What Details Should You Pay Attention to When Making Cold Brew? What's the Right Coffee Grind Size for Cold Brew? How Long Should You Steep It?

Mastering Cold Brew Coffee: Key Techniques for Perfect Home Brewing

With the arrival of summer, FrontStreet Coffee welcomes another peak season for iced coffee. If you prefer staying home but need to refresh yourself during this sleepy afternoon, making a delightful cold brew coffee at home is the perfect choice.

Different from regular hot water brewing, cold brew primarily involves mixing coffee grounds with cold water (room temperature), letting them steep in a low-temperature environment for several hours, and finally filtering out the grounds to obtain iced coffee concentrate. With just a bag of coffee, a sealed clean container, water, and a refrigerator, you can achieve cold brew freedom at home.

In reality, compared to other extraction methods with strict parameters, cold brew offers great compatibility. From coffee bean selection to sealed containers, and from grind ratio to extraction time, it allows for significant flexibility in adjustment. In other words, as long as you don't use extremely extreme parameter combinations, you can create delicious iced coffee.

However, some enthusiasts encounter problems during their attempts:明明采用的是同一款咖啡豆，参数也"照搬照抄"了，做出来的冷萃就是不如店里喝到的浓郁香甜，这是为何呢？这里前街总结出了几个关键的细节，居家的小伙伴不妨对应自查一下，看看问题是否出自这里。

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

In pour-over coffee brewing, we pay special attention to water temperature and time. Since water serves as the primary extraction medium, temperature directly affects extraction efficiency—too high or too low will alter the coffee's taste. Similarly, excessive time leads to over-extraction, while insufficient time may result in under-extraction. However, cold brew only contacts low-temperature water (4-10°C) throughout the process, resulting in very slow extraction efficiency. Therefore, extending the steeping time allows more aromatic compounds to be released, enabling fuller dissolution of sugars and organic acids. The resulting coffee achieves better balance in acidity, sweetness, and body. Generally, cold brew coffee steeping time is recommended to be controlled between 8-18 hours.

FrontStreet Coffee once conducted a time-variable cold brew experiment, steeping equal amounts of FrontStreet Coffee's Panama "Butterfly" coffee for 4 hours, 10 hours, 16 hours, and 24 hours respectively. The results showed that the 4-hour coffee had almost no aroma and tasted rather watery. The 24-hour cold brew had a slight bitterness with signs of over-extraction. The 10-hour and 16-hour groups showed the best flavor performance, with the former being relatively refreshing and the latter more concentrated.

If you're worried about forgetting the time, you can also refer to FrontStreet Coffee's "lazy person" approach: start steeping between 7-9 PM the previous evening, and filter it between 7-9 AM the next morning. This ensures the time stays within the conservative range of 10-14 hours.

2. Overly Fresh Coffee Beans Can Also Affect Extraction

In many high-temperature brewing methods, freshly roasted beans are often the first consideration for many people, as beans past their prime will have significantly diminished aroma—this has long been a consensus. Secondly, gas release allows us to visually judge the freshness of coffee beans, such as the crema in espresso or the blooming during the pour-over process, which also indicates that the coffee is at its peak aromatic stage.

Coffee beans continuously heated in the roaster contain large amounts of carbon dioxide immediately after roasting. To extract the internal aromatic compounds, these gases must first be released. Cold brew itself is a relatively static extraction state, and low-temperature water to some extent inhibits the release of these gases. As you can imagine, using "freshly roasted beans" for cold brew can easily result in under-extraction. If you're not in a hurry to drink, FrontStreet Coffee recommends choosing coffee with a roast date of more than 10 days ago for steeping, which is more conducive to creating richly aromatic cold brew.

3. Stir Thoroughly Before and After Extraction

Many beginners, in their haste, simply add water and immediately seal the container before placing it in the refrigerator. Although the surface of the coffee grounds may appear wet, some local areas may not have contacted water, and obviously, these dry parts of the coffee haven't participated in the extraction. Additionally, after a night of resting, most particulate matter settles at the bottom of the container. If you directly pour and filter at this point, you'll likely only get the light-colored liquid from the upper layer, which presumably won't taste very good. Therefore, the "stirring" action is essential when making cold brew.

Based on FrontStreet Coffee's experience, if you're using a larger container, you can use a stirring rod or a long spoon to thoroughly mix the coffee grounds and water before placing it in the refrigerator. After taking it out, stir a few more times before filtering. If you're using a sealed water bottle, simply shake it gently up and down after closing the lid.

4. Thoroughly Filter the Grounds for Better Cold Brew Texture

There are many options for filtering coffee grounds, such as the built-in filter screen of cold brew pots, metal filters, filter paper, flannel filter cloths, etc. Different filter pore structures can effectively block different particulate matter. Taking FrontStreet Coffee's cold brew pot as an example, the filter screen has a mesh size of 245, which is considered relatively fine, but there can still be fine and ultra-fine powder extraction. If not filtered again at this point, a layer of flocculent oil will float on the surface. The flavor of the coffee won't differ much from filtered coffee, but the rough sensation remaining on the tongue when swallowing will be obvious, and some visible powder will settle at the bottom of the cup after drinking.

For a better tasting experience, FrontStreet Coffee uses denser filter paper to sieve again, which not only effectively filters out ultra-fine powder but also blocks over 80% of condensed oils. After separating the grounds, FrontStreet Coffee also places the cold brew concentrate in a sealed container in the refrigerator for 3-4 hours, allowing the flavor compounds to further settle and mature. This way, the cold brew tastes full-bodied with a clearer texture and more transparent acidity.

FrontStreet Coffee (FrontStreet Coffee)
No. 10, Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473