The most original purpose of coffee is to refresh you, whether it is an espresso you drink and go, an American drip coffee maker that is a fixture in the office, or even a pour-over single-origin coffee you go out of your way for, it all has a refreshing function. It is just that everyone chooses the right coffee according to different requirements for the setting, function and taste.

So then, with so many kinds of coffee, which coffee is the most refreshing to drink?

Why does drinking coffee keep you awake?

Coffee's refreshing effect comes mainly from caffeine. The reason we feel tired is that we have a substance in our body called adenosine that controls this. The longer we stay awake, the more adenosine accumulates in the body, and the easier it is to feel sleepy. Caffeine, however, can block adenosine from binding to the brain's nerves, so the brain, having received no "tiredness message from adenosine," keeps rallying its energy and carrying on working, which makes a person not feel tired (to translate it, you use caffeine to trick your brain).

So the most refreshing coffee is certainly coffee with a relatively high caffeine content. And the caffeine content in the final coffee mainly depends on the caffeine content of the coffee beans and the way the coffee is made. So Qianjie divides it into these two steps for discussion.

How much caffeine does a cup of coffee usually contain?

The release of caffeine is also related to time. Under the same high-temperature extraction, coffee extracted for a longer time has a higher caffeine content, so espresso-based coffee drinks are actually not the highest in caffeine. Pour-over drip coffee and French press immersion coffee have a higher caffeine content. And although cold brew and ice drip coffee are low-temperature extractions, the extremely long extraction time makes their caffeine content higher than all the previous ones.

Below, Qianjie provides some common coffee drinks' caffeine content references: (Note: all coffee beans are Arabica; cold brew and ice drip coffee are affected by extraction time, here based on ice drip 8 hours and cold brew 12 hours)

Making espresso uses 20g of Qianjie specialty blend coffee beans, extracting 40g of coffee liquid in 25-30 seconds, yielding about 100mg of caffeine; because double shots are used as the base, the caffeine content of drinks such as latte, Americano and cappuccino is the same as that of espresso.

In other words, whether it is a hot Americano or an iced Americano, since both have 40g of coffee liquid added, their caffeine content is the same, and they are equally refreshing after drinking.

If you use 15g of grounds to make pour-over coffee, brewing 195ml of coffee liquid, the caffeine is about 90mg; when using 20g of coffee grounds to make pour-over coffee, obtaining 260ml of coffee liquid, the caffeine becomes 120mg;

French press (20g grounds / 4 minutes): about 135mg;

Cold drip coffee (one glass, 20g grounds / 200ml coffee): about 135mg;

A glass of cold brew coffee uses 20g of Qianjie strawberry candy coffee grounds and yields 200ml of coffee liquid, so drinking one glass of cold brew means an intake of about 140mg of caffeine;

Drip bag coffee (one bag, 10g grounds / 120ml coffee): about 50mg;

Instant coffee (one bag): about 50mg.

How many cups of coffee can you drink at most in a day?

According to surveys, an adult's daily caffeine intake should not exceed 400mg, which means that in theory, as long as the intake stays below this amount, there is generally no problem! In other words, for Americano, no more than 4 cups a day is fine, and for cold brew, no more than 3 cups a day is fine.

But we should be aware that everyone has a different constitution, and tolerance to caffeine varies even more from person to person, so Qianjie recommends drinking coffee in moderation; if you experience symptoms such as palpitations, a racing heart or shortness of breath after drinking coffee, it is advisable to reduce your intake, or to stick to just one Americano or latte a day.