Step-by-Step Guide: How to Make Cold Brew Coffee at Home - Cold Brew Coffee Recipe Ratios and Process

What Cold Brew Really Is

At its core, cold brew is simply extraction at low temperature. Under cold conditions, the small molecules responsible for aroma and acidity dissolve into the water more readily, so the resulting cup tends to taste light, with sweetness and bright acidity taking the lead. Cold brew also has almost no barrier to entry: no special gear or dedicated space required. At home, a bottle, some water, and a refrigerator are enough to keep yourself supplied with coffee whenever you want it.

In practice, cold brew is remarkably forgiving. Pick beans you actually like, use sensible parameters, and you can practically brew a good batch with your eyes closed. After all, the method boils down to mixing ground coffee with water and leaving it in the fridge to steep.

The Three Parameters That Decide Everything

Most disappointing batches of cold brew come down to one thing: the parameters were off. To make a genuinely good batch, you only need to get three numbers right — grind size, ratio, and time.

Grind Size

Grind size sets the total surface area of the coffee. The larger that surface area, the faster water can reach the interior of each particle and pull out flavor. Because cold brew is a long, still immersion, a finer grind helps the flavor compounds dissolve more completely. In practice, grind a little finer than you would for pour-over.

Coffee-to-Water Ratio

The coffee-to-water ratio sets how strong the final coffee will be. A common complaint is that homemade cold brew tastes watery, and the usual cause is simply too little coffee relative to the water — too much water dilutes the concentration.

This is why it pays to brew a little stronger than you think you need. If the concentrate turns out too intense, you can always dilute it with ice. If it comes out too weak, there is no easy fix — you cannot simply "reduce the sauce" the way you would in cooking. So at the start, err on the side of a higher coffee-to-water ratio rather than drowning the grounds in water.

Steeping Time

The last parameter to watch is time. Since cold brew extracts by steeping, the duration decides how much material ends up in the cup. If you want the strongest possible concentrate, extend the steep accordingly.

With those three points clear, we can move on to the actual process.

How to Make Cold Brew Coffee at Home

Start by choosing beans that match what you want from the cup. For cold brew that is full of juicy, sweet, and pleasant character, go with a lightly roasted coffee. If you want flavors that are distinct and pronounced, choose beans that went through deeper fermentation during processing. And if you prefer a heavier mouthfeel, reach for a medium-dark to dark roast. (With a dark roast, try adding a small amount of osmanthus — the result is unexpectedly delicious.)

For this batch, FrontStreet Coffee selected "Mozart," a bean that has been especially popular with shop customers recently. Cold-brewed, it delivers a full, juicy body with notes of grapes, berries, and red wine, plus a purple floral character reminiscent of lavender.

Mozart Cold Brew Parameters

Coffee: 80g (adjust to your own consumption needs)
Grind setting: Ek43 setting 9, roughly 85% passing a #20 sieve, a texture like fine sugar
Coffee-to-water ratio: 1:10
Steeping time: 12 hours

Have a sealable container ready. Once the beans are ground, the first step is to tip the grounds into the container.

Then pour in the target amount of water. Since FrontStreet Coffee uses 80g of ground coffee, that means 800ml of room-temperature water.

Give it a quick stir so the grounds wet evenly and faster.

Seal the bottle and put it in the refrigerator to steep.

When the steeping time is up, take it out and filter off the grounds with filter paper. Your cold brew is ready to drink — and if you brewed a strong concentrate, remember to dilute it with ice.

FrontStreet Coffee Recommendation

Cold brew flatters floral and fruity beans, so lightly roasted, aromatic coffees shine here. For a floral, ice-coffee-friendly option, the FrontStreet Sun-Dried Huakui from Ethiopia is a natural fit: sun drying lets the beans absorb the sweet aromatics of the fruit and pulp, and steeped cold it shows notes of magnolia, cream strawberry, dried mango, guava, and black tea.

If you want a juicy, fruit-forward cup, try the FrontStreet Kenya Cherry Tomato. Its sweet-sour profile of cherry tomato, snow pear, black plum, and smoked plum comes through beautifully at low temperature, with low bitterness and a full acidity that turns especially refreshing over ice. It is grown in Kenya's Thika region from the SL28 and SL34 varieties and processed with the local K72 double-washed method, then given a medium-light roast to build out its complex fruit character.

For a more budget-friendly everyday concentrate, cold brew uses a lot of coffee, so an affordable, tasty blend makes sense. The FrontStreet Strawberry Candy combines a classic Panama Gesha — offering delicate rose and orange — with a Costa Rican honey-processed coffee that brings grapes, dried blueberries, and a strawberry-gummy sweetness. The layers stay lively and bright in cold brew, and if you let it settle a while longer, it takes on a wine-like fruitiness.