The happiness of summer is probably being able to drink a cup of cold brew coffee that can relieve the heat without leaving your home, with the air conditioner blowing on. Due to the simple preparation method, even those who don't know how to make coffee can easily make an iced coffee that tastes mellow and smooth, has a rich and full flavor, and is clean and refreshing overall, making it suitable for summer tasting.
Different from common iced Pour over(V60) coffee and iced Americano, the entire extraction process of cold brew coffee uses low-temperature extraction method. Hand-brewed coffee and Americano coffee are extracted at high temperatures and then have a higher concentration of coffee liquid, and then ice cubes are added for cooling and dilution.
In a coffee bean, coffee flavor only accounts for 30% of the whole, and the remaining 70% is the wood fiber structure. And this 30% flavor does not need to be completely extracted, because more than 10% of it is bitter substances. Proper extraction of bitter substances can bring appropriate body to the coffee and increase the body of the coffee itself. Coffee lacking bitter substances will have a thin taste, while coffee with too much bitter substances will taste dry and astringent. We only need to extract 18%-22% of the flavor of the coffee.
The advantage of high-temperature extraction is that the heat in the water can promote the movement of water molecules and extract the flavor molecules from the coffee particles in a short time. However, the disadvantage is that if the water temperature and the grinding degree of the coffee particles are not controlled during brewing, the bitter molecules in the coffee can easily be over-extracted, resulting in varying degrees of bitterness in the coffee.
Low-temperature extraction will promote the movement of water molecules because there is no heat. At the same time, low temperature can effectively inhibit the release of bitter molecules. However, due to the low temperature, the flavor extraction time of coffee will also be relatively prolonged. It usually takes 6-12 hours to extract the sweet and sour substances more completely. Therefore, coffee extracted at low temperature usually only has a full sour and sweet taste. However, if the soaking time exceeds 12 hours, the wood fibers will also release the flavor of tree roots due to the long soaking. Although these flavors are not bitter, they will affect the overall aroma performance.
If you want the flavor of cold brew coffee to be released more completely, the coffee particles used should be slightly coarser than the coffee beans used for hand brewing. For example: the thickness of FrontStreet Coffee's Ethiopian Oiran coffee beans used for hand brewing requires a Chinese No. 20 standard sieve with an 80% screening rate, so the thickness used for cold brew coffee requires a 75% screening rate.
Why do you want to increase the concentration of cold brew coffee when you want to increase the grind size?
FrontStreet Coffee has discovered in many cold brewing operations in the past that the coffee powder will clump (clump) during the steeping process when Pour over(V60) coffee powder is used. So the same coffee beans, the same soaking time, and the same environment were used for static extraction, and different scales were used for extraction. The concentration difference between the two was compared through experiments. The results of the experiment showed that the concentration of coarsely ground coffee powder in a delicate and low-temperature environment will be higher.
This is because when the temperature of the water is close to normal temperature/zero for extraction, the movement of the molecules will also be reduced/zero. Without the thermal motion of molecules and the attraction between solid molecules to compete, the coffee particles will "clump", that is, agglomerate. So when the coffee is ground finer, the clumping will become larger, so that the coffee powder in the middle of the group cannot be fully extracted.
To make cold brew coffee, you usually only need to prepare a clean, oil-free, sealable container and materials for filtering the coffee (coffee filter paper/tea bag/high-density filter/cloth bag, etc.), then mix the coffee powder and ice water evenly and put it in the refrigerator to rest for 8-12 hours. FrontStreet Coffee recommends using 30g of coffee powder and extracting it at a powder-to-water ratio of 1:13 (that is, 30g of coffee powder is soaked in about 400g of water). After the extraction is complete, filter out the coffee grounds and enjoy.
The coffee beans used for making cold brew coffee, FrontStreet Coffee uses coffee beans with stronger sweetness and sourness/flavor.
For example, lighter roasted coffee beans from Africa and Central and South America: Ethiopian coffee beans sold in FrontStreet Coffee storesFront Street Oiran Coffee Bean(berry juice flavor),Front Street Panama Butterfly Gesha Natural Blend Coffee Bean(scented tea),Front Street Costa Mozart Coffee Beans(preserved fruit tone) are very suitable for making cold brew coffee.
Or specially processed coffee beans, such as Ethiopian Front Street Dorothy coffee beans (white peach oolong flavor) sold in FrontStreet Coffee stores, Front Street Columbia Rose Valley coffee beans (fruit liqueur chocolate flavor),Front Street Honduran Sherry Barrel Fermented Coffee Beans(wine flavored vanilla cream tonality) etc.
But if you usually like rich black coffee, you might as well try darker roasted beans, such as Front Street Indonesia PWN Golden Mandheling, Front Street Brazilian Queen Manor Yellow Bourbon, Front Street Papua New Guinea Bird of Paradise Coffee, etc. that are often on the Front Street bean list. The cold brew coffee produced by this type of coffee tends to have a rich tonality of nuts, caramel, and spices, and the aftertaste will be sweet with dark chocolate.
Tips for making cold brew
In many high-temperature brewing conditions, fresh roasting is often the first factor that many people consider. Firstly, the aroma of beans that are not in the tasting period will be greatly reduced. This is a consensus that everyone has reached. Secondly, the discharge of gas allows us to intuitively judge whether the beans are fresh or not, such as the concentrated oil in Italian and the bulge during steaming. It also shows that the coffee is at the peak aroma stage.
As the coffee beans continue to be heated in the boiler, the freshly roasted beans contain a large amount of carbon dioxide. If you want to extract the aromatic compounds inside, they must be discharged first. Cold brew itself is a relatively static extraction state, and low-temperature water inhibits the release of this part of gas to a certain extent, so the brewed coffee will easily become weak over time. Therefore, Front Street recommends using coffee beans with a roasting date of more than 10 days to make cold brew, which is more conducive to making coffee with rich aroma.
Professional coffee knowledge exchange. For more coffee bean information, please follow Coffee Workshop (WeChat public account cafe_style)
For more specialty coffee beans, please add FrontStreet Coffee on private WeChat, WeChat ID: qjcoffeex
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
