Content and Concentration of Caffeine in Coffee

• Coffee

Coffee is a drink made from roasted coffee beans. The main ingredients of coffee are caffeine, tannin, fat, acid fat, volatile fat, protein, sugar, fiber, minerals and so on. Drinking coffee is a double-edged sword. On the one hand, it promotes skin metabolism, activates the digestive organs, and has a hangover function. On the other hand, it aggravates high blood pressure and induces osteoporosis and affects sleep.

• Caffeine

Caffeine is a xanthine alkaloid compound. Pure caffeine is white, intensely bitter powder. Its chemical formula is C₈H₁₀N₄O₂, chemical name is 1,3,7-trimethylxanthine or 3,7-dihydro-1,3,7-trimethyl-1H-indole-2,6-dione, molecular weight is 194.19.

Figure1. Chemical structure of caffeine

• The Efficacy and Harm of Caffeine

Caffeine is a central nervous system stimulant that has an extensive stimulating effect on central nervous system. It can stimulate the cerebral cortex, increase the excitatory process of the cerebral cortex, restore mental vitality, reduce fatigue, eliminate drowsiness, and improve mental activity. In addition, it plays an active role in cardiovascular system, promoting acid secretion in stomach and treating diseases such as migraines. When the dose is increased or the vital center of the ventricle is suppressed, it can directly stimulate the respiratory center and the vascular movement center, thereby deepening breath and increasing blood pressure. There is also a weak excitatory heart and diuretic effect. However, excessive caffeine can be harmful. Excessive caffeine, usually more than 250 mg (equivalent to 2-3 cups of brewed coffee), can cause central nervous system overstrain. Symptoms of overexcited caffeine include restlessness, nervousness, excitement, sleeplessness, blushing, increased urine production, gastrointestinal dysfunction, muscle twitching, distraction, irregular or rapid heartbeat, and restlessness. High doses of caffeine can lead to death. In experimental rats, half of the lethal dose of caffeine was 192 mg/kg body weight. But the amount of caffeine in general that produces different effects depends on weight and personal sensitivity, which is about 150 to 200 mg per kilogram of body weight. About 140 to 180 cups of coffee are consumed by the average adult for a limited period of time, potentially leading to death. Although it's almost impossible to kill people by drinking regular coffee, there have been reports of deaths from overconsumption of coffee.

• The Amount of Caffeine in Coffee

The federal regulations governing the use of caffeine also establish a “tolerance” for manufacturers, who wish to add caffeine to their products. In fact, 21 Code of Federal Regulations section182.1180 (b) states that caffeine's tolerance is 0.02%. This means that any product manufactured with caffeine must have 0.02% or less will be considered safe. For example, a 12 oz drink can have 68 mg of caffeine and still meet the 0.02% limit. Different types of coffee have different amounts of caffeine. According to the U.S. department of agriculture, the average instant coffee has about 57 mg/1.8 g caffeine, the picture below shows the content of each ingredient in the best-selling coffee.

Figure 2. The content of each ingredient in the best-selling coffee

• Factors Affecting Caffeine Content and Concentration

While caffeine itself is a bit bitter, the taste of coffee is essentially independent of how much caffeine it contains. Therefore, the concentration and content of caffeine cannot be judged by the taste of coffee. Its concentration is mainly related to the mixing of coffee beans, extraction, grinding, roasting stage and water temperature.

• Recommended Daily Intake of Caffeine

Studies have shown that daily coffee intake of no more than 6 mg/kg will not have a negative impact on the human body. The daily intake should not be more than 360 mg for 60 kg person. If each cup of coffee is 236 mL (1.8 g instant coffee powder/serving), the caffeine content is 57 mg, then the maximum limit of instant coffee for one day is 6 cups. If you have caffeine from other sources: such as functional drinks, tea, and chocolate, then you should have fewer cups of coffee. Although coffee has a refreshing effect, you can not dependent on drinking a lot of coffee for a long time, which will cause harm to the body and have certain dependence. At the same time, everyone's sensitivity and tolerance to caffeine are different, so the specific situation varies from person to person.

• Related Regulations

1. § 182.1180 Caffeine

2. FDA Regulations for Caffeine

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