What is the reason why hand steaming did not form a "hamburger"? Detailed introduction of steaming and water injection techniques

When brewing freshly baked coffee, watching the powder layer expand in hot water to form a round drum exhaust is a great pleasure for many hand players. When the powder layer does not prop up in the steaming stage, or even "sunk" down, we will wonder if there is something wrong, will this cup of coffee taste good?

Why does coffee powder form a "hamburger" when steaming? In the roasting process, the bean roaster provides a lot of heat for coffee beans, and the structure in the beans continues to expand, resulting in further opening of the stomata in the cell wall of raw beans, storing a large amount of carbon dioxide. As the roasting is complete and the coffee beans return to normal temperature, the carbon dioxide gas begins to be gradually discharged.

The most important purpose of steaming is to help coffee powder just release most of the carbon dioxide, while "awakening" the soluble substances in coffee in order to better handle various fragrant flavors in the future. The "hamburger" we see is the emission process of the gas in the coffee powder. The higher the drum bag is and the longer it lasts, the stronger the gas release. What are the reasons for not forming a drum bag when steaming? 1. Coffee beans are not fresh from the point of view of extraction, coffee beans contain carbon dioxide has both advantages and disadvantages. During daily storage, the rich gases in unground beans can hinder the volatilization of flavor substances, but in the process of brewing, these gases in the presence of water will prevent us from obtaining a variety of aroma components. At this time, steaming, an auxiliary extraction method, is very important. In general, the carbon dioxide gas contained in properly stored coffee beans will be discharged 40 to 50 days after baking. When the gas runs out, it will not form a "hamburger" when steaming, and the aroma substances will disappear together, so the coffee will be greatly reduced.

two。 When the grinding degree is too rough, the gap between the particles will become larger, and under the action of gravity, the injected hot water will flow into the next pot before it can penetrate into the coffee powder. If there is no water support between the particles, the gas will be discharged along the broken gap, and the whole powder layer will collapse.

This usually happens when replacing new beans, such as when the original grinding is suitable for medium and deep roasted coffee, and then replaced with anaerobic fermented beans (traditionally treated coffee beans with much greater fluffiness than similar roasting). Will be because the grinding is too thick so that there is no "hamburger". If you make coffee without a drum bag, drink "water" and the extraction time is less than 1 minute and 55 seconds. Qianjie suggests a little fine grinding (fine granulated sugar) to coordinate the extraction rate. 3. Did not wet all the coffee powder some friends pay too much attention to the amount of steaming water and time, but its water control ability still needs to be improved, after the injection of the first section of steaming water, there are powder particles are dry, so that the raised powder layer will be biased to one side, it is difficult to form a "solid drum bag", steaming is not thorough, the coffee that comes out is likely to be extracted unevenly. If it is impossible to fully soak the coffee powder in 2 times the amount of water, then inject a little more water (about 5 grams) to make sure that all the coffee powder is soaked and the gas can be discharged.

4. When we formulate a cooking plan, we will default to a steaming formula of "twice the amount of powder and water for 30 seconds", which is also a safer way to flush a strange bean. However, the flow control after picking up the hand flushing pot sometimes inevitably deviates from the plan, and the most common situation is to inadvertently inject too much water. Since the coffee powder can only absorb about twice its own weight of steaming liquid, the extra water will flow into the pot early along the edge of the filter cup, causing the drum to sink. Qianjie has experimentally compared that as long as the amount of water is controlled during steaming and the powder layer is evenly soaked, the direction and size of water injection around the circle do not have much effect on the extraction results. However, if the intensity of water injection is too strong, the water column directly impacts the particles of the local powder layer, and the emitted gas is more on one side and less on the other, so it is difficult for the powder layer to form a stable support surface, so it will collapse naturally.

Therefore, in order to achieve the ideal steaming drum bag, Qianjie recommends using a small amount of water (15g powder, the steaming water is controlled within 35g) and injecting water evenly and gently around the center, so that the coffee powder can be evenly soaked to form a round "hamburger" shape. 5. The baking degree is too shallow, and the drum bag formed is not obvious. due to the early baking time, the bean texture is hard and the gas content is less, so in the steaming stage, there is no obvious expansion, its performance is like stale coffee beans, and the gold foam produced by subsequent water injection is thin. But this does not affect its flavor. Some shallow roasted coffee beans also have a similar phenomenon, in steaming, coffee drum bag is not obvious, shallow micro-drum, this is also a normal phenomenon.