Coffee roasting: coffee roasting firepower and throttle coffee roasting record sheet

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The key to baking is the regulation of firepower, according to the amount of heat, how to supply and other conditions, the baking results are also different. Because of this, the adjustment of firepower, like a veil, can only be done by experienced bakers, and some bakers even collect the skills of firepower regulation as a secret. and some bakers can't teach it to others because they can't explain why.

So based on the limited facts we know as the background, we can infer how to heat and how to adjust the firepower.

There is data to prove that when baking 1kg raw beans, the calorie required is about 470kJ, this data can only be measured in the laboratory, the general baking conditions can not be determined. To reflect this data, we can only set specific conditions to compare changes in the baking reaction, which can be inferred backwards.

According to the regulation of firepower, the temperature of beans will also change accordingly, and the process of change is called baking curve trend chart, or baking curve for short (Roasting Profile).

The baking time will change with the change of heat supply. But we don't know whether the baking time and heat are moderate. So we have to find a standard firepower to determine whether the heat is moderate or not.

The function of the throttle is not only to draw air to drive hot air to avoid smoldering and incomplete combustion, but also to adjust the flavor!

What is meant by adjusting flavor?

This has to imagine the state of the pot with regard to the opening and closing of the throttle. When the throttle is opened, the exhaust air volume increases, driving more air, and the proportion of hot air increases (the premise is the hot air of the full temperature). At this time, the amount of air driven will affect the efficiency of temperature absorption of raw beans, because in the process of heating, the air will be heated and expand, forming a greater pressure in the pot, and the positive pressure and negative pressure in the baking pot can be adjusted by the opening of the throttle. But this is a gradual and changing process, as if the locomotive without brakes is gradually accelerating on the gentle slope, but the speed can be adjusted by opening and closing the throttle, and the throttle is the role of the throttle.

When the speed of the natural advance is greater than the speed of the engine, controlling the throttle can adjust the speed of the locomotive. Although it is a bit of a mouthful, people who have ridden a bike should have experienced a similar situation. Low-grade accelerator can reduce the speed of the downhill. From this concept to look at the throttle, and the size of the throttle as the number of clutches, it will probably be more intuitive.

When the throttle is open, how much will it be first gear? Second gear? Third gear? N gear?

With the fire of the lighter close to the mouth of the sampling spoon, close the air door until the fire is stable, this state is regarded as a gear.

Open the throttle until the flame is slightly inhaled into the sampling spoon, which is regarded as the second gear.

The maximum bend of the opening of the sampling spoon from the opening of the throttle to the flame is regarded as the third gear. N gear is used as a heat engine, generally speaking, the roaster is heated to about 180 degrees by adjusting the medium fire, and the throttle is opened so that it will not heat up again. It is generally between 2 and 3 gear.

The change of the first gear is that when the air in the furnace expands, reaching 140 degrees, you can find silver skin and other fine shavings ejecting with the hot gas from the sampling mouth, and the pressure in the pot is greater than that of the outside world.

The change of the second gear is the air expansion in the furnace. It can be noticed that the silver skin will not be ejected from the mouth of the sampling spoon at about 150-160 degrees. At this time, the pressure in the pot will wait with the outside world.

The change of the third gear is that when the temperature in the furnace reaches an explosion density, it can be observed from the thermometer that the temperature rises slightly and steadily at about 180-200 degrees Celsius.