Coffee enthusiasts often debate which roast, dark or light, contains more caffeine. This question has lingered, fueled by myths and assumptions. Recently, we explored this topic in detail, diving into scientific research to reveal the truth behind the caffeine content in different coffee roasts.
TL:DR: Third wave light and dark roast coffees have the same caffeine levels. Dark roasts with the First and Second wave methodologies roasted beyond 235°C will have less caffeine.
Understanding Caffeine Basics
Caffeine, a natural stimulant, is often celebrated for its ability to increase alertness and energy. Understanding its properties is crucial for discussing its presence in coffee.
Thermostability of Caffeine
Caffeine is known to be thermostable, meaning it maintains its structure up to a specific temperature—precisely 235 degrees Celsius. Beyond this point, caffeine begins to break down and evaporate, impacting its presence in the roasted bean.
Roasting Process and Temperature Spectrum
The roasting process transforms green coffee beans into the aromatic beans we use to brew coffee. This involves a temperature spectrum crucial to determining the characteristics of the final product.
From Green Beans to Roasted Beans
Coffee roasting starts at room temperature with green beans. As temperatures rise, the beans undergo significant changes until reaching approximately 245 degrees Celsius. This range is where most roasting activities, from light to dark, occur.
The Myth and Misconceptions About Caffeine Levels
Misunderstandings about caffeine levels in coffee roasts are rampant. Many believe that darker roasts always have less caffeine than lighter roasts and some believe that it is the opposite with light roasts having more caffeine than dark roasts.
The prevalent belief is that darker roasts are higher in caffeine, due to their stronger flavor. In reality, the intense flavors in darker roasts are not indicative of higher caffeine levels.
Roasting Waves
The evolution of coffee roasting can be categorized into waves, each with distinct roasting methods and flavor focus.
First and Second Coffee Waves
During the first and second waves of coffee, dark roasting was predominant, often going beyond 235 degrees Celsius. This methodology results in a noticeable reduction in caffeine levels due to the breakdown of caffeine compounds.
Third Wave Coffee
In contrast, the third wave emphasizes the natural flavors of coffee beans. Roasters in this category typically avoid exceeding the 235-degree threshold to preserve the bean’s original taste profile and caffeine content.
Roasting Dynamics
The physical changes beans undergo during roasting, such as cracks, are pivotal in understanding roasting levels.
Understanding the Crack in Roasting
During roasting, beans experience expansion and cracking. The first crack typically marks the transition into a light roast. The second crack indicates a move toward a dark roast. These cracks cause beans to expand, affecting their density and size.
The expansion of beans during roasting causes a decrease in density, influencing the caffeine content by volume and weight.
Findings from Kicking Horse
Research from Kicking Horse reveals that dark roasts lose the weight of approximately 90 beans per pound. Despite the caffeine’s thermostability, this loss is critical when assessing moisture content and measuring caffeine by volume and weight.
Measurement Methods Impacting Caffeine Levels
The perceived caffeine level can vary depending on how coffee is measured, by weight or volume.
Measuring by Weight: Dark Roasts
When measured by weight, dark roasts tend to have more caffeine because they are less dense. This leads to more coffee beans per gram, increasing the caffeine content.
Measuring by Volume: Light Roasts
Conversely, when measured by volume, such as using a scoop, light roasts can appear to have more caffeine. The smaller bean size results in more beans per scoop.
OCD Measurement: Counting Beans
When measured by the exact number of beans, both light and dark roasts offer similar caffeine amounts, as the variance in density counterbalances the difference in size.
Caffeine and Bitterness in Coffee
The bitterness in coffee is often mistakenly attributed solely to caffeine content, when in fact, other factors significantly contribute.
Contribution of Caffeine to Bitterness
Caffeine accounts for approximately 15% of coffee’s bitterness. The remaining 85% emerges from the roasting level and bean extraction.
Different Bean Varietals
The type of coffee bean used also affects caffeine levels.
Comparison Between Arabica and Robusta Beans
Arabica beans, typically used in lighter roasts, naturally have less caffeine. Meanwhile, robusta beans, often roasted darker, boast around 30% more caffeine.
Research and Study Analysis
Scientific studies offer insights but can vary in methodology and findings. It’s important to critically examine research procedures.
Scrutinizing Research Methodologies
Research often explores the extremes, but methodological flaws can skew results. One study noted a massive reduction in caffeine for darker roasts—however, its roasting method was unrealistic for quality coffee production.
By locking the time at 25min and roasting at three different temperatures, you don’t produce beans that can be brewed well for coffee. Dark roasts will be charred to bits, while the light roast was probably under-developed.
Reliable Study on Roast Levels and Caffeine
A comprehensive study examined different roast levels in both arabica and robusta beans under reasonable conditions. It confirmed caffeine’s thermostability, showing no significant difference in caffeine content across roast levels.
Visual Representation of Data
Understanding data through visual aids helps in comprehending changes in caffeine content and roasting levels.
The top left graph (A) depicts caffeine in grams per 100 grams of coffee reveal correlations with roast levels. A higher index of reflectance denotes a lighter roast, while a lower index indicates a darker roast.
Conclusion
So to summarize it all, research concludes that third wave light and dark roast coffees maintain similar caffeine levels. In contrast, dark roasts aligned with first and second wave practices, exceeding 235 degrees Celsius, show reduced caffeine.
The discussion of caffeine in coffee roasts can be complex, yet understanding the science can dispel myths and clarify common misconceptions. Hopefully this post shed some light on its complexities and made things a bit more clear!