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The original intention of cold brew coffee is that under low temperature conditions, small molecular substances that tend to be aromatic and sour are more easily released in cold water, so the coffee tastes light and tastes sour and sweet. In addition, because it is not restricted by equipment or location, cold brew can be said to be coffee that is within reach of people. As long as you have the raw materials, bottles, water, and a refrigerator, you can easily achieve caffeine freedom at home.
Regarding the production of cold brew, someone asked Front Street: What is the difference between cold brew made with different proportions? What impact does the powder to water ratio have on coffee?
As a typical immersion extraction, cold brew coffee is a process in which low-temperature water and coffee powder are contacted in the same container for a long time to extract the flavor. When other parameters remain unchanged, the greater the proportion of water, the lower the concentration of the coffee liquid, the lighter the coffee flavor, and the thinner the taste; conversely, the smaller the proportion of water, the higher the concentration, the stronger the taste, and the thicker the mouthfeel.
Therefore, in order to find a balanced taste and give the coffee a better flavor, we have to apply an appropriate powder-to-water ratio.
How long does it take to brew cold brew? How finely does the coffee need to be ground?
We all know that the various parameters involved in any extraction scheme are more or less related. For cold extraction, the ratio of powder to water is not the only factor that determines the taste. We also look at the grinding thickness, soaking time, water quality, and the most critical coffee beans.
Although low-temperature extraction can reduce the appearance of bitter substances, it is not 100%. Therefore, if you want to pursue delicious taste, the coffee powder used for cold extraction should not be ground too finely, let alone soaked for too long. For the former, we recommend controlling the pass rate of the 0.85mm standard sieve to be in the range of about 80-85%, which should look like granulated sugar to the naked eye; for the latter, it is best to control it within 6 to 16 hours, because this ensures sufficient contact time between the powder and water, and it is also less likely to show negative taste due to over-extraction.
Regarding the selection of coffee beans, the Kenyan cherry tomatoes on the bean rack in Front Street here are used as an experimental demonstration. They use the K72 washing method and the varieties are SL28 and SL34. Both SL28 and SL34 are varieties selected after multiple breedings. SL28 belongs to the Bourbon genetic group and has the bright tone and rich acidity of the original Bourbon. The SL34 bloodline is closer to the Typica gene and the acidity is milder.
The iced coffee made from Kenya AA has the feeling of dark berries wrapping the mouth in the mouth, and also has the aroma of plump cherry tomatoes. It is very enjoyable to drink when iced, so it is the first choice of many friends for cold brew.
How does cold brew coffee made with different powder to water ratios taste?
Since cold extraction is always performed in an environment of 0 to 10°C, the extraction efficiency is very low. The coffee powder and water are in a relatively static state, and there is no external force in the process, so the speed at which the coffee powder dissolves flavor substances is very limited. In order to make the experimental results more clear, Front Street sets four more common powder-to-water ratios, namely 1:8, 1:10, 1:12, and 1:15. The other parameters remain unchanged.
The production process is all the same. Pour the coffee powder and water into the container in sequence, stir, seal, and put it in the refrigerator. When the time is up, we take it out and filter it (you can stir it once in the middle).
Coffee beans: Kenya·Small tomatoes
Powder amount: 18g
Soaking time: 6 hours
Grinding degree: fine sugar/China No. 20 standard sieve sieving rate 80% (EK43s scale 9.5 grid)
Powder to water ratio: 1:8, 1:10, 1:12, 1:15
Corresponding water volume: 144g, 180g, 216g, 270g
The coffee liquid with a powder to water ratio of 1:8 is the darkest in color, has the strongest and most sour taste, is even a little salty in taste, has only a little berry flavor, and has a bitter finish;
The coffee liquid with a powder-to-water ratio of 1:10 smells of sugarcane and has a flavor of red bouillon, berry, and pear tea. The taste is slightly strong, with high acidity and not obvious sweetness;
The cold brew with a pink to water ratio of 1:12 has the clearest taste, with flavors such as cherry tomatoes, red wine, plum juice, sugar cane, and the aftertaste of plum candy. The concentration is moderate and the sweetness and sourness are balanced;
The coffee liquid with a powder-to-water ratio of 1:15 is the lightest in color and has a thin body. It has only a little acidity of black tea and berries, and has a bland taste, but almost no bitterness.
It is not difficult to see from the above comparison that the ratio of 1:8 uses less water, so the coffee flavor does not have enough space to display, and it is easy to show the negative characteristics of being thick and bitter; on the contrary, the ratio of 1:15 uses more water, and the soluble substances are over-diluted, resulting in insufficient pure thickness of the coffee, and it naturally tastes bland and tasteless.
Among the two groups of 1:10 and 1:12, it is obvious that cold brew coffee made with 1:12 has the best flavor and taste when drunk directly. However, Front Street gives priority to 1:10 in many articles and daily products. Why is this?
Finally, in order to maintain the taste of cold brew at a low temperature, in addition to serving it in ice cups, Front Street usually also adds1～2Hard ice cubes are used, so that even if the coffee is diluted, the flavor will not be changed too much; secondly, since each customer has different taste preferences, some like light and some like strong, the coffee tastes full and thick when the ice cubes are first added, but slowly melts into water over time, and the coffee gradually becomes lighter. Therefore, using a high-concentration version of cold brew with ice satisfies both "heavy drinkers" and "light drinkers".
You can now buy the above coffee beans online at the Taobao store “FrontStreet Coffee” (前街咖啡). FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou, China, and its Guangzhou retail shop sells coffee beans only. The shop carries dozens of coffee beans from different origins around the world, including carefully selected single-origin beans for V60 pour-over and espresso. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers.
The FrontStreet 2013 Yunnan coffee beans sold in the store come from the Typica variety grown at FrontStreet Coffee’s own plantation in Yunnan. The name comes from the year the brand and the plantation were founded. You can buy these beans from China’s Yunnan origin at the Guangzhou shop and at FrontStreet’s Taobao store.
FrontStreet coffee beans are freshly roasted within 5 days and deliver consistently excellent quality and great value. Orders placed before 17:00 are shipped the same day, and most areas within Guangdong Province receive them the next day.
FrontStreet Coffee Taobao store: https://qianjiecoffee.taobao.com
Or search for “前街咖啡” (FrontStreet Coffee) on Taobao
Important Notice: FrontStreet Coffee has moved to a new address: 315, Donghua East Road, Guangzhou (coffee beans only)
Tel: 020 38364473
