Soluble matter. Hot coffee and cold coffee how to make iced coffee

Soluble matter. It is these soluble substances that give the coffee mellow and delicious. The process of coffee extraction can effectively release these substances.

The brewing methods of coffee are mainly divided into two categories according to temperature and time:

1. Hot brewing coffee: when it comes to hot brewing coffee, we naturally think of dripping coffee made from an old-fashioned home coffee machine or hand filter pot. The making of this kind of coffee is very simple. All we have to do is pour hot water over the coffee powder. We can often have the classic drip coffee in the restaurant. But in the coffee shop, baristas use professional coffee machines to greatly increase the rate of coffee production. The espresso they make is more fragrant, sour and bitter.

two。 Cold brewed coffee: the easiest way to make cold brewed coffee is to soak the coffee powder in cold water at room temperature, wait for hours or even days, and then filter the solution repeatedly. The coffee is more profound, bitter and sour, richer and more concentrated than traditional hot brewed coffee. Especially in the hot summer drinking, the cool taste makes people can't stop!

Chemically speaking:

When coffee comes into contact with water, its soluble substances begin to react, resulting in the aroma and taste of coffee as we know it.

The soluble substances in coffee will begin to dissolve under 195205 ℉ of water, so hot brewing coffee should theoretically be richer in taste and taste than cold brewing coffee. Hot water will also accelerate the dissolution rate of soluble substances, making them very volatile, so a large number of substances in coffee will evaporate with water molecules at high temperatures, entering your nasal cavity and making you feel the aroma of coffee.

But accelerating the dissolution of matter also brings some problems. Freshly boiled water can cause some chemical elements in coffee to decay or oxidize, just as iron rust when exposed to large amounts of oxygen, making coffee sour and bitter. If you don't like these two flavors, cold brewing coffee is definitely your best choice.

The oxidation and decay of chemicals also occur in the process of cold brewing coffee, but its rate is very slow, so the bitter and sour taste of cold brewing coffee is softer than that of traditional hot brewing coffee. In addition, slower oxidation and decay make cold brewed coffee easier to preserve, usually for 2-4 weeks in the refrigerator. By contrast, hot brewing coffee has a shelf life of up to one day.

At the moment, you may ask, why is the cold brewing coffee so rich in flavor when the water temperature is so low? Indeed, the water temperature in the process of making cold brewed coffee is much lower than the ideal dissolution and volatilization temperature of aromatic oils and soluble substances, so usually when making cold brewed coffee, you need longer time and double the coffee powder to increase the taste and concentration of the coffee.

Although cold brewed coffee has a richer taste, its aroma is not as good as traditional drip coffee because the aromatic substances in coffee are difficult to volatilize at room temperature. In my opinion, this is the only flaw in cold brewing coffee.

Cold brewed coffee is usually more expensive than hot brewed coffee because of the use of coffee powder and the longer making time. But in fact, you can also make cold brewing coffee at home, and the method is very simple! It's more worthwhile to make it at home than a $4 cup of cold brewed coffee in a coffee shop!