How to adjust the flavor baking without changing the baking degree has anything to do with the flavor?

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Today we're going to talk about energy, and from that perspective we're going to look at how to make baking adjustments.

energy

Energy, which in ancient Greek means "activity, operation," is an indirectly observed physical quantity seen as the ability of one physical system to do work on another. Work is defined as the spatial cumulative effect of a force displacing a body in the direction of the force and is equal to the product of the force and the displacement passed in the direction of the force.

The total energy contained in a body is based on its total mass, and energy, like mass, is neither created nor destroyed out of thin air. Energy is scalar, just like mass. In the International System of Units (SI), the unit of energy is the joule, but other units are sometimes used, such as kilowatt hours and kilocalories, which are also units of work. Energy is a uniform measure of the magnitude of motion of all matter.

(From Baidu Encyclopedia)

The essence of baking

From the above, we can know that coffee roasting is essentially energy transfer, coffee beans obtain energy from boilers and heated air, resulting in a series of physical and chemical changes, and the energy in this is carried out in the form of heat. Energy enters the coffee bean, all molecules will move because of the energy obtained, the decomposition of large molecules, the polymerization of small molecules, the change of color and volume of coffee beans, are all a game played by energy.

The heating process of raw beans is the heat conduction process of the air in the boiler and furnace. The heat conduction of objects is due to the existence of energy difference. The low temperature of raw beans means that the energy contained is small, so the heat energy will be transmitted from the boiler to the raw beans, resulting in the heating of raw beans. There is only one case of their transfer, that is, the energy difference, the raw beans heat up, because the outside temperature is higher, this process is irreversible, that is, heat can only run from high to low.

one explosion exothermic

We all agree with the idea that "one explosion releases heat", but from the above theory, it seems a bit wrong: one explosion of coffee beans compared to the boiler who has more energy? And if the coffee bean is heating the boiler, is it losing its own energy, that is, is it cooling down?

Obviously, the boiler's energy must be higher than that of coffee beans, and coffee beans do not heat themselves up while outputting energy. Here we want to think of coffee beans as a complex of water and coffee bean tissue separately. During the roasting process, the water absorbs energy and the temperature rises, finally reaching the boiling point to form steam, and the volume increases a lot, and the coffee bean tissue prevents these steam from expanding, so the internal pressure of the bean continues to rise, and finally the soft bean tissue cannot prevent the steam from escaping, breaking through the coffee bean fiber tissue and taking away energy, while the bean fiber continues to absorb energy. The characteristic is that the temperature rise rate at the beginning of the explosion drops sharply, and the wind temperature rises, which is the essence of heat release.

With the steam carrying a lot of energy, the roasting environment changes rapidly, which is easy to cause out of control. This requires opening the damper or reducing the firepower to stabilize the energy balance in the boiler. However, don't forget that the coffee bean tissue still needs energy to react. Therefore, it is necessary to predict the wind temperature and energy consumption to supplement the firepower, otherwise there will be a loss of temperature.

The essence of baking adjustment

Here we introduce the term AUC (Area-Under-Curve) for coffee roasting: surface means to calculate the area under the temperature curve of the bean and is intended to represent the energy used during roasting. If we want to adjust flavor without changing roast time or coffee roast, we need AUC.

examples

The following is the curve diagram of Yangjia 600g semi-hot air baking machine we use (flower butterfly)

Butterfly A is the baseline roast that we think is the best flavor, while B is the contrast roast.

It can be seen that the temperature of the beans, the temperature of the beans and the baking time of the two furnaces are the same, but the AUC of the B curve is less than that of the A curve (the area between the two curves is the energy difference), that is to say, the coffee energy of the B furnace is less than that of the A furnace, which leads to its flavor development is lower than that of the A furnace (as mentioned above, the molecules in the coffee receive less energy, and the reaction is less).

So when we look at the baking curve and expect that the energy supply is insufficient, we can increase the fire power to supplement the part of the energy that is less absorbed, so as to achieve the same degree of baking, adjust the baking. For example, curve C, we add fire in the front part to make the temperature rise, and then the brown point reduces the fire to make the temperature rise level to achieve the total energy absorption unchanged, so as to achieve the purpose of adjusting the flavor without changing the baking degree.

After adjustment, the C curve flower butterfly has the same high quality aroma and flavor as the baseline, and because it absorbs more energy than A in the peak period of Mena reaction (starting at 150℃), the enzyme flavor (flower aroma) is more obvious.

Of course, there is another way to adjust, is to extend the baking time of B to make the overall AUC similar, but this will affect the baking degree, so we will not discuss it today.

Finally, coffee roasting is a job of finding the optimal solution in order to best show the regional flavor characteristics of coffee beans, in which there are quite a number of parameters that can be adjusted and complex, a perfect work may be accidental, but it is very difficult to perfect every batch, because "a line difference, a thousand miles". I hope all the boiler workers who are addicted to coffee beans can get what they want ~

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