What Is the Strongest Coffee in the World?

What defines the "strongest" coffee? Is it the high caffeine content that energizes us or the intense flavors of deeper, darker, more robust brews?

In general, there are two ways to measure the strength of a coffee:

Caffeine content — very strong coffee contains 30 mg of caffeine per oz (or higher).
Total dissolved solids (TDS) — A measurement of particulate levels suspended in a cup of coffee. Higher TDS indicates a stronger, more concentrated coffee.

The perception of a coffee's strength is influenced by other factors too — such as aroma, roast level, and brewing method. Factors like which ingredients are added (such as milk or sugar) also play a major role in how ‘strong’ the coffee will taste.

In this article, we dive into the facts behind what makes a coffee strong — focusing on everything from bean variety (arabica vs. robusta vs. liberica), roast level, growing conditions, grind level, and brewing method.

In general, the strongest coffees have 5 factors in common:

Prepared with Coffea robusta — particularly Vietnamese culi (peaberry) varieties.
Beans are grown at altitudes of 500 meters above sea level or higher.
The coffee plants are shaded several weeks prior to harvest.
Light to medium-dark roast.
Brewed using an espresso machine, moka pot, ibrik, or phin filter.

>> Try The World's Strongest Coffee: Cafely's BanMe 100% Peaberry Robusta

The Strongest Coffee Beans in the World: Peaberry Robusta

We love strong coffee. Our development team sat down with coffee experts and coffee farmers from around the world to investigate what variables we could control that would deliver the strongest coffee in the world.

The result of this effort is the BanMe coffee beans from Cafely.

These beans are sourced from two small farms in Vietnam — chosen specifically for their adoption of shade-farming techniques. This farming method involves shading the coffee plants from the sun's intense heat during the final few weeks before harvest. This practice maximizes the caffeine content of the final harvest.

Shade farming is labor intensive — but worth it for strong, full-bodied coffee.

To further enhance the caffeine content, we use only the peaberries from these farms for our BanMe coffee. Peaberry coffee (called culi coffee in Vietnam) is a natural mutation of the coffee plant where one concentrated seed forms inside the fruits rather than the usual two.

Why is Vietnamese Coffee So Strong?

Most of the strongest coffees in the world come from Vietnam. This style of coffee is optimized for the flavor and intensity of the local Coffea robusta beans, which is grown on farms all around the country — especially within the volcanic and richly fertile central highlands.

A blend of perfect growing conditions, serious coffee culture, and heavy annual rainfall are the reasons why the Vietnamese produce some of the best coffee in the world.

On top of the richness and intensity of the beans themselves, the method of preparation used to brew Vietnamese coffee (the phin filter) ranks high on the charts for coffees with the most total dissolved solids (TDS) — which is another metric for what makes a coffee strong.

Other strong Vietnamese Coffees:

Cafely’s HaNoi Coffee — made from 100% robusta and contains an average of 300 mg of caffeine per cup. This coffee is nearly twice as strong as a typical cup of arabica coffee.

SaiGon OG — A traditional Vietnamese butter-roast coffee made from a blend of peaberry, robusta, and arabica coffees. A perfect balance of delicate aroma and flavor with the explosive strength of peaberry robusta.

DaNang — A 50/50 blend of highly caffeinated Vietnamese robusta and aromatic arabica.

Related: Try a selection of Vietnam’s strongest coffees with Cafely’s Awakening Bundle.

Strongest Instant Coffees

Instant coffee, by nature, has a high TDS measurement and, depending on how it’s made, can easily deliver more caffeine per cup than fresh brewed coffee.

Instant coffee is considered strong when it has a total caffeine content of 120 mg per cup or more.

The TDS depends entirely on how much instant coffee you use. Typical instant coffee single-serve packs contain between 2 and 3 grams of instant coffee powder.

Check out Cafely’s selection of instant coffees — all of which deliver a strong dose of 150 mg caffeine per pouch (1.5X the amount in a standard coffee):

Instant Vietnamese Milk Coffee (3-in-1)

Instant Vietnamese Coconut Coffee (4-in-1)

Instant Vietnamese Black Coffee (2-in-1)

Caffeine Strength vs. Coffee Strength

Here’s a simple chart to help you determine the strongest coffee brewing method — whether you consider strength to mean caffeine content, total dissolved solids, or both:

Brewing Method	Average Caffeine Content per Ounce	Total Dissolved Solids (TDS)
Espresso	66–80 mg	8–12%
Moka Pot	48 mg	1.4–1.8%
Phin Filter	28–35 mg	1.6–2.2%
Turkish Coffee	25 mg	6–10%
AeroPress	20 mg	1.4–1.7%
Hario V60	12–20 mg	1.2–1.4%
French Press	13–17 mg	1.3–1.8%
Chemex	15 mg	1.25–1.35%
Auto Drip	8–15 mg	1.3–1.6%
Cold Brew	12–13 mg	1.4–1.6

What is TDS? How Does it Affect Coffee Strength?

TDS stands for total dissolved solids — it’s a measurement used to determine the concentration of substances in the brew aside from the water itself.

Coffees with a higher TDS have a stronger, bolder, more intense flavor.

What Makes Some Coffee Stronger Than Others?

The strength of a particular type of coffee depends on several key factors:

Coffee Species & Variety

There are more than 120 different species of the coffee plant (Coffea) — but only 3 are actually used to prepare coffee.

Of these three, Coffea robusta is the strongest. The average bean contains about 2.2% caffeine by weight.

The other two species are comparable in caffeine and roughly half as strong as robusta — Coffea arabica (1.2%) and Coffea liberica (1.3%).

Shop All: Coffea Robusta Beans

Climate Conditions

The manufacture of caffeine in the coffee plant requires many steps and steady access to essential nutrients. Without a plentiful supply of elements like nitrogen, hydrogen, phosphorous, oxygen, and carbon, as well as trace minerals like magnesium, zinc, and iron — caffeine production can become stunted.

Coffee plants grown in highly nutritive soils consistently demonstrate the highest total caffeine levels. This often (but not always) means volcanic soil, which is particularly rich in potassium and phosphorus — both of which are critically involved in the production of caffeine.

Other important climate conditions include high annual rainfall (2000 mm or higher) and temperatures that never dip below freezing.

Altitude also plays a role. Robusta has been shown to thrive at altitudes of 500 to 800 meters above sea level. Generally speaking, the lower the altitude, the more caffeinated the beans.

Coffee plants may grow and produce fruits under conditions that are not ideal, but every compromise leads to a reduction in the potency of the final brew.

How the coffee plant makes caffeine: 5-phosphoribose-1-pyrophosphate (PRPP) → 5′-monophosphate → xanthosine → 7-methylxanthosine → 7-methylxanthine → theobromine → caffeine [1].

Roast Level

After the coffee beans are separated from the fruit and dried, they need to be roasted in order to bring out the characteristic bold flavors of coffee.

Roasters have 3 main levels they can roast their coffee to (plus mid-stages in between).

The level of roast will have an impact on both the total caffeine content of the coffee as well as flavor intensity:

Light Roast Coffee — These coffees are more acidic and fruity and maintain the highest caffeine content. This is because the heat involved with roasting can degrade some of the caffeine.
Medium Roast Coffee — These coffees balance the full-body taste while preserving much of the caffeine content.
Dark Roast Coffee — These coffees are often considered the strongest tasting, converting more of the sugars, fats, and amino acids to new aromatic compounds. The tradeoff is that the longer exposure to higher temperature degrades more of the caffeine in the final bean.

Grind Size

The grind size of a coffee impacts the strength of the final brew in two key ways:

First, finer grinds contain more small particulate that can make its way into the final brew if it isn’t effectively filtered out. For brewing methods like the French press, moka pot, espresso machine, and Turkish ibrik — finer grinds will produce a stronger coffee with higher TDS levels.

Brewing methods that involve fine particulate filters — such as the AeroPress, auto drip, or pour-over systems will remove these particles — rendering the grind level far less critical.

The second way grind size impacts the strength of a coffee comes down to the extraction of caffeine. Smaller particles allow more contact between the solvent (water) and the beans — which results in a more efficient extraction. This means that coffees brewed using finely ground coffee contain more caffeine than coarse-ground coffees when steeped under the same conditions.

Brewing Method

The brewing method has a major impact on the strength of a coffee.

Methods that optimize for caffeine content typically allow for longer steeps, use a more finely ground coffee, or involve higher water temperatures.

Brewing methods like the Turkish ibrik, Vietnamese phin filter, and espresso produce the strongest coffee overall (measured by a combination of TDS and caffeine content). Cold brew and pour-over have lower TDS but extract relatively high levels of caffeine.

Let’s explore in greater detail how each brewing method affects the strength of coffee…

Brewing Methods That Produce the Strongest Coffee

Brewing very strong coffee depends as much on the brewing method as it does the species of coffee, grind size, and growing conditions. Here are the strongest brewing methods ranked in order.

Note: Strength is measured by a combination of caffeine level and total dissolved solids (TDS).

1. Ibrik (Turkish Coffee)

Turkish coffee is made from very finely ground arabica coffee, which is brewed directly in a specialized pot called an ibrik. This brew style produces the strongest coffee of them all because the grounds are left unfiltered in the final brew. None of the particular is removed, and the coffee beans are consumed entirely — delivering 100% of the caffeine contained inside.

Some might argue that the caffeine degrades under the intense heat used to brew Turkish coffee, but studies have found this to be insignificant [2]. The average Turkish coffee made from arabica coffee delivers about 95 mg of caffeine per 100 mL.

2. Phin Filter (Vietnamese Coffee)

The traditional Vietnamese phin filter (our favorite brewing device) produces notoriously strong coffee. Typically used with the stronger robusta coffee beans and subjected to long extraction times and a metal filter designed to allow some particulate into the final brew has a notoriously high TDS and caffeine level.

Vietnamese coffee is typically brewed to be as concentrated as possible (similar to espresso) and combined with intensely sweet condensed milk for an explosion of flavor.

3. Cold Brew Coffee

Cold brew coffee is brewed using cold water over the course of 24 or 36 hours. This long brew time allows for the maximum extraction of caffeine from the beans as possible. This brew method contains very high caffeine levels.

The total dissolved solids in this style of coffee depend on how the coffee is filtered. For a stronger, more full-bodied taste, a coarser filter (such as cheesecloth or a 200-micron sieve) can be used. For a cleaner, brighter coffee with less sediment, fine particular filters, such as the thick Chemex-style filter, can be used.

4. Hario V60 (Pour Over)

The Hario V60 is a specialty pour-over device designed in Japan for the most consistent extraction possible. This style of coffee has notoriously high caffeine levels thanks to several innovations in filter and design technology.

The filters used for the Hario V60 are thinner than those used for other styles of pour-over (such as the Chemex), which allows more particulate to enter the cup (bringing their robust flavors along with them).

5. Moka Pot (Stovetop Espresso)

The Italian moka pot forces boiling, pressurized water through finely-ground coffee. They feature a built-in filter that blocks the largest particles from entering your cup.

The caffeine and TDS levels of moka coffee are comparable to espresso machines. These coffees are great for concentrating strong coffee into a small volume — a common characteristic of all the strongest brewing methods.

6. French Press

The French press is one of the most versatile brewing methods available. By controlling the water temperature, coffee-to-water ratio, and brewing time, users can dial in the strength of their coffee to exactly how they like it.

For a very strong coffee, consider using robusta coffee, a coffee-to-water ratio of 1:8, near-boiling water, medium grind, and an extraction time between 5 and 6 minutes.

7. Espresso

The classic espresso machine uses specialized equipment to force pressurized water through very finely ground coffee — producing a highly concentrated shot of coffee in seconds. A typical shot of espresso contains around 75 mg of caffeine.

How Much Caffeine is Too Much?

The FDA suggests the safe upper limit of caffeine is around 400 mg per day. This is based on several years worth of research, along with a healthy margin of precaution.

Several studies have shown that humans can tolerate much higher levels of caffeine without risk — however, individual sensitivities, tolerance, and body weight can all affect this.

The 400 mg line drawn in the sand describes the safe dose for the average person who is a non-coffee drinker. Tolerance to caffeine is a known phenomenon whereby frequent coffee drinkers become less sensitive to the effects of caffeine over time. As this occurs, the body can tolerate higher levels of caffeine before experiencing side effects.

An adjusted guideline of 5.7mg/kg was proposed by the European Food Safety Authority — which is based on body weight for a more accurate calculation. For the average 70 kg female (150 lbs), this works out to 400 mg caffeine. For the average 78 kg male (170 lbs), this is closer to 450 mg per day.

More advanced studies are currently underway to determine how variables like tolerance and genetic sensitivities to caffeine (usually involving the CYP1A2 gene) affect the safe upper limit (and effective dose) of caffeine in different people.

Summary: How to Brew the Strongest Coffee Possible

So, after all of that, what, exactly, should I do to brew the strongest coffee possible?

Start with peaberry robusta coffee beans — check out our BanMe coffee beans.
Grind your beans to the consistency of sugar (fine grind).
Brew your coffee using a phin filter or moka pot.
Avoid adding any additional water and only minimal liquid sweeteners.

Alternatively, all three of our Vietnamese Instant Coffees (milk, coconut, and black coffee) contain a whopping 150 mg of caffeine per pouch. Double them up for an extra powerful kick.

Related: Vietnamese Coffee Grind Size

FAQs: Strong Coffee

1. What defines the strongest coffee?

A coffee’s strength is defined by a combination of its caffeine content, total dissolved solids (TDS), and aroma. Factors like brewing method, grind size, bean variety, and growing conditions all impact the strength of the final brew.

2. Why is robusta coffee considered stronger than arabica?

Robusta coffee contains higher caffeine levels, approximately 2.2% by dry weight, compared to arabica's 1.2%.

3. How does roast level affect the strength of coffee?

Light roasts retain the most caffeine as less is degraded by heat, while medium and dark roasts enhance flavor intensity but may decrease caffeine content due to longer roasting times.

4. Which brewing methods produce the strongest coffee?

The strongest coffee is typically brewed using methods like the ibrik (Turkish coffee), the phin filter (Vietnamese coffee), espresso, and moka pot — each of which optimizes caffeine content and flavor concentration.

5. Can growing conditions affect the strength of coffee?

Yes, factors such as altitude, climate, and soil quality significantly influence the caffeine levels and flavor profile of coffee. In general, coffee grown at higher altitudes, in nutrient-rich soil, and receiving plenty of annual rainfall will produce the highest caffeine levels and develop a more intense flavor profile.

6. What are the health guidelines for caffeine consumption?

The FDA recommends a safe limit of 400 mg of caffeine per day for the average adult, though this can vary based on individual tolerance and body weight. A more accurate measurement uses body weight instead. The EFSA suggests a safe limit of around 5.7 mg of caffeine per kilogram of body weight.

7. What special techniques are used to enhance the strength of coffee like Cafely’s BanMe beans?

Techniques such as shade-farming and using only peaberries from selected Vietnamese farms help maximize the caffeine content and enhance the flavor profile of Cafely’s BanMe coffee beans.

8. How does instant coffee compare in strength to fresh brewed coffee?

Instant coffee can be very strong, typically containing 120 mg of caffeine or more per cup. It has a high TDS measurement, making it a convenient option for those seeking a strong coffee quickly.

Cafely’s instant coffee blends provide even more caffeine per packet, at 150 mg each.

References

Lin, Z., Wei, J., Hu, Y., Pi, D., Jiang, M., & Lang, T. (2023). Caffeine synthesis and its mechanism and application by microbial degradation, a review. Foods, 12(14), 2721.
Fuller, M., & Rao, N. Z. (2017). The effect of time, roasting temperature, and grind size on caffeine and chlorogenic acid concentrations in cold brew coffee. Scientific reports, 7(1), 17979.
Fox, G. P., Wu, A., Yiran, L., & Force, L. (2013). Variation in caffeine concentration in single coffee beans. Journal of agricultural and food chemistry, 61(45), 10772-10778.