Science of Cacao: Cacao & Coffee — Research and the Art of the Blend
Coffee brings its roasted aroma and familiar wake-up character. Cacao brings chocolate depth, a fuller texture, and a different balance of naturally occurring compounds. There is plenty to appreciate in each cup—and plenty to explore when the two meet.
This guide explores the research on combining cacao and coffee, then brings the pairing into the kitchen. For the individual compounds and serving-size comparisons, follow the companion articles below.
Cacao and coffee together: what does the research show?
There is a good reason to be curious about the combination. Researchers have tested cocoa, caffeine, theobromine and cocoa flavanols in different formulations. The results offer promising observations, alongside a reminder to pay attention to exactly what was tested.
An encouraging attention study
A 2017 randomized, double-blind crossover study compared four beverages: brewed cocoa, cocoa with added caffeine, caffeine alone and placebo. Twenty-four people participated, with 23 included in the final analysis. Each person tried the different drinks on separate days. [3]
Attention: cocoa with added caffeine improved accuracy and reduced missed responses on one attention task compared with cocoa alone. [3]
Anxiety during testing: the combined drink reduced the increase in anxiety seen after caffeine alone during demanding cognitive testing. [3]
The study was supported by The Hershey Company and tested a particular brewed-cocoa formulation. It did not test a homemade mocha, Green Flare, or theobromine alone. Its findings are a reason for further interest, not proof that adding cacao will prevent caffeine-related anxiety for everyone. [3]
The wider picture is mixed
Earlier work by Smit and colleagues found similar improvements in energetic arousal and cognitive function after cocoa powder and a caffeine–theobromine combination. This supports a role for cacao’s methylxanthines in some short-term effects. It does not establish that every coffee-and-cacao mixture will outperform coffee. [4]
A separate 2011 study tested caffeine, theobromine, their combination and placebo in 24 women. The combination’s mood effects resembled caffeine alone, and none of the treatments improved performance on the study’s psychomotor task. [5]
More recently, a 48-person crossover trial tested 415 mg of cocoa flavanols, 215 mg of caffeine, both together and placebo. It found no measurable improvement in the tested attention and working-memory outcomes. The paper appeared online in 2024 and in a 2025 journal volume. [6]
What “synergy” would actually mean
In everyday conversation, synergy can simply mean that two ingredients work well together. In research, demonstrating an interaction requires more than showing that a combined drink performed well on one task. Researchers need comparisons that separate the contributions of the ingredients.
Whole cocoa also brings more than theobromine. A finding for cocoa plus caffeine cannot automatically be credited to theobromine, and a flavanol study does not test the same formulation as a whole-cacao drink.
The pairing is compelling. The evidence is specific: some favorable findings, different results across studies, and no universal promise of better focus.
Choose the cup you actually want
For a rich cacao morning
Choose plain cacao when you want chocolate flavor to lead. Water lets its character come through clearly; milk or a plant-based alternative gives a creamier result. Start with the product’s preparation guidance, then adjust the liquid and sweetness to your taste.
At XOL, Pure Love is the straightforward starting point for that experience. It also gives you a base for experimenting with cinnamon, vanilla, or a little coffee on another day.
For cacao with coffee character
If you enjoy both ingredients, try a small amount of coffee in a cacao drink and build toward the balance you like. Too much coffee can hide the cacao; too much sweetness can flatten the detail in both.
Green Flare brings cacao together with freeze-dried espresso powder, green coffee bean extract and a seawater mineral complex. Its coffee ingredients contribute additional naturally occurring caffeine. It is a different choice from plain cacao, even though both start with cacao.
Green Flare has not been clinically tested, and its product page does not state caffeine or theobromine milligrams per serving. The studies above explain the research interest in these ingredients; they are not clinical claims about the blend.
A simple cacao-and-coffee cup
A starting recipe to adjust to taste: about 15 g of plain cacao, 30–60 ml of brewed coffee, and 180–240 ml of hot water or your preferred milk. Optional: cinnamon or a little sweetener.
Melt and disperse the cacao in a small amount of the hot liquid, whisking or frothing until smooth.
Add the remaining water or milk, then stir in the coffee gradually. Taste before adding more.
Adjust the sweetness and finish with a little cinnamon if you like. Leave room in the cup while frothing.
For a lighter coffee contribution, use decaf; it still contains some caffeine. If you use Green Flare instead of plain cacao, follow its one-coin preparation guidance first—it already contains coffee ingredients. [9]
Find your own balance
You can love cacao without giving up coffee. You can also make cacao the center of your morning because you prefer its flavor and texture. The most useful choice is the one that fits your taste, your serving, and the way you want to enjoy the day.
New to preparing cacao? Follow our one-coin cacao guide.
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