There are mainly several kinds of acids in roasted coffee.

The main acids in roasted coffee are as follows-Zheng Wei (Italian Coffee University)

The following text is based on the first edition of the chemistry of quality.

The main types of acids in roasted coffee are as follows:

Formic acid is the most in shallow baking, and gradually decreases with the deepening of deep baking.

Acetic acid is the most in shallow baking, and gradually decreases with the deepening of deep baking.

Pyruvate has nothing to do with the degree of baking

Lactic acid has nothing to do with baking degree.

Malic acid is the most in shallow baking, and gradually decreases with the deepening of deep baking.

Citric acid is the most in shallow baking, and gradually decreases with the deepening of deep baking.

Quinic acid increases with the decrease of chlorogenic acid.

If you test with ARABICA% or ROBUSTA% and extract 30ml in 30 seconds, they all have a PH of 5.2.

So in terms of PH in the strict sense, coffee is "sour", but acidic and alkaline foods are not the same thing as the acid we usually drink.

The final metabolites of foods with more minerals such as potassium, sodium, calcium and magnesium are often alkaline, such as vegetables, fruits, dairy, soybeans and fungus. Properly paired with alkaline food will help to maintain acid-base balance in the body. The acidity and basicity of food has nothing to do with its own pH value (food that tastes sour is not necessarily acidic food). It is mainly defined by the fact that food is digested, absorbed and metabolized, and finally becomes acidic or alkaline in the human body. Those that produce acidic substances are called acidic foods, such as animal viscera, muscles, plant seeds (cereals). Those that produce alkaline substances are called alkaline foods, such as vegetables, melons, beans, tea and so on.

The following article comes from:

Http://www.alkaline-alkaline.com/acid_alkaline.html

NUTRITION AND ACID-ALKALINE BALANCE

Before World War II, there was considerable interest in how the food we eat affects the acid-alkaline balance of the body. While today the subject is not receiving much attention in orthodox circles, many alternative practitioners place considerable stress on the acid-base balance characteristics of various diets. In spite of a certain amount of ongoing debate, it is generally acknowledged that the food that is eaten is a major source of acid and alkali for the body (7).

Some confusion in terminology has resulted because of the way that the discussion evolved. In investigating how different foods might affect the acid-alkaline balance, various foods were burned to ash in the laboratory, and the pH of the resulting ash was measured. These foods were then classified as acid, alkaline or neutral ash foods as shown in Table 3 (8).

TABLE 3. Acid, Alkaline and Neutral Ash Foods (8)

Acid Ash FoodsAlkaline Ash FoodsNeutral Ash Foods

Bread (grains) cheesearrowroot

Cakecreambutter

Cerealmost fruitcandy

Mayonnaisejamcoffee

Cranberriesmilkcornstarch

Plumsalmondslard

Pruneschestnutsmargarine

Meatcoconutvegetable oil

Brazil nutsmolassespostum

Walnutsmost vegetableswhite sugar

Peanuts syrup

Legumes tapioca

Corn tea

Another way is to ash the food to be tested, and then test the PH value of the ash to determine whether the ingredient is acidic or alkaline.

Summary: for coffee drinkers, we should not think that coffee is alkaline because it contains caffeine (alkaloids), nor because it contains a lot of acid. It is believed that coffee is neutral after being metabolized by the human body, so drinking coffee will not destroy the acid-base balance of our body.