What's the Ideal Cold Brew Coffee Ratio, Grind Size, and Time? A Guide to Cold Brew Methods, Principles, and Flavor Profile

As June arrives and temperatures begin to rise, our friends in southern regions report they can barely stay outdoors for two minutes. During such hot weather, nothing beats a refreshing glass of iced coffee, and among all options, cold brew coffee remains the essential choice that must be enjoyed every year.

What is Cold Brew Coffee?

Cold brew coffee, known in English as Cold Brew Coffee, is made by steeping ground coffee beans in cold water for more than 8 hours, then filtering out the coffee grounds through appropriate equipment. The cold brew process is remarkably simple—with the right parameters, you can easily create delicious iced coffee. So how should you select key parameters like grind size and coffee-to-water ratio?

Grind Size

Since cold brew coffee uses cold water for extraction, the extraction efficiency is extremely low. In other words, you don't need to worry about over-extraction. Compared to pour-over coffee, you can choose a slightly finer grind size. Aim for an 85% pass-through rate with a #20 standard sieve, with minimal fine powders being ideal.

FrontStreet Coffee has discovered through testing that excessive fine powders not only lengthen filtration time but also result in more oils and fine particles floating on the coffee surface even after filtering, which affects the mouthfeel.

Coffee-to-Water Ratio

So how much water should be used for steeping? According to FrontStreet Coffee's production standard, the ratio of coffee to water to ice is 1:8:4, which translates to an actual coffee-to-water ratio of 1:12. Ice is added to ensure the water temperature remains sufficiently low, maintaining stable extraction efficiency.

Temperature

Cold brew coffee typically requires low-temperature extraction in a refrigerator. When extracting at low temperatures, the steeping time needs to be 24 hours. But can cold brew coffee be extracted at room temperature? Cold brew coffee can certainly be extracted at room temperature, though this corresponds to a shorter extraction time. However, FrontStreet Coffee recommends limiting the extraction time to 8-12 hours when using room temperature extraction.

How FrontStreet Coffee Makes Cold Brew Coffee

Cold brew is a very accessible brewing method. FrontStreet Coffee's cold brew recipe uses 50 grams of coffee grounds as the base, with a grind size achieving an 85% pass-through rate on a #20 standard sieve. Place the coffee grounds in a glass jar, then add 400ml of room temperature water and 200 grams of hard ice cubes (totaling 600 grams of ice-water mixture), creating a 1:12 coffee-to-water ratio. Stir the coffee grounds and water thoroughly with a stir bar, then seal and place in the refrigerator.

After 12-24 hours in the refrigerator, use filter paper to remove the coffee grounds and obtain clean coffee liquid. Then transfer the coffee liquid to a clean, sealed container and refrigerate for approximately 4 hours before serving.

In reality, compared to the strict parameters of other coffee extraction methods, cold brew offers great compatibility. From bean selection to the sealed container used, to the coffee-to-water ratio, grind size, and steeping duration—there's significant room for adjustment. In other words, as long as you avoid extremely extreme parameter combinations, you can produce excellent iced coffee.

However, some enthusiasts encounter problems despite using the same coffee beans and "copying" the parameters exactly—their homemade cold brew lacks the richness and sweetness of what they drink in the store. Why is this? FrontStreet Coffee has identified several key details that home brewers should check to see if these might be causing issues.

Steeping Time Should Not Be Less Than 8 Hours or Exceed 18 Hours

In pour-over coffee, we pay special attention to water temperature and time because water, as the primary brewing medium, directly affects extraction efficiency. Too high or too low temperatures will alter the coffee's taste. Since cold brew only contacts low-temperature water (4-10°C) throughout the process, extraction is very slow, requiring extended steeping time to release more aromatic compounds and allow fuller extraction of sugars and organic acids. This results in more balanced acidity, sweetness, and body. Generally, cold brew steeping time should be controlled between 8-18 hours.

FrontStreet Coffee once conducted a cold brew experiment using time as the variable, steeping one coffee for 6 hours, 10 hours, 16 hours, and 24 hours respectively. The results showed that the 6-hour brew was too thin in body with muted aromatics, while the 24-hour brew was distinctly bitter with signs of over-extraction. The 10-hour and 16-hour batches performed best, offering rich aromatics and full body.

Too Fresh Coffee Beans Can Also Affect Extraction

In many high-temperature brewing methods, freshly roasted beans are often the first consideration. This is because beans past their prime period lose significant aroma—a consensus already reached by many. Additionally, gas release allows us to visually judge freshness, such as the crema in espresso or the blooming during pour-over, which also indicates the coffee is at its aromatic peak.

As coffee beans continuously heat in the roaster, freshly roasted beans contain high amounts of carbon dioxide. To extract the internal aromatic compounds, these gases must first be released. Cold brew itself is a relatively static extraction process, and cold water to some extent inhibits the release of these gases, which can result in flat-tasting coffee. Therefore, FrontStreet Coffee recommends using coffee beans roasted more than 10 days ago for cold brew, as this helps produce more aromatic coffee.

Stir Thoroughly Both Before and After Extraction

Many beginners, eager to save time, simply add water, seal the container, and place it directly in the refrigerator. While the coffee surface may appear wet, some areas haven't actually contacted water, meaning these dry portions obviously don't participate in extraction. Additionally, after overnight steeping, most particles settle at the container bottom. If poured directly for filtering, you'll likely only get the lighter-colored upper layer, which probably won't taste good.

Based on FrontStreet Coffee's experience, if using a large-capacity pot, stir the coffee grounds and water thoroughly with a stir bar or long spoon before refrigerating. After removing from the refrigerator, stir again a few times before filtering. If using a sealed water bottle, simply shake gently up and down after sealing.

Filter Coffee Grounds Thoroughly for Better Cold Brew Taste

There are many equipment options for filtering coffee grounds, such as built-in cold brew pot filters, metal mesh filters, paper filters, and flannel filter cloths. Different pore structures naturally block different sizes of particles effectively.

Taking FrontStreet Coffee's cold brew pot as an example, its filter mesh has a 245-mesh size, which is considered quite fine, but fine and ultra-fine particles still pass through. Without secondary filtration, a layer of flocculent oil sheen floats on the surface. The coffee flavor differs little from filtered versions, but the rough sensation left on the tongue when swallowing is more noticeable, with visible sediment settling at the bottom of the cup.

For a better tasting experience, FrontStreet Coffee uses higher-density paper filters for an additional pass, which not only effectively removes ultra-fine coffee particles but also blocks over 80% of oils. After filtering out the grounds, FrontStreet Coffee also places the cold brew liquid in a sealed container in the refrigerator for 3-4 hours, allowing flavor compounds to further settle and mature. This results in exceptionally full-flavored cold brew with clearer mouthfeel and more vibrant acidity.

For more specialty coffee beans, please add FrontStreet Coffee on WeChat: ID: kaixinguoguo0925

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473