For more knowledge about specialty coffee, please pay attention to: Front Street Coffee (Frontsteet Coffee）
The thickness of the grind in coffee will directly affect the contact area between coffee and water and the extraction time of coffee. It will directly affect the taste of coffee. But at the same time, the grinding degree of coffee is also the biggest headache for many people! This article will talk about how to determine the grinding thickness of different coffee beans.
First of all, we need to make sure that the single-origin coffee beans or espresso blend coffee beans we buy are freshly roasted!
When buying single-origin coffee beans or espresso beans, we must buy coffee beans with a one-way degassing valve on the package and the roasting date of the coffee beans. The "one-way exhaust valve" (a small button-shaped hole on the top of the coffee bag) is designed to allow the coffee beans to discharge naturally occurring carbon dioxide while blocking other outside gases from entering the package. Each package of coffee beans from FrontStreet Coffee is freshly roasted and packaged with a one-way exhaust valve.
After buying coffee beans, we can check the roasting date, because coffee beans will produce a large amount of carbon dioxide in the coffee beans during the roasting process, so we have to give 3-7 days for the beans to self-emit carbon dioxide, which is commonly known as raising beans. If we directly brew the freshly roasted coffee beans, a large amount of carbon dioxide will be continuously emitted during the brewing process, which will make the entire extraction process very unstable. So how long will it last? Front Street recommends growing medium-light roasted coffee beans for 3-4 days, and medium-dark roasted coffee beans for 4-5 days.
As mentioned earlier, the most direct manifestation of the freshness of coffee beans is the carbon dioxide emissions of coffee beans. In addition to carbon dioxide, the freshness of coffee beans determines the aromatic substances of coffee flavor and aroma. These small molecule aromatic substances evaporate faster than the large molecule substances that reflect the bitterness of coffee, so the stale coffee beans have less carbon dioxide and aromatic substances, so there are fewer substances that can be extracted. If the coffee beans are no longer fresh, grinding them will not help.
How does the size of coffee grind affect the flavor of coffee?
1. For the same number of grams, if the grinding degree is fine, the number of times it needs to be cut increases, the surface area increases, and the area where water can contact the coffee powder increases.
2. The finer the grinding degree, the finer the coffee powder is cut into. The shorter the distance from the surface of the coffee powder particles to the center of the coffee powder particles. The shorter the time for water to reach the inner part of the coffee powder particles for extraction/the easier it is to extract coffee flavor substances.
To put it simply, when other parameters are the same, the finer the particles, the higher the extraction rate. The finer the coffee powder is ground, the larger the contact area with water, and the higher the concentration of dissolved coffee. On the contrary, the coarser the coffee is ground, the smaller the contact surface area with water, and the lower the concentration of coffee extracted.
What are the consequences of grinding coffee too finely?
Judging from the appearance of the particles, the particle size is smaller. At the same time, because the particles are smaller, the distance between the particles is shorter, and it is more difficult for the water flow to pass through them, so the drip filtering time is longer during the brewing process. Finer grinding results in smaller coffee powder particles. The surface area of the coffee particles increases, and the area where the water flow can extract coffee substances increases, so the concentration and extraction rate increase. The coffee tastes rich, bitter and astringent, and the other flavors are masked.
What will happen if the coffee is ground too coarsely?
Judging from the appearance of the particles, the particle size is larger. At the same time, because the particles are larger, the distance between the particles is larger, and the water flow is easier to pass through the coffee powder, so the filtration time is shorter during the brewing process. Coarse grinding results in larger coffee powder particles. The surface area of the coffee particles is reduced, and the places where the water flow can extract coffee substances are reduced, so the concentration and extraction rate are also reduced. The coffee tastes bland, light in taste, and has almost no flavor.
How do we determine coffee grind size?
Front Street here recommends that you use a No. 20 mesh (mesh size 0.85mm) to measure the grinding degree.Correction. Then use 10g of coffee beans for a rough grinding and then pour them into the sieve for sieving. After sieving completely, see how much coffee powder falls out of the tray under the sieve. Use the pass rate to correct the grinding degree. FrontStreet Coffee (FrontStreet Coffee) grinding thickness standard sieve pass rate: ice drip > hand brew Psiphon 80% > Mocha American drip filter 75-80% > cupping 70-75% > French pressure 65-70%.
Of course, for coffee beans with different roasting degrees, the corresponding grinding degrees used are also different. For example, the grinding degree for light roasted coffee brewed in Front Street is a grinding with a 0.85mm diameter screen pass rate of 80-85%. Medium roast coffee will be ground with a 0.85mm diameter screen pass rate of 70%-75%. Dark roasted coffee will use a 0.85mm diameter screen with a pass rate of 65%-70%. However, everyone has different requirements for the richness of coffee. These data are for your reference only. You can still make different adjustments according to your own taste.
What should I do if I don’t want to buy a coffee bean grinding correction screen? !
Front Street knows that such a round of operation is quite troublesome. Here Front Street has made a small summary of the grinding degree of coffee powder to see what rough grinding degree is used for the beans of his coffee brewing tools. Front Street divides the thickness of coffee powder into five types: very fine powder, fine powder, medium fine powder, medium powder, and coarse powder.
(From left to right: coarse powder, fine powder, very fine powder)
Very fine powder: suitable for making espresso coffee (moka pot, espresso machine)
When making espresso, the coffee powder must be pressed hard to create resistance to the high-pressure hot water, so that the essence of the coffee can be truly extracted. The more uniform and fine the grinding, the tighter the packed coffee powder will be, which can produce balanced resistance to water. The "squeezed" espresso that comes out in this way will have rich coffee oil.
Fine powder: suitable for making hanging ear coffee
This coarse and fine grinding is the "soul partner" for Front Street's hanging ear coffee. The main reason is that the entire hanging ear is made of filter paper, which produces a large amount of water. Unlike hand brewing, which has a closing position, such as the commonly used three-hole filter cup now, it actually slows down the flow of water, so the hanging ear needs more fine powder to increase the extraction area and extract more substances.
Medium-fine powder: suitable for brewing medium-light roasted coffee (all kinds of Pour over(V60) coffee filter cups), we recommend Front Street Guo Dingding, Front Street Oiran, Front Street Geisha, Front Street Strawberry Candy
When Front Street brews medium-light roasted coffee beans, they use medium-fine powder, which is about the size of fine sugar, and the grinding degree is between 75% and 80% of the sifting rate. Because medium-light roasted coffee beans generally have rich acidity, medium-fine powder grinding can improve the overall sour and sweet performance of coffee~
Medium powder: Suitable for brewing medium-dark roasted coffee (all kinds of Pour over(V60) coffee filter cups), we recommend Front Street Jamaica Blue Mountain, Front Street Golden Mandheling, and Front Street Cymbidium
When Front Street brews medium-dark roasted coffee beans, they use medium powder, which is about the size of coarse sugar, and the grinding degree is between 70% and 75% of the sifting rate. Medium powder is not easy to produce extremely fine powder, nor is it easy to over-extract the coffee due to unstable water flow control at the beginning, causing large amounts of water to accumulate on the filter cup and soaking the coffee powder.
Coarse powder: suitable for making coffee with a French press
The French press extracts the original taste of coffee by soaking it for 4 minutes. Compared with Pour over(V60) coffee, the coffee liquid will be turbid. The reason is that when filtering through a metal filter, the pore size is larger, so we have to use coarse powder for grinding. First, the flavor of the coffee is slowly extracted, but when the French press presses the filter, the coffee powder will not "run out" through the gaps in the filter and mix with the coffee, affecting the taste when tasting.
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
