Does Light Roast Coffee have Less Caffeine?

Light Roast Coffee

There are countless ways to make your coffee, french press, percolator, instant, and so on. Just as there are ways to brew it, there are thousands, perhaps even more ways to have it, drink it black, have it iced, mocha, latte, or come up with a unique artisan hybrid drink. But many folks just want a simple light or dark roast, some will pick a light roast if they want something that isn’t very strong, but does light roast coffee really have less caffeine?

Light roasts can have a very, small amount of more caffeine. As it turns out, the caffeine content in a dark roast and light roast is nearly the same. However, what actually influences caffeine is the weight and volume, the size of the grind, the brewing method, the variety of coffee, and its concentration.

Keep reading to find out how these factors play into the caffeine of coffee.

What makes a strong coffee?

Several things influence the strength of coffee:

  • Roasting
  • Weight
  • Volume
  • Brewing Method
  • Grind
  • Variety
  • Concentration

Does Roasting make a difference?

Before beginning the roasting process, when the beans are still raw, they can have different levels of caffeine. To make any big changes, the temperature would need to reach about 600°F (about 315.6°C) to make an impact on the coffee beans’ caffeine content. But since roasting heat barely goes near 500°F (260°C) they are both still similar in the amount of caffeine, what makes the difference is how the heat changes the beans’ density.

As the beans are roasted their volume and weight changes, since dark roast coffee is roasted longer, it loses more weight, volume, and some caffeine. Light roast retains more of its weight, making it more concentrated in caffeine, but only by a very small margin. What would determine the amount of caffeine in a serving would be how the coffee is measured before it’s made into a cup of joe.

Measuring Weight and Volume is Key 

Weight of course refers to how heavy the coffee beans are, volume refers to how much space they take up, or how big they are. When you roast them they lose water weight. Light roasts retain more weight because they are roasted for a shorter time but they also keep the small size, so they have less volume. Dark roasts lose more water and have less weight but the beans become bigger, giving them more volume. 

How you measure them is very important, if you measure light roasts by volume, a cup of light will have more caffeine than dark, why? Since light roasts are denser take up less space by having less volume, you can fit more beans in a cup, thus having more caffeine. If you did this with a dark roast, you would have fewer beans in the measuring cup because they have taken up more volume but are less dense, making a cup that wouldn’t be as strong. 

By flipping it around and measuring by weight, which is a common practice by most coffeehouses, 2 lbs of the dark would have more caffeine than 1 lb of light. Simply because more dark coffee beans and you aren’t worrying about how much space it takes, rather how much mass it has.

Does Brewing Method and Grind Matter?

The method you choose to brew your coffee also plays a part. Hotter water draws more caffeine from the beans and methods that immerse the beans in hot water lets them brew for longer.

Another factor that affects the amount of caffeine is the size of the grind. The ratio of the surface area of the grind to the volume is greater which makes beans with a smaller grind bump up the amount of caffeine in a cup. The smaller the grind, the stronger the coffee. 

Different Varieties Have Different Caffeine Content

While there’s not too much difference in roasts, there is a difference in caffeine concentration when it comes to the variety of coffee. The two most commonly known types of beans are Arabica and Robusta. Arabica is the most commonly used because of its smooth, sweeter, and more pleasant taste. Robusta is known for its strength and powerful flavor. 

Robusta is often added to Arabica mixes to boost its strength, this is because Robusta has nearly double the caffeine when compared to its more common counterpart. Arabica comes in at about 1.5% caffeine at its dry weight whereas Robusta is around 2.7% caffeine, which is about 10% of its total weight. This is a reason why Robusta beans are put into espressos. And since its fairly common in places like southeast Asia, most people who visit are surprised to by the kick when they go to a cafe in that part of the world.

The Higher the Concentration, the Higher Caffeine

Possibly the most important part of the strength of a cup of coffee, the concentration of coffee means how much there is in comparison to the water content. For example, there’s less coffee compared to liquid in a cold brew in a ratio, its about 1 part coffee to 3 to sometimes 8 parts liquid. A shot of espresso on the other hand, while smaller has around 1 part coffee to 2 parts liquid.

Coffee is What You Make of It

Now you know that light and dark roasts don’t have that much of a difference when it comes to the caffeine content. Rather, it’s the coffee you choose and the way you prepared it that matters. Things like measuring, brewing, variety, and concentration are vital in determining that caffeine kick we need for the day.