yield of brewed coffee is always a few ounces less than the volume listed on the box. The difference is the coffee grounds and the amount of water lost.
The more coffee added to a French Press, the more space the coffee occupies and the more water is trapped in the grounds at the end of a brewing cycle. As it shows in the Seattle Coffee Gear article, when we use a regular hot French Press we can expect to lose a few ounces. For cold brew, we will lose more, so it is advised to use a large French Press for making cold brew coffee. Smaller French Presses might not be worth the hassle because they yield so little. And unlike hot French Press, we aren’t ready to brew again in 4 minutes. We are waiting for another 12 hours.
We used a 34-ounce French Press for these tests. For easy math, I’m going to round this to 1000 grams. I did three brew cycles each at a different strength ratio. My goal was to keep the brew weights close and not fill it to the very top.
- Regular 17 to 1: 809 grams water + 48 grams ground coffee = 857 grams brew weight. Brew Yield = 733 grams (or 26 ounces)
- Strong 12 to 1: 800 grams water + 67 grams ground coffee = 867 grams brew weight. Brew Yield = 686 grams (or 24 ounces)
- Cold 7 to 1: 756 grams water + 107 grams ground coffee = 864 grams brew weight. brew Yield = 588 grams (or 21 ounces)
As you can see as we increase the strength of the brewing ratio, we see a decline in coffee yield. Using the same math, we would expect a 20-ounce French Press to yield 13.5 ounces of cold brew.
#2 Grind Coffee
You can use a medium to a coarse ground when brewing cold brew coffee in a French Press. We used a more coarse grind, but either will work. If you find the coarse ground cold brew is too weak, tighten up your grind. If the medium grind is too strong, you can either add more water or loosen up the grind.
See our Coffee Grind Chart to view the range between Medium Coarse and Extra Coarse.
#3 Add Ground Coffee and Water to French Press
Just like you would for a regular French Press, add the ground coffee to the bottom of the brewer. Only this time instead of hot water off boiling, you will add room temperature or cold water. Filtered water is ideal.
For this brew, we went Extra Coarse. Your grind does not need to be this coarse.
Add room temperature water.
#4 Gently and Slowly Stir
You want to make sure all the coffee grounds are making contact with water. Stir the coffee slowly. Try and cover as many grounds with water as you can.
Gently stir the coffee.
#5 Cover and Set Aside for 12+ hours
You can cover the French Press however you like. A small plate or plastic wrap are two ideas. You could use the French Press filter, just make sure you only press down enough to hold it in place. You do not want to press the filter down until the brew is finished, which is still 12+ hours away.
There is a debate on if you should cold brew the coffee on the counter or in the refrigerator. Either is fine. I prefer the counter as I think it brews faster, which means that if I need to cut the brew cycle short by an hour I can. However, if I was going to be away for much longer than 12 hours, I’d brew it in the refrigerator.
Peeking at the cold brew prior to pressing the filter down.
#6 End Brew and Serve
This trick also works great for regular French Press. By SLOWLY pushing the plunger down, you get a cleaner-tasting French Press. Strive for a 30-second plunge. At this point, you can transfer the coffee to a mason jar for storage or serve it up.
Not every grinder is awesome, so you might have some fine coffee particles that make it into your cup. If you experience this, you can filter the coffee again. Place a paper coffee filter over a jar and slowly pour the coffee. This will catch any loose grounds.
You can pour it into your spare French Press as well.
#7 Clean Up
The clean-up for cold brew French Press is the same as for regular brew French Press. Put the grounds in compost or save them for your garden.
If you have limited space for your coffee gear, it is good to know that the French Press can do double duty as both a hot and a cold coffee brewer. But to be honest, I found the yield to not be worth the effort and the cleanup was more work than a dedicated cold brewer. If you do have space and the budget for a cold brewer, check out the Penguin.
Make Concentrated Cold Brew Coffee With the Penguin Coffee – INeedCoffee tutorial on a dedicated cold brewer.
Coffee Brewing Guide – A collection of coffee brewing tutorials on INeedCoffee.
French Press Photos – Original photos used in this article.
Brewing photos by Joseph Robertson of Extracted Magazine, a digital coffee magazine published for iOS and Android.