Can Cold Brew Coffee Be Mixed with Milk?

Cold brew can be mixed with milk. The filtered cold brew tastes good on its own, and fresh milk softens the off-flavors that low-temperature extraction can bring out while adding roundness and a silkier body. The key is balancing coffee grounds, water, and milk so both the coffee aroma and the milky sweetness come through.

Bean selection, grind size, coffee-to-water ratio, and steeping time all shape the result. A common approach is to brew a concentrate before bed, refrigerate it overnight, filter out the grounds the next morning, then dilute with water or milk to taste. Drip bags offer a simple way to make cold brew at home.

In the scorching summer heat, iced coffee becomes a lifesaver for many, and cold brew (cold-pressed) firmly holds the top spot for homemade iced coffee thanks to its simple operation and smooth taste. But many people wonder: can the brewed cold brew be mixed with milk? The answer is yes, but to achieve both coffee aroma and milky fragrance, the ratio of coffee grounds, water, and milk must be just right. This article breaks down everything from bean selection for cold brew, grind size, coffee-to-water ratio, steeping time, to the golden ratio for adding fresh milk, and even includes a lazy hack for making cold brew with drip bags, so you can easily recreate a café-quality iced milk coffee at home.

Looking at the weather app on your phone, the high temperatures are all above thirty degrees—it seems this summer and the rolling heatwaves have truly arrived! Isn't it time for everyone to put all kinds of iced coffee on the agenda?

When it comes to the most popular category of homemade iced coffee, cold brew (also called cold-pressed) definitely holds a place. Brew a pot before bed, toss it in the fridge, and the next morning just filter out the grounds and drink it straight—it's simply a "lazy person's exclusive perk." However, a friend threw out a question: can the prepared cold brew be mixed with some milk?

After chatting, Front Street Coffee figured out that this friend doesn't have a coffee machine at home, but the first thing every morning is to gulp down a cup of iced coffee with milk. Among the many simple coffee methods, cold brew happens to be her best skill, but she wasn't sure how to add milk to the brewed coffee liquid to make it smooth.

So, can cold brew coffee actually be mixed with milk?

The answer is, of course: absolutely yes~ The filtered cold brew itself is delicious, and milk is also a good thing, so there's no problem putting the two together. Moreover, the addition of fresh milk not only softens the off-flavors that coffee grounds bring out during low-temperature extraction but also adds a touch of roundness and silkiness to the coffee, elevating the overall drinking experience.

However, to achieve a final product that has both the richness of coffee and the sweet aroma of milk, you need to find a harmonious ratio among coffee grounds, water, and milk.

How exactly do you add milk to cold brew coffee?

Actually, any coffee beans can be used for cold brew, but since iced coffee is all about that refreshing coolness and sweetness, light to medium roast beans are ideal. For home experimentation, you can buy cold brew beans like Front Street Coffee Strawberry Candy, Front Street Coffee Blackberry, and Mozart that extract rich floral and fruity notes; if you're not a fan of acidic coffee, try beans with prominent nutty tones like Front Street Coffee Bird of Paradise and Front Street Coffee Queen's Estate.

Since cold brew is completed at low temperatures, cold water extracts coffee grounds more slowly, and compared to hot water brewing, bitter compounds are less likely to come out, so in terms of grind size, coffee-to-water ratio, and steeping time, it's not as particular as pour-over. Usually, as long as you stay within a general range and choose the right beans, a few simple steps will yield a delicious cup of iced coffee.

Taking Front Street Coffee's daily cold brew as an example, the grind size is slightly finer than pour-over, which is a 75-80% pass rate through a Chinese No. 20 standard sieve—visually about the texture of fine granulated sugar. This corresponds to a 9.5-10 setting on the EK43s, and for a hand grinder like the C40, about 22-26 clicks.

Next, pour the ground coffee into a clean container—a dedicated cold brew pitcher works, or even a mineral water bottle. Add room-temperature water at a 1:10 coffee-to-water ratio, stir well, cover with plastic wrap, and steep in the fridge for at least 8 hours (12 hours is optimal). Finally, filter out the coffee grounds with filter paper, and the cold brew is ready.

The coffee-to-water ratio for cold brew is often the biggest concern. Front Street Coffee believes that if you plan to drink it straight without adding anything, you can use a 1:12 to 1:13 ratio, because black coffee made in this range has the best drinkability and releases its aroma well. But considering we'll be adding fresh milk in the end, we need to increase the coffee's concentration to avoid it being overly "diluted." Here, Front Street Coffee recommends using a 1:10 to 1:11 ratio for better results.

Finally, it's time to pour the milk.

To find the ideal taste ratio, Front Street Coffee took out two prepared cold brews from the fridge (Panama 90+ Geisha and Panama Elida Estate) and did a small test, adding ice milk to three equal portions of cold brew at ratios of 1:1, 1:0.8, and 1:0.6 (Front Street Coffee used Bright Fresh Pasture), meaning 100g of coffee liquid with 100g, 80g, and 60g of milk respectively.

The results showed that both coffees performed mediocrely in the first group, with the milk flavor overpowering the coffee, and almost no coffee aroma could be detected. The latter two groups had a more balanced taste. The 90+ Geisha, known for its fermented winey notes, performed best in the 1:0.8 group, while the Elida, with its fruity profile, shone in the 1:0.6 group.

Therefore, regarding the amount of fresh milk, Front Street Coffee suggests judging by the type of coffee beans used for cold brew: deep-roasted coffees with nutty and chocolate flavors are suitable for 1:1; beans with winey and cocoa notes can be mixed at 1:0.8; and cold brews made from acidic coffee beans like berries and citrus should be mixed with milk at a ratio of around 1:0.6.

No grinder? Drip coffee bags work too

In addition to the steps mentioned earlier, some clever friends have thought of using drip coffee bags to make cold brew, as long as you have a fridge at home. Besides the essential drip coffee, just prepare a cup with a lid and you can start right away.

The procedure is actually similar to the regular cold brew method, and you still need to pay attention to the ratio of coffee grounds, water, and milk. For specific steps, you can refer to the graphic tutorial published by Front Street Coffee. The only difference is that since the filter paper is replaced with a non-woven drip bag, the final filtering of the coffee liquid will take a bit longer, so you'll need a little more patience~

The above content is compiled by CoffeeHunters, a coffee news website.