The decay and defects of coffee aroma

Fragrance, only fragrance, is the highest value of coffee. The lack of aroma in the coffee is like a lack of flavor. Cymbals can have different forms and portions, and fragrances have different components and presentation.

Coffee that loses its fragrance always makes people feel defective. The main reason for the fragrance of the coffee is its aroma.

Through this article, we will look at the possible causes of the taste or loss of taste of coffee.

In the past, we have repeatedly mentioned that the quality factor of a cup of coffee comes from four important stages, namely:

1. Coffee shop management: including varieties, planting conditions and weather conditions, fertilization, irrigation, disease prevention and control, etc.

two。 Post-harvest processing methods: including collection methods, post-collection preservation, post-processing methods, cleaning and hygiene of the processing site, drying methods, storage methods and environment, and cleaning process. And then there is Jun Cheng.

3. Baking method: including the understanding, operation and preservation of roasted coffee beans.

4. Make coffee.

That is to say, coffee products are being shaped in all the above stages, and at the same time, coffee products may have defects as a result of improper operation.

The following are the key points mentioned in the Coffee Cup Tester handbook, which is about the time when coffee bean aroma spoils and defects are produced, and it is worth considering by our coffee workers:

The first paragraph occurs during harvest and drying.

When farmers make coffee fruit or coffee beans dry, it will affect the aroma of coffee beans, and the most important thing is to cause rotten smell.

When the coffee is harvested, if the fruit is left in the coffee bar for too long, the bad taste in the coffee will continue to produce, and the enzymes inside the fruit will begin to break down the dough. As a result of chemistry, arabica coffee beans produce "Rioy" and robusta is "rubbery". During the dry period, if the coffee fruit is actually placed in a high and rich environment, the action of enzymes in the interior will be accelerated, producing a "fermented flavor" (fermented). This is why the peeling should be done within a few days after the coffee is harvested, or the peeling should be carried out within 24 hours, so as not to pile it up for too long.)

In general, coffee beans are laid on the concrete floor, or on a high drying bed, or on a plastic cloth. The main purpose is to keep the shops clean and dry so as to avoid pollution. If the coffee beans are placed in a dry place, especially when the soil is dry, the oil inside the beans absorbs the smell of the soil and produces a "earthy". If you put the coffee beans in the moisture mixture, it is easy to cause mildew and produce a "mildew smell" (musty). If the machine is used to dry, when the drying speed is too fast, the oil inside the beans will decompose and produce "skin odor" (hidy). (Xianming: it feels as if mildew occurs slowly. As a matter of fact, due to the environmental tide or being drenched by Rain Water, coffee beans get moldy very fast. in about 1-2 days, you can see the appearance of mildew. As a matter of fact, by the time you see this mildew, it has been going on for some time.)

The second stage occurs in the Tibetan section, which is the aging stage of coffee beans.

This is the period between harvest and drying until baking. In the first few months after harvest and processing, the coffee beans had a special smell of grass, like the taste of new harvest alfalfa, known as "grass" (grassy). The enzymes in the interior of raw beans continued to function, and after two months, this flavor decreased gradually. Until you scold the gully? E? Squeeze Q is "new bean" (new crop), that is, "season bean". (Ming Ming: the new bean finished by the harvest has its own characteristics and its unavoidable smell of green. This is also the reason why foreign beans are not in a hurry to sell after they are collected and disposed of. Is to reduce the smell of green.)

Under proper storage conditions, coffee beans will slow down the action of enzymes. About a year later, these chemical reactions began to affect the acidity in the interior of coffee beans. The taste shows that this kind of coffee beans are already "past crop". If raw beans are stored for more than 20 years, the enzyme acts a lot to reduce the content of various acids, this kind of coffee beans is called "old beans or aged beans" (aged).

In addition to the effect of enzymes, coffee beans lose slowly and produce a hay-like "strawy" step by step. Over the years, coffee beans continue to lose organic matter, and eventually produce an acceptable "woody".

When the third stage occurs during baking, it is mainly coking.

When the roasting degree reaches 400 ℉ (204 ℃), the continuous production of sugar in the coffee bean is biochemical: it combines with the organic and non-organic substances inside the coffee bean to form brown caramel. The sugar content in the inner part of raw beans increases, which will affect the contents of fragrant peas.

If the degree is not enough, so that the coking process is not adequate, the roasted coffee beans will have a grassy taste. Vanilla is like the green bean (green peas) in green vegetables, known as "stinky green" (green). If the cooking process is too slow, the roasted coffee beans will taste dull and tasteless, so they will be called "baked". If the baking speed is too fast-- the coffee beans are clearly scorched-- the chemistry is not yet completely changed, forming a "tipped". If the temperature is too high, the surface of the coffee beans will be scorched, resulting in a "scorched smell" (scorched).

After the fourth stage is roasted, the coffee beans will run out.

After the coffee beans have been roasted, they begin to have an excretory effect. At this time, the latest coffee beans, filled with flavors, most of them are sporadic mercaptan, or sulfur compounds. After the coffee beans are ground into powder, a lot of flavor will be lost.

As the discharge process continues, more sporadic organic compounds are water-soluble aromatic mixtures in the presence of carbon dioxide, which will be lost due to the release of carbon dioxide. The loss of this kind of spice causes the "flat" of coffee beans. Coffee beans continue to drain, and sporadic organic substances continue to discharge, resulting in "tasteless beans" (vapid).

If water and oxygen are added to the coffee beans, it will make the taste more dilute. First of all, the oil inside the coffee beans will produce bio-oxidation. The taste of coffee comes from the shadow, resulting in a "light taste" (insipid). Then, continued exposure to oxygen and moisture will accelerate the oxidation of linoleic acid and triglyceride, producing an unpleasant flavor, which is called "acid failure" (stale). Finally, the oil in the inside of coffee beans interacts with oxygen and water, resulting in a tasty taste, called "oil smell" (rancid).

The fifth paragraph is after the bubble. After the coffee is brewed, the fragrance of the coffee melts faster than that of the other stages. After the coffee has been brewed, it begins with the most "fresh" (fresh), that is, the content of the organic substances that make up the coffee flavor is the most abundant. If the foam liquid in an unsealed container holds water, the role of active molecules is high, which makes the loss of the substance faster. After brewing, the coffee first loses its flavor and becomes "flat". Continue to add food to make the volatile substances evaporate, and the coffee becomes "vapid". Prolonging the extension time will affect the preservation of organic substances in the coffee liquid. Long-term organic compounds split into short ones, which will increase the acidic taste, which is called "sour taste" (acerbic). Coffee contains chloric acid. Secondly, due to the evaporation of water, the moisture content in the solution is correspondingly increased, resulting in a "briny". If you continue to add it, the egg whites are scorched and the coffee liquid becomes hot, and there will be a "tar flavor" (tarry). Finally, the bitterness of asparagus in the coffee solution increases, and its bitterness is added to show a "brackish" (sweet taste).

As shown in the fifth paragraph above, we can know how to make coffee. Or it can be answered by some people: "can you brew coffee twice?" that is to say, the second time. " What's the answer? it depends on what kind of coffee you want to make for yourself and your guests.

-- reference information: Ted R. Lingle "The basics of Cupping Coffee"--

1. Necessary equipment for coffee parsing: 1). Clean water: do not use contaminated water. Do not use steamed water and processed water. 2)。 Coffee spoon: you can use a spoon or magnetic spoon instead. 3)。 Glass or magnetic cup with a capacity of 150 tons: three cups are prepared for each copy. 4)。 Coffee tray: one plastic tray is prepared for each coffee shop. 5)。 Coffee spoon: a deeper coffee spoon for sipping and mixing coffee. 6)。 Record the table. 7)。 Coffee beans.

2. Coffee analysis method.

Coffee Cupping: tasting coffee, also known as coffee product analysis, coffee cup.

Coffee tasting is a method to systematically analyze the aroma and taste of coffee by using standard brewing and tasting steps.

Tasting methods usually rely on the smell, taste, and oral sensation of the product.

1)。 Prepare for copy

Soak the coffee directly in water and do not use other agents (such as lemonade). The agent will remove the fragrance or put it away.

The taste (like the taste of rice) goes into the coffee. Put 7.25 grams of fresh coffee powder into a magnetic cup or glass.

Pour about 90-96 ℃ water into the coffee powder in the cup. The coffee powder will surface and after soaking

Will sink one by one. After 3-5 minutes, stir-fry the coffee powder floating on it, mix it well with water, and sink to

The bottom of the cup. Scoop out the coffee powder that has not sunk to the bottom of the cup. Note that clean water free of chlorine and other chemicals must be used to avoid smelling. A cup of coffee contains

99% water.

2)。 Feeling and feeling

When tasting coffee, in order to stimulate God, the actions of sipping, sipping, and swallowing should be very careful.

Coffee products are composed of six steps: analyzing the aroma, aroma, taste, smell, taste, and degree of coffee.

a. Sweet potato Fragrance

Pour the sample of the fresh coffee powder into the cup, and after the fresh coffee beans are ground into powder, the carbon dioxide on the noodles will turn it.

Let out some sweet smells and try your best to taste them. The characteristics of incense show the essence of the taste. Sweet means sour taste, thorn

The nose indicates an irritating smell. The strength of spice corresponds to the new strength of the sample from baking and grinding to picking.

b. Fragrance Aroma

Pour the boiling water into the coffee pad in the cup. Coffee powder will float on the surface and do not soak for three minutes. Mix with a coffee spoon

The coffee powder floating on it, at the same time, suck up the air released by the coffee powder with its nose deep and long. It tastes like fruit.

, grass, to drupe aromas. The smell is the same as that of coffee beans. The fragrance strength has something to do with the new strength of the original.

c. Taste Taste

Use a coffee spoon to scoop 6-8 tablespoons of coffee liquid, close to your lips, and sip the coffee liquid quickly and vigorously to make the coffee full.

On the surface of the tongue, the taste buds are completely stimulated by sweet, bitter, sour and bitter tastes. How do you feel about it?

In response, different sensory positions show different characteristics. For example, alcohol reduces the sweetness of sugar and makes the tip of the tongue feel first.

I feel the tingling of sour coffee. Hold the coffee in your mouth for 3-5 seconds, pay attention to the strength of its taste, and find out different tastes.

d. Smell Nose

Step four and step three go hand in hand. Suck the coffee into the mouth, leave it empty, pass through the tongue, and have something to eat.

The effect of transpiration changed from liquid state to steady state. Strengthen the absorption action to introduce this body into the nasal cavity, taste and smell at the same time.

The special fragrance works. According to the standard roasting degree, we can sense the caramelization of coffee beans according to different conditions.

Like nut, caramel, chocolate. For deep-baked rice, there are pine flavor, spice flavor, and carbon flavor.

e. Pharynx Aftertaste

After drinking the brewed coffee for a second, the throat swallows a small part of it, causing the water vapor to pass quickly.

The back of the neck goes into the nasal cavity. It will leave a sweet smell like chocolate, or even the smell of fire or grass. It's possible.

Like the pungent smell of cloves or turpentine, or even a combination of these flavors.

f. Degree Body

Finally, explore the taste of the coffee liquid. The tongue fluttered across the mouth. The oil in the coffee will feel smooth.

. Albumen will show a sense of stickiness. The degree of coffee is made up of these two senses.

After the coffee sample is bought, focus on the three steps of taste, smell and taste. Recharge in different ways

The shadow of meekness. After the coffee is gone, you can get a more accurate effect by tasting the coffee for the second time. Coffee tasting is usually used.

In comparing two different coffee products. So that the coffee drinker can accurately distinguish the difference between the two kinds of coffee. As such, Ben

For a long time, you usually spit the coffee liquid into another cup without swallowing it. Rinse your mouth with a small amount of water to give you a clear taste.

After that, then try the next cost.

The results are listed in the Coffee Analysis Checklist.

SCAA raw bean classification (The SCAA (Speciality Coffee Association of America) Green Coffee Classification): this system pays more attention to the relationship between defective beans and coffee products in the cup than other systems. According to this system, take 300 grams of properly cooked coffee beans and roast them under web headings 14, 15, 16, 17 and 18. The coffee beans left on each bowl are weighed and recorded. Generally speaking, in order to save time and convenient calculation, 100 grams of coffee beans are used as the same unit. But in order to be more accurate, if the coffee bean product is higher than the average, it will cost 3000 grams. If the quality is below average, or if there are obvious deficiencies, only 100 grams.) It is special after baking and steaming. It is divided into the following categories:

Selected Speciality Grade (Grade 1): there can be no more than five defective beans in 300g sample beans. There can be no important flaws. Allow a maximum of 5% difference in the number of networks. There is at least one special expression in degree, fragrance, aroma, or acidity. And there are no deficiencies and pollution. No quaker beans. The water content is between 9-13%.

[*] quality Premium Grade (Grade2): no more than eight defective beans can be found in 300g sample beans. There can be no important flaws. Allow a maximum of 5% difference in the number of networks. There is at least one special expression in degree, fragrance, aroma, or acidity. And there is no shortage, there are only three quaker beans. The water content is between 9-13%.

[*] Exchange grade (Grade 3): there are 9-23 defective beans in 300g sample beans. Beans above heading 15 account for at least 50% of the total weight, while beans below heading 14 account for less than 5%. There can be no defects in the mug. Up to 5 quaker beans. The water content is between 9-13%.

[*] below standard Below standard grade (Grade 4): there are 24-48 defective beans in 300g sample beans.

[*] Off Grade (Grade 4): there were more than 86 defective beans in 300g sample beans.

Main flaw

Secondary flaw

Item

Eye

Is equivalent to a

Complete flaw

Number of occurrences of

Item

Eye

Is equivalent to a

Complete flaw

Number of occurrences of

All black

one

Soya bean

2-3

Total fermentation

one

Bean paste / peel

2-3

Be honest / fruitful

one

Rupture / chip

five

Oishi

two

Damage

2-5

Zhong Shizhong

five

Local black

2-3

Dazhiwu

two

Partial fermentation

2-3

Scutellaria nipponensis

five

Curdled object

five

Soya bean

five

Little Stonehenge

one

Tetranychus chinensis

one

Water spatula

2-5