Caffeine is a natural stimulant that can enhance your focus, energy, and mood, and it’s the key ingredient in coffee.
Your coffee’s caffeine content can vary significantly depending on various factors, including the type of coffee bean you use and the type of brew you make. It can range from about 30-175 milligrams (mg) per 5 ounces (147.89 milliliters) of coffee.
The two most common coffee beans are arabica and robusta. Robusta beans generally contain more caffeine than arabica beans. This is due to differences in the beans’ genetic makeup, which determines their ability to produce and store caffeine.
Brewed coffee refers to ground, roasted coffee beans prepared in a drip coffee maker using a filter, water, and a brewing temperature of 197.6 degrees Fahrenheit (92 degrees Celsius).
Brewed coffee contains around 72 milligrams of caffeine per 6-ounce (177.44-milliliter) cup. However, the caffeine content can vary somewhat depending on the variety and roast of the coffee beans.
Espresso is brewed under high pressure using hot water and finely ground coffee beans. The grounds are compacted in the machine’s portafilter basket using a tamper (tool) before brewing.
A powerful shot of espresso (1 ounce, or 29.57 milliliters) may have less caffeine than a 6-ounce cup of brewed coffee—approximately 64 milligrams.
However, espresso has more caffeine per ounce due to the finer grind and its compactness, which allows for more caffeine to be extracted in the brewing process. Even a small 40-milliliter (about 1.33 ounces) shot of espresso can contain as much as 100 mg of caffeine.
Cold brew coffee is a slow extraction process that can take several hours to a day.
It can be prepared at home in a French press by immersing a coarse coffee grind in cold or room temperature water—39-77 degrees Fahrenheit (4-25 degrees Celsius)—for 12-24 hours, then pressing down to separate the liquid extract from the grinds.
Cold-brew coffee is known for its smoother, less bitter taste, but that doesn’t mean it contains less caffeine. Although hot brewing (such as espresso) typically extracts caffeine more quickly due to its high heat processing, the prolonged brewing time in cold brew can also extract a significant amount of caffeine. As a result, cold brews and hot brews can contain similar levels of caffeine.
Some research indicates that a 12-ounce (354.88 milliliters) serving of cold brew may contain 170-245 milligrams of caffeine (an average of 207.22 plus or minus 39.17 milligrams).
A latte has 1-2 shots of espresso (1-2 ounces, or 29.57-59.14 milliliters) and steamed milk. It is usually topped with a layer of milk foam. A 6-ounce latte may provide slightly less caffeine than a 6-ounce cup of brewed coffee. However, typical latte sizes are 12 ounces and 16 ounces (473.18 milligrams), which deliver 130 milligrams and 173 milligrams of caffeine, respectively.
Instant coffee has slightly less caffeine than ground roasts. This is likely due to the process of creating the instant granules.
To make instant coffee, the beans are first roasted and then brewed to make an extract. This extract is freeze-dried to remove the water and turned into granules. During these steps, some beneficial compounds, including caffeoylquinic acids with antioxidant properties, may be lost. Caffeine losses can also occur, but generally to a lesser degree.
There are 46.5 milligrams of caffeine in 6 ounces of prepared instant coffee.
To make decaf coffee, mature coffee beans are steamed to open their pores to release the caffeine. The beans are then treated with a chemical called methylene chloride, which bonds with the caffeine. Finally, the caffeine and methylene chloride are rinsed away.
This process removes 97% or more of the caffeine before roasting the beans. Therefore, a 6-ounce cup of decaf coffee contains less than 3 milligrams of caffeine (2 milligrams per 100 milliliters), compared to 72 milligrams in a regular cup of coffee.
How your coffee is prepared (the temperature, pressure, and brewing time) can affect how much caffeine makes it to your final cup. These factors vary depending on how it is made (brewed coffee, espresso, cold brew, etc.).
The ratio of coffee grounds to water can also affect your coffee’s caffeine content. The more diluted your beverage, the less caffeine it will yield. The caffeine content also depends on how much of the beverage you drink. Other factors that can affect caffeine content include the bean, the roast, and the grind.
The Bean
Robusta beans contain more caffeine than arabica beans due to their genetic makeup, which has a greater capacity to create and store caffeine. The roasting process further enhances the caffeine.
The Roast
Roasting coffee beans is necessary to unlock their color, aroma, and flavor. Without roasting, you’ll get very little flavor or pleasure from drinking your brew, no matter how you prepare it.
Depending on your preference, you can opt for a lighter roast (less bitter, milder flavor) or a darker roast (darker, bolder, and more bitter). A medium roast falls somewhere in between.
Studies suggest that medium roasts may have a higher caffeine content than light and dark roasts due to the level of heat used. Higher temperatures used for dark roasts can decrease the caffeine content.
The Grind
Water will travel through your coffee differently depending on the grind. Smaller particles can clump closer together, creating a larger surface area for extraction and releasing more of the caffeine. A fresh grind also has more caffeine than one that has been sitting in your cupboard.
Here is the caffeine content of some common on-the-go cups of coffee.
Serving Size | Caffeine (mg) | |
McDonald’s coffee | 16 ounces (oz) (large) | 160 |
Starbucks coffee, blonde roast | 16 oz (grande) | 330 |
Starbucks cappuccino | 16 oz (grande) | 150 |
Dunkin’ coffee | 20 oz (large) | 270 |
Beyond the caffeine and flavor, coffee contains a mixture of over 1000 bioactive compounds, which are substances that can deliver health benefits to the body. These compounds have antioxidant potential as well as anti-inflammatory and anti-cancer effects.
Coffee has been associated with a lower incidence of deaths due to heart disease and lower rates of certain types of cancer, metabolic syndrome, and type 2 diabetes.
As a stimulant, caffeine can reduce drowsiness, improve focus and mood, and enhance physical performance. It may also be useful therapeutically, such as in headache or migraine treatment.
It may be safe to consume up to 400 milligrams of caffeine daily, according to the Dietary Guidelines for Americans 2020-2025.
Based on relevant studies, moderate caffeine intake (2-3 cups of coffee, delivering a total of 300 milligrams per day) is not associated with adverse side effects. People who wish to become pregnant (or are pregnant) should limit their intake to 200 milligrams or less daily.
Risks associated with too much caffeine include anxiety, restlessness, insomnia, muscle twitches, rapid heart rate, and stomach aches. Severe side effects can include seizures, hallucinations, palpitations (“racing heart”), dizziness, restricted blood flow, and shortness of breath.
Caffeine, a natural stimulant found in coffee, can vary widely depending on how you enjoy your brew—a classic hot coffee, a creamy latte, or a refreshing cold brew.
Factors that influence caffeine content include the preparation (pressure, temperature, brew time, water-to-coffee ratio), the type of beans, the roast, and the grind size.
Beyond its stimulating effects, coffee offers potential health benefits due to its wide array of bioactive compounds, which can provide antioxidant and anti-inflammatory effects. Stick to recommended upper limits for caffeine to avoid unwanted side effects.