Coffee review

How to heat cold coffee? Is the hand-brewed coffee good for the second time?

Published: 2024-07-14 Author:
Last Updated: 2024/07/14, Temperature, an old topic in coffee circles, is almost inseparable from a suitable temperature zone, from the storage and baking of raw beans to the extraction and taste of ripe beans. Even if you are not in the habit of brewing coffee, you must always be told to drink it while it is hot. The implication is that after the coffee gets cold

Temperature, an old topic in coffee circles, is almost inseparable from a suitable temperature zone, from the storage and baking of raw beans to the extraction and taste of ripe beans.

Even if you are not in the habit of brewing coffee, you must always be told to drink coffee while it is hot. The implication is that the coffee will not taste good when it gets cold. But now it is winter, an inadvertently hot coffee becomes cold in the twinkling of an eye, and one can't help but shudder with a sip, let alone finish the whole cup. At this time, many friends who do not want to waste will find a way to heat up the coffee again, so how to heat it up?

There has been an article on Qianjie for everyone to popularize science, coffee from hot to cold, mainly from two aspects: one is the aroma, the other is the taste. The freshly brewed coffee has been volatilizing its own aroma in the process of cooling. When the coffee fully tends to room temperature, most of the aroma of the high temperature has dissipated, which naturally does not taste so good.

And, as the temperature drops, coffee weakens our taste buds' perception of sweet, sweet and other tastes, and accordingly, the perception of sour and bitter tastes will become more obvious. So a cup of deep-roasted coffee usually becomes "more bitter" when it is cooled, while a cup of light-roasted coffee with less bitter substances tends to be "more sour" after cooling.

It is precisely because this is an irreversible flavor change process that the reheated coffee should not be as delicious as it was when it was first brewed. Since the coffee flavor can not be completely "revived", then as much as possible to "preserve" more aroma substances, is our primary purpose of reheating coffee.

Here in Qianjie, a less complicated comparative experiment is designed, that is, two types of coffee beans with different flavors are cooked by hand extraction, and then they are naturally cooled to room temperature, and then sampled with an electric stove, alcohol lamp, and the steam bars of the Italian coffee machine are reheated, and the taste differences are compared.

Coffee beans: Panamanian Flower Butterfly & Qianjie 2013 Yunnan small Iron Card Powder quantity: 30g Powder / Water ratio: 1:15 Water temperature: 93 ℃ & 90 ℃ filter Cup: V60 Grinding degree: EK43s scale 10 three-stage Water injection: 50g, 200g, 200g

Tasting Panamanian Flower Butterfly Coffee at different stages has just been brewed (70 degrees): lively citrus acidity, with light floral aromas and honey sweetness, tastes like a cup of clear green tea with bright acidity.

Cool to room temperature (28 degrees): in front of the street, the liquid of this pot of butterfly coffee becomes a little turbid, tasting mainly with a sense of tea, weak acid and no obvious aroma.

Taste the flavor of Qianjie Tieka coffee in different periods

Freshly brewed (68 degrees): coffee is hot with sweet aromas of chocolate, nuts, roasted sweet potatoes and toffee, with a touch of dark berry acidity and a good mellow feel.

Cool to room temperature (28 degrees): the texture of the coffee becomes thick, the entrance is still nutty, without the round sweetness of the heat, and with a hint of wood. After swallowing, there is still an unfriendly tail rhyme in the mouth, reminiscent of walnut skin-like dryness, but not lasting.

Next, two pots of coffee were sampled and heated in three forms until they reached 50 ℃, and the tasting experience of each group was recorded one by one.

Electric heater group: the heated butterfly tastes like the acid of berries and citrus peel, and the taste slightly sinks, but there is no negative flavor; another pot of Qianjie iron skin card is heating up again, although it also maintains some nutty tones, but there are also some low acidity, which is more abrupt.

Alcohol lamp group: when the two pots of coffee were heated to 50 ℃, the flavor performance was not as rich as that when the coffee was flushed, but the increase in temperature did improve the taste of the coffee, with sour, sweet, bitter and round texture.

Steam bar group: the two cups of coffee have almost lost the rich aroma of warm time, the acidity and bitterness are not high, but the taste has become a little "water", the concentration also has the feeling of being diluted. Qianjie guessed that this change was mainly due to the fact that when heated with a steam bar, the high-temperature water vapor emitted from the holes was sprayed directly into the coffee liquid, thus causing the coffee to become "water".

It can be seen that, to some extent, reheating coffee with external heat sources such as direct fire can not restore the original rich aroma, but it can effectively reduce the bad drinking experience caused by the cooling of coffee and make the coffee more palatable. Of course, in addition to the heating methods mentioned in the front street, you can also try other ways to improve the cold coffee, such as the microwave oven.


Front Street Cafe

No. 10 Baoqian street, Yandun road, Dongshankou, Yuexiu district, Guangzhou, Guangdong province